technetium-tc-99m-exametazime and Epilepsy--Temporal-Lobe

Radiopharmaceutical brain imaging is clinically applied in planning resective epilepsy surgery. Cerebral sites of seizure generation-propagation are highly associated with regions of hyperperfusion during seizures, and with glucose hypometabolism interictally. For surgical planning in epilepsy, the functional imaging modalities currently established are ictal single photon emission computed tomography (SPECT) with [(99m)Tc]technetium-hexamethylpropyleneamine oxime (HMPAO) or with [(99m)Tc]technetium-ethylene cysteine dimer (ECD), and interictal positron emission tomography (PET) with 2-[(18)F]fluoro-2-deoxyglucose (FDG). Ictal SPECT and interictal FDG PET can be used in presurgical epilepsy evaluations to reliably: (1) determine the side of anterior temporal lobectomy, and in children the area of multilobar resection, without intracranial electroencephalographic recording of seizures; (2) select high-probability sites of intracranial electrode placement for recording ictal onsets; and, (3) determine the prognosis for complete seizure control following anterior temporal lobe resection. Coregistration of a patient's structural (magnetic resonance) and functional images, and statistical comparison of a patient's data with a normal data set, can increase the sensitivity and specificity of these SPECT and PET applications to the presurgical evaluation.

Topics: Brain; Cysteine; Epilepsy; Epilepsy, Absence; Epilepsy, Generalized; Epilepsy, Temporal Lobe; Fluorodeoxyglucose F18; Humans; Organotechnetium Compounds; Predictive Value of Tests; Preoperative Care; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed; Tomography, Emission-Computed, Single-Photon

Intracranial aneurysms in the pediatric age group are rare occurrences. They usually present with subarachnoid hemorrhage or mass effect. Their association with epilepsy has rarely been reported; such concurrence may not be a coincidence. We present a 16-year-old girl with a 5-year history of medically intractable complex partial seizures. Preoperative electrophysiological and neuroimaging studies demonstrated an epileptogenic focus and atrophy in the right mesial temporal lobe, and ipsilateral incidental aneurysm at the carotid artery bifurcation. The patient underwent a complete right anterior temporal lobectomy, followed by clipping of the aneurysm. We concluded that the epilepsy management in association with cerebral aneurysms is controversial, but when surgery is indicated, clipping of the aneurysm and resection of the epileptogenic focus may provide the optimal outcome. The relevant literature is reviewed and the possible mechanisms of production of epilepsy by intracranial aneurysms are discussed.

Topics: Adolescent; Atrophy; Cerebral Angiography; Electroencephalography; Epilepsy, Complex Partial; Epilepsy, Temporal Lobe; Female; Humans; Intracranial Aneurysm; Magnetic Resonance Imaging; Psychosurgery; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon

Brain imaging has become an integral part of the evaluation of neurological and psychiatric disorders. Functional imaging techniques, SPECT and PET, together with structural modalities, CT and MRI, are widely employed. Functional imaging studies are routinely used in the diagnostic workup of patients with well-characterized neurological disorders, such as epilepsy and brain tumors, and have a growing role in research on psychiatric disorders without known mechanisms such as depression and schizophrenia. Furthermore, many well-defined neurological disorders manifest prominent psychiatric symptomatology which may pose difficulties in differential diagnosis. This review addresses the current knowledge of SPECT findings in patients who present with psychiatric phenomena, associated with disorders at the interface of neurology and psychiatry.

Topics: Alzheimer Disease; Brain; Brain Damage, Chronic; Brain Diseases; Brain Injuries; Brain Neoplasms; Dementia; Diagnosis, Differential; Epilepsy, Temporal Lobe; Humans; Huntington Disease; Neurocognitive Disorders; Organotechnetium Compounds; Oximes; Parkinson Disease; Regional Blood Flow; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

The yield of ictal, postictal, and interictal SPECT was compared in the localisation of seizure foci in 177 patients with partial epilepsy. In 119 patients with known unilateral temporal lobe epilepsy ictal SPECT (97% correct localisation) was superior to postictal SPECT (71% correct), which was better than interictal studies (48% correct). Similarly, in cases of known or suspected extratemporal epilepsy the yield of ictal SPECT studies was high (92%). By contrast, the yield of postictal studies was much lower (46%) and usually only very early postictal studies were diagnostic. Interictal SPECT was of little value. The accuracy of ictal SPECT in localising temporal lobe seizures is now well established. Extratemporal seizures are often brief and difficult to localise. This report shows that ictal SPECT also has a high diagnostic yield in a wide range of extratemporal epilepsies. The brevity of many extratemporal seizures means that true ictal SPECT examinations can be difficult to achieve, but the high diagnostic yield justifies the special organisational effort needed to obtain such studies.

Topics: Epilepsies, Partial; Epilepsy, Temporal Lobe; Humans; Organotechnetium Compounds; Oximes; Reproducibility of Results; Sensitivity and Specificity; Single-Blind Method; Technetium Tc 99m Exametazime; Time Factors; Tomography, Emission-Computed, Single-Photon

Single photon emission tomography (SPECT) was performed in 27 patients with refractory complex partial seizures from the temporal lobes due to mesial temporal sclerosis. Independent blinded observers assessed the 28 interictal studies and 9 ictal/postictal studies. Visual analysis of interictal studies detected hypoperfusion in 22, ipsilateral to the epileptogenic zone in 19 (67%) and contralateral in 3 (10.7%). Quantified temporal lobe asymmetry, greater than a previously derived normal range, correctly identified the epileptogenic zone in 16 (61.5%) with false lateralization in 4 (15.3%). In all 9 cases in which they were performed, ictal/postictal studies showed hyperperfusion at the region of epileptic focus. In 3 patients with complex partial seizures followed by symmetric generalized tonic-clonic seizures, hyperperfusion restricted to the temporal lobe was demonstrated. In 5 of these patients the interical studies were unable to demonstrate localized changes. There were no significant correlations between SPECT findings and clinical parameters or EEG slowing in the temporal lobes.

Topics: Adolescent; Adult; Electroencephalography; Epilepsy, Temporal Lobe; Female; Follow-Up Studies; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Organotechnetium Compounds; Oximes; Oxyquinoline; Postoperative Period; Predictive Value of Tests; Sensitivity and Specificity; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

The respective contribution of interictal HMPAO-SPECT and FDG-PET to the imaging of the epileptogenic zone in intractable temporal lobe epilepsy is not known. Ten consecutive patients with drug resistant focal epilepsy of temporal lobe origin were studied with prolonged noninvasive video-EEG monitoring, magnetic resonance imaging, interictal FDG-PET and HMPAO-SPECT. Five patients demonstrated unitemporal and 5 patients bitemporal interictal and/or ictal EEG epileptiform abnormalities. We developed a 3-dimensional semiquantitative method for interpretation and comparison of FDG-PET and HMPAO-SPECT using a 15-compartment model of the temporal lobe. In all 5 patients with unilateral epileptogenicity, interictal hypometabolism and hypoperfusion were recorded on the side of the EEG abnormalities without discrepancy between PET and SPECT. The severity and the extent of focal abnormalities were consistently greater on PET than on SPECT, in agreement with previously well documented better 'sensitivity' of PET. Among the 5 patients with bitemporal epileptogenicity, results of SPECT and PET were convergent in only 2 cases. In this group, SPECT abnormalities appeared more profound but either SPECT or PET were not constantly correlated with the side of predominant EEG epileptogenicity. Abnormalities on PET and SPECT were more frequently limited to mesiobasal structures among cases with unilateral epileptogenicity and tended to involve neocortical structures in bitemporal cases. We conclude that interictal FDG-PET and HMPAO-SPECT provide the same type of information on the side of the epileptogenic zone in cases with clearly unilateral epileptogenicity, with abnormalities more intense and more extensive on PET.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adult; Deoxyglucose; Electroencephalography; Epilepsy, Complex Partial; Epilepsy, Temporal Lobe; Female; Fluorodeoxyglucose F18; Humans; Male; Middle Aged; Models, Biological; Organotechnetium Compounds; Oximes; Reproducibility of Results; Single-Blind Method; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed; Tomography, Emission-Computed, Single-Photon; Videotape Recording

Topics: Epilepsy, Temporal Lobe; Humans; Organometallic Compounds; Oximes; Technetium Tc 99m Exametazime; Temporal Lobe; Time Factors; Tomography, Emission-Computed

Medial temporal lobe epilepsy (MTLE) is associated with limbic atrophy involving the hippocampus, peri-hippocampal and extra-temporal structures. While MTLE is related to static structural limbic compromise, it is unknown whether the limbic system undergoes dynamic regional perfusion network alterations during seizures. In this study, we aimed to investigate state specific (i.e. ictal versus interictal) perfusional limbic networks in patients with MTLE.. We studied clinical information and single photon emission computed tomography (SPECT) images obtained with intravenous infusion of the radioactive tracer Technetium- Tc 99 m Hexamethylpropyleneamine Oxime (Tc-99 m HMPAO) during ictal and interictal state confirmed by video-electroencephalography (VEEG) in 20 patients with unilateral MTLE (12 left and 8 right MTLE). Pair-wise voxel-based analyses were used to define global changes in tracer between states. Regional tracer uptake was calculated and state specific adjacency matrices were constructed based on regional correlation of uptake across subjects. Graph theoretical measures were applied to investigate global and regional state specific network reconfigurations.. A significant increase in tracer uptake was observed during the ictal state in the medial temporal region, cerebellum, thalamus, insula and putamen. From network analyses, we observed a relative decreased correlation between the epileptogenic temporal region and remaining cortex during the interictal state, followed by a surge of cross-correlated perfusion in epileptogenic temporal-limbic structures during a seizure, corresponding to local network integration.. These results suggest that MTLE is associated with a state specific perfusion and possibly functional organization consisting of a surge of limbic cross-correlated tracer uptake during a seizure, with a relative disconnection of the epileptogenic temporal lobe in the interictal period. This pattern of state specific shift in metabolic networks in MTLE may improve the understanding of epileptogenesis and neuropsychological impairments associated with MTLE.

Topics: Adult; Child; Child, Preschool; Demography; Epilepsy, Temporal Lobe; Humans; Infant; Middle Aged; Nerve Net; Perfusion; Radionuclide Imaging; Seizures; Technetium Tc 99m Exametazime; Young Adult

Locating and excising epileptogenic zones is the traditional treatment in pharmacoresistant temporal lobe epilepsy. Some patients, however, continue to suffer from attacks even after surgery. Therefore, new hypotheses must be formulated in order to account for the apparent shortcomings of correctly performed surgical procedures.. An approach that is not traditional in the field, namely complex networks, is used to attempt to show that modifying the properties of the limbic network can lead to the elimination of the attacks, regardless of the location of the epileptogenic zones.. The intraoperative electrocorticographic recordings of 20 patients with pharmacoresistant temporal lobe epilepsy were utilised in the study. An analysis of complex networks was used to study the local synchronisation activity in the lateral and mesial cortex of the temporal lobe and, essentially, the zones with the highest temporal stability were determined.. Those cortical zones with higher synchronic activity are associated with a greater temporal stability and when these zones are excised during surgery, the patient no longer suffers any disabling attacks. In contrast, when these zones are not excised, the patient continues to have attacks in the post-operative period.. The findings support the hypothesis of the existence of a limbic network, which the lateral and mesial cortices of the temporal lobe are part of, and whose capacity to establish an overall synchronisation is affected when certain zones are removed.

Topics: Adult; Algorithms; Cortical Synchronization; Electroencephalography; Epilepsy, Temporal Lobe; Female; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Models, Neurological; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon; Young Adult

This study assesses the utility of compartmental analysis of SPECT data in lateralizing ictal onset in cases of a putative mesial temporal lobe epilepsy (mTLE). An institutional archival review provided 46 patients (18M, 28F) operated for a putative mTLE who achieved an Engel class Ia postoperative outcome. This established the standard to assure a true ictal origin. Ictal and interictal SPECT images were separately coregistered to T1-weighted (T1W) magnetic resonance (MR) image using a rigid transformation and the intensities matched with an l(1) norm minimization technique. The T1W MR image was segmented into separate structures using an atlas-based automatic segmentation technique with the hippocampi manually segmented to improve accuracy. Mean ictal-interictal intensity difference values were calculated for select subcortical structures and the accuracy of lateralization evaluated using a linear classifier. Hippocampal SPECT analysis yielded the highest lateralization accuracy (91%) followed by the amygdala (87%), putamen (67%) and thalamus (61%). Comparative FLAIR and volumetric analyses yielded 89% and 78% accuracies, respectively. A multi-modality analysis did not generate a higher accuracy (89%). A quantitative anatomically compartmented approach to SPECT analysis yields a particularly high lateralization accuracy in the case of mTLE comparable to that of quantitative FLAIR MR imaging. Hippocampal segmentation in this regard correlates well with ictal origin and shows good reliability in the preoperative analysis.

Topics: Adult; Aged; Cysteine; Dominance, Cerebral; Epilepsy, Post-Traumatic; Epilepsy, Temporal Lobe; Female; Head Injuries, Closed; Hippocampus; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Organ Size; Organotechnetium Compounds; Preoperative Care; Radiopharmaceuticals; Retrospective Studies; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon; Young Adult

Topics: Adult; Electroencephalography; Epilepsy, Temporal Lobe; Fluorodeoxyglucose F18; Humans; Image Interpretation, Computer-Assisted; Magnetic Resonance Imaging; Male; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed

A thirty-seven-year-old man, with temporal epilepsy, had transient, atypical psychiatric states with periods of time without any symptom. These episodes included hypersexuality with qualitative changes of sex drive, obscene behavior, exhibitionism, masturbation and modified sexual orientation. Blunted affect, inability to recognize significant persons (visual agnosia) were also detected. Magnetic resonance imaging was normal and interictal single-photon emission computed tomography (SPECT) showed decreased cerebral perfusion in both temporal lobes.. The principal hypothesis is a Klüver-Bucy syndrome (KBS). In animals and human beings, this syndrome can be produced by bilateral temporal lobectomy. It is characterised by hypersexuality, visual agnosia, strong oral tendency, dietary changes, hypermetamorphosis and blunted affect. A minimum of three KBS elements suggests bilateral temporal dysfunction and supports the diagnosis. The syndrome may occur in herpes encephalitis, head trauma, Pick disease and temporal epilepsy. A single case of a patient, without any evidence for structural lesion in temporal lobes, is presented with many KBS symptoms, behavioral changes being due to complex partial seizure. Bitemporal dysfunction for this patient was confirmed by SPECT scan. On the other hand, the detected behavioral changes cannot be explained by temporal epilepsy alone. Postictal hypersexuality in temporal epilepsy consists in sexual arousal but not sexual aberrations as found in KBS.. KBS following complex partial status epilepticus is a rare phenomenum. The case described here shows how atypical psychiatric episodes can cover complex neurologic disorders.

Topics: Acute Disease; Adult; Arousal; Dominance, Cerebral; Electroencephalography; Epilepsy, Temporal Lobe; Frontal Lobe; Humans; Kluver-Bucy Syndrome; Magnetic Resonance Imaging; Male; Monitoring, Ambulatory; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon

The aims of the present study were to explore the relation between ictal scalp EEG patterns and ictal hyperperfusion patterns in patients with unilateral hippocampal sclerosis-associated mesial temporal lobe epilepsy (HS-MTLE) by using semiquantitative single-photon emission computed tomography (SPECT) analysis and to assess clinical significance of ictal hyperperfusion patterns.. We studied retrospectively 39 consecutive patients with surgically proven HS-MTLE. All had both interictal and ictal SPECTs with the tracer injection during a complex partial seizure (CPS) typical of MTLE semiology. According to initial ictal discharge (IID) frequency on scalp EEG, two lateralizing patterns were identified: (a) a sustained regular 5- to 9-Hz rhythm with a restricted temporal or subtemporal distribution (group 1); and (b) an irregular 2- to 5-Hz rhythm with a widespread distribution (group 2). We performed group analysis by using statistical parametric mapping (SPM) of paired ictal-interictal SPECTs to identify regions of significant ictal hyperperfusion and compared clinical characteristics, tracer-injection time, semiology, pathologic HS grade, and surgical outcome between two groups.. Of the 39 patients, 19 patients (10 males, nine right HS) were designated as group 1, and the remaining 20 patients (eight males, seven right HS), group 2. Group 1 showed hyperperfusion mainly confined to the ipsilateral temporal lobe, whereas group 2 showed widespread hyperperfusion in the extratemporal structures such as ipsilateral basal ganglia, brainstem, and bilateral thalamus, in addition to the ipsilateral temporal lobe. No significant difference was found between two groups in clinical characteristics, injection time, pathologic HS grade, and surgical outcome. Among semiologic features, dystonic limb posturing was more frequently observed in group 2 (p = 0.006).. Scalp EEG IID frequency in HS-MTLE can be an important determining factor of ictal hyperperfusion patterns. The lack of difference in surgical outcome between two groups implies that different hyperperfusion patterns, according to their IID frequencies, reflect only preferential pathways of ictal propagation rather than intrinsic epileptogenic region.

Topics: Adult; Electroencephalography; Epilepsy, Temporal Lobe; Female; Functional Laterality; Hippocampus; Humans; Male; Regional Blood Flow; Retrospective Studies; Sclerosis; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon; Treatment Outcome

We investigated the diagnostic performance of 18F-FDG PET and ictal (99m)Tc-HMPAO SPET in pediatric temporal lobe epilepsy (TLE). Twenty-one pediatric TLE patients were enrolled in this study. Their diagnoses were confirmed by histology and post-surgical outcome (Engel class I or II). The patients' ages were 18 or younger (15+/-3 years). Of the 21 patients, 21 patients underwent 18F-FDG PET scan and 15 underwent ictal (99m)Tc-HMPAO SPET. Preoperative PET and/or ictal SPET images were reviewed by simple visual assessment and by statistical parametric mapping (SPM). Asymmetric indices (AI) were calculated using statistical probabilistic anatomical map (SPAM) on 18F-FDG PET. In nine patients who underwent both ictal and interictal SPET, SISCOM (subtraction ictal SPET coregistered to MR template) was performed. PET correctly localized epileptogenic zones in 20 of 21 (95%) by visual assessment. SPM analysis of PET correctly localized epileptogenic zones in 18 of 21 (86%). Ictal SPET correctly localized epileptogenic zones in 12 of 15 (80%) by visual assessment. SPM analysis of ictal SPET correctly localized epileptogenic zones in 12 of 15 (80%). SISCOM correctly localized 8 of 9 (89%), which was equal to that of visual assessment of ictal SPET. The AIs of the temporal lobes by PET were -15+/-8.4 in the left and 9.9+/-8.9 in the right TLE (normal control: -2.9+/-2.8), and correctly localized epileptogenic zones in all cases. As is found in adult TLE, PET and ictal SPET efficiently localized epileptogenic zones in pediatric TLE. SPM analysis of PET or ictal SPET could be used as an aid to visual assessment. Moreover, SISCOM was equal visual assessment of ictal SPET images in terms of lesion localizations.

Topics: Adolescent; Brain Mapping; Child; Diagnosis, Differential; Epilepsy, Temporal Lobe; Female; Fluorodeoxyglucose F18; Functional Laterality; Humans; Male; Positron-Emission Tomography; Probability; Technetium Tc 99m Exametazime; Tomography, Emission-Computed; Tomography, Emission-Computed, Single-Photon

The goal of neuroimaging in epilepsy is to localize the region of seizure onset. Single-photon emission computed tomography with tracer injection during seizures (ictal SPECT) is a promising tool for localizing seizures. However, much uncertainty exists about how to interpret late injections, or injections done after seizure end (postictal SPECT). A widely available and objective method is needed to interpret ambiguous ictal and postictal scans, with changes in multiple brain regions.. Ictal or postictal SPECT scans were performed by using [99mTc]-labeled hexamethyl-propylene-amine-oxime (HMPAO), and images were analyzed by comparison with interictal scans for each patient. Forty-seven cases of localized epilepsy were studied. We used methods that can be implemented anywhere, based on freely downloadable software and normal SPECT databases (http://spect.yale.edu). Statistical parametric mapping (SPM) was used to localize a single region of seizure onset based on ictal (or postictal) versus interictal difference images for each patient. We refer to this method as ictal-interictal SPECT analyzed by SPM (ISAS).. With this approach, ictal SPECT identified a single unambiguous region of seizure onset in 71% of mesial temporal and 83% of neocortical epilepsy cases, even with late injections, and the localization was correct in all (100%) cases. Postictal SPECT, conversely, with injections performed soon after seizures, was very poor at localizing a single region based on either perfusion increases or decreases, often because changes were similar in multiple brain regions. However, measuring which hemisphere overall had more decreased perfusion with postictal SPECT, lateralized seizure onset to the correct side in approximately 80% of cases.. ISAS provides a validated and readily available method for epilepsy SPECT analysis and interpretation. The results also emphasize the need to obtain SPECT injections during seizures to achieve unambiguous localization.

Topics: Adolescent; Adult; Brain Mapping; Electroencephalography; Epilepsy; Epilepsy, Temporal Lobe; Female; Functional Laterality; Humans; Image Processing, Computer-Assisted; Male; Middle Aged; Neocortex; Preoperative Care; Reproducibility of Results; ROC Curve; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Videotape Recording

The aim of this study was to assess the regional relative interictal and postictal perfusion changes in temporal and parietal lobe epilepsy.. We investigated interictal and postictal magnet resonance perfusion changes in five patients with temporal lobe epilepsy either with hippocampal sclerosis (n = 3) or without (n = 2), and in one patient with extratemporal (parietal lobe) epilepsy. T(2)*-weighted single-shot echo-planar images were acquired after bolus application of 0.2 mmol/kg gadolinium-diethylene triamine pentaacetic acid (GD-DTPA) at baseline and after intervals of 2-12 min, 15-23 min, 28-50 min, 63-72 min, and 180-240 min. The bolus-peak ratio was calculated in regions of interest in the hippocampus (HIP), parahippocampal gyrus (PHG), thalamus (THA), cortex (COR), and white matter (WM), yielding relative perfusion changes.. Interictally, we found relative hyperperfusion of the ictogenic side in five of six patients in the HIP. Postictally, the perfusion decreased in the HIP by 25-39% as compared to baseline, whereas the PHG showed a reverse pattern. In the late postictal phase, perfusion increased in the HIP again and decreased in the PHG. In the THA, the inter- and postictal changes were small (5-19%). COR and WM showed equivocal results.. Postictal relative hypoperfusion in the HIP appears to be associated with the cessation of neuronal ictal discharge, whereas postictal hyperperfusion in the PHG lags behind and may reflect increased metabolism to restore the interictal state of neuronal excitability.

Topics: Adult; Brain; Brain Mapping; Cerebral Cortex; Cerebrovascular Circulation; Echo-Planar Imaging; Epilepsy; Epilepsy, Temporal Lobe; Female; Follow-Up Studies; Gadolinium DTPA; Hippocampus; Humans; Male; Middle Aged; Parahippocampal Gyrus; Parietal Lobe; Regional Blood Flow; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon

Typical (TPP) and atypical (APP) perfusion patterns (PP) may be seen in ictal SPECT of patients with temporal lobe epilepsy (TLE). APP may pose problem in the lateralization of the epileptogenic zone (EZ). We aimed to investigate predictive variables for the occurrence of TPP and APP. Fifty-one TLE patients were submitted to successful anterior-mesial temporal lobectomy. Univariate (UVA) and multivariate (MVA) analysis were performed upon clinical data, distribution of interictal spikes, and ictal chronology of seizures. From MVA, a final predictive model (FPM) was determined to better predict TPP and APP. Forty patients showed TPP (78.5%) and 11 patients APP (21.5%). Accuracy of ictal SPECT was higher in the unilateral (UIS) than in the bilateral (BIS) interictal spikes group (P = 0.05). FPM showed that patients exhibiting BIS, with shorter proportion of the electrographic seizure occurring after completion of tracer injection, and longer clinical than EEG seizure duration had more APP (P = 0.003). Generalized tonic-clonic seizures did not result in more APP. We concluded that analysis of ictal SPECT in TLE requires the knowledge of TPP and APP, the distribution of interictal spikes on temporal lobes and the ictal chronology of seizures. BIS showed that beyond a more complex epileptogenicity and seizure propagation, they may also lead to APP.

Topics: Adolescent; Adult; Electroencephalography; Epilepsy, Temporal Lobe; Female; Functional Laterality; Humans; Image Processing, Computer-Assisted; Logistic Models; Magnetic Resonance Imaging; Male; Middle Aged; Monitoring, Physiologic; Multivariate Analysis; Neuropsychological Tests; Radiopharmaceuticals; Retrospective Studies; Technetium Tc 99m Exametazime; Temporal Lobe; Time Factors; Tomography, Emission-Computed, Single-Photon

Dystonic posturing (DP) is one of the most reliable lateralizing indicators for temporal lobe epilepsy (TLE). We evaluated the ictal hyperperfusional areas in patients with DP by using ictal-interictal subtraction single-photon emission computed tomography (SPECT).. Ninety-seven patients were treated surgically for intractable TLE, and 39 patients underwent ictal and interictal SPECT studies with the same isotope. These patients were divided into three groups: group I with DP of the contralateral side extended to the epileptogenic focus, group II with elevated muscle tonus but without DP, and group III without DP or alteration of muscle tonus. Ictal, interictal SPECT and thin-slice magnetic resonance imaging (MRI) were overlaid by using the automatic multimodality registration program to construct ictal-interictal subtracted images of SPECT on MRI.. Thirteen patients belonged to group I; 14, to group II; and 12, to group III. A statistically significant difference in hyperperfusion rate was observed in the putamen (10 patients in group I, three in group II and two in group III; p < 0.01) and mesial temporal lobe (10 patients in group I, seven in group II, and two in group III; p < 0.05) on the ipsilateral side of the epileptogenic focus. No statistically significant difference was observed for other ictal symptoms except ipsilateral upper-limb automatism (eight patients in group I, three in group II, and none in group III; p < 0.01).. A strong correlation between DP and hyperperfusion in the putamen and mesial temporal lobe was demonstrated. Some patients showed a wide hyperperfusion area extending from the mesial temporal lobe to putamen, which may correspond to the propagation of epileptic discharges. Our results suggest a correlation between hyperperfusion of putamen and contralateral dystonic posturing.

Topics: Adolescent; Adult; Brain Mapping; Child; Dystonia; Epilepsy, Temporal Lobe; Female; Functional Laterality; Humans; Image Processing, Computer-Assisted; Iodine Radioisotopes; Magnetic Resonance Imaging; Male; Middle Aged; Muscle Tonus; Posture; Putamen; Subtraction Technique; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Brain single photon emission computed tomographic (SPECT) images acquired after injecting Tc-99m-HMPAO into the internal carotid artery (ICA) during an intracarotid amobarbital procedure (IAP SPECT) provide anatomical information on the blood flow distribution from the ICA. In this study, probabilistic maps of the distribution of blood supply from the ICA were developed using the IAP SPECT images. Twenty-two sets of basal and IAP SPECT were collected from an existing database. IAP SPECT images were coregistered to basal SPECT images, and spatial normalization parameters used for basal SPECT images were reapplied to IAP SPECT for anatomical standardization. Pixel counts of IAP SPECT images were then normalized, and the probabilistic map of cerebral perfusion distribution (perfusion probabilistic map) for each hemisphere was determined by averaging the spatial/count-normalized IAP SPECT images. Population-based probabilistic maps representing the extent of ICA territory (extent probabilistic map) were also composed by averaging the binary images obtained by thresholding the spatially normalized IAP SPECT images. The probabilistic maps were used to quantify cerebral perfusion and reserve change after arterial bypass surgery in 10 patients with ICA stenosis. In the probabilistic maps, blood supply from the ICA was found to be most likely in the dorsolateral frontal lobe, the anterosuperior portion of the temporal lobe, and in the frontoparietal area. Of the subcortical regions, the striatum was found to be most likely to derive its blood supply from ICA. In patients with cerebral occlusive disease, improvements in basal perfusion and perfusion reserve in the bypass-grafted ICA territory were well identified and were increased by 6.2% and 4.6%, respectively, on average. The probabilistic maps developed in this study illustrate the perfusion distribution and extent of vascular territory for ICA and would be useful for objective evaluations of perfusion status in cerebrovascular disease.

Topics: Adolescent; Adult; Algorithms; Amobarbital; Anterior Temporal Lobectomy; Brain; Carotid Artery, Internal; Carotid Stenosis; Dominance, Cerebral; Epilepsy, Temporal Lobe; Female; Humans; Image Processing, Computer-Assisted; Imaging, Three-Dimensional; Magnetic Resonance Imaging; Male; Models, Statistical; Postoperative Complications; Reference Values; Regional Blood Flow; Retrospective Studies; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Postictal psychosis is a well-known complication, occurring especially in patients with temporal lobe epilepsy. It usually runs a benign course. The literature on this topic is sparse, and the underlying pathogenic mechanisms are not known.. We report five patients with temporal lobe epilepsy in whom postictal psychosis developed during the course of video-EEG monitoring; they were studied with hexamethyl-propyleneamine-oxime single-photon emission computed tomography (HMPAO-SPECT) during and after the psychotic event.. In comparison to the interictal state, all SPECT scans obtained during postictal psychosis were remarkable for bifrontal and bitemporal hyperperfusion patterns. Some studies also demonstrated unilateral left lateral frontal hyperperfusion. These cortical blood-flow patterns appeared to be distinct from those obtained during complex partial seizures.. Our data suggest that postictal psychoses in patients with temporal lobe epilepsy are associated with hyperactivation of both temporal and frontal lobe structures. This hyperperfusion may reflect ongoing (subcortical) discharges, active inhibitory mechanisms that terminate the seizure, or simply a dysregulation of cerebral blood flow.

Topics: Adult; Dominance, Cerebral; Electroencephalography; Epilepsy, Complex Partial; Epilepsy, Temporal Lobe; Female; Frontal Lobe; Humans; Hyperemia; Male; Monitoring, Physiologic; Neurocognitive Disorders; Risk Factors; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon; Video Recording

Intermittent photic stimulation (IPS) may produce epileptiform discharges and seizures, most of which are generalized. There are several cases of focal seizures of occipital origin induced by IPS and only five reported cases originating from the temporal lobe (TL). We report an unusual case of TL epilepsy, supported by electroclinical and neuroimaging data, with rhythmic focal TL discharges precipitated by photic stimulus.. A 37 year old male with refractory epilepsy due to a right mesial temporal sclerosis presented a focal right TL photoparoxysmal response during IPS. A routine, interictal SPECT study obtained with injection of HMPAO, carried out during continuous pulses of the photic stimulus at 16 Hz, disclosed hyperperfusion over the right TL. Presurgical ictal studies demonstrated seizures arising from the same region. A temporal lobectomy rendered the patient seizure-free and further EEGs with IPS were normal.. To our knowledge, this is the sixth case in medical literature showing evidence of photosensitivity associated with a TL lesion and it is the first in which photic stimulation induced a focal electrographic response of the involved TL. We hypothesize that in rare cases, photosensitivity may be related to a mesial TL lesion without occipital cortex involvement.

Topics: Adult; Cerebrovascular Circulation; Electroencephalography; Epilepsy, Reflex; Epilepsy, Temporal Lobe; Humans; Male; Memory; Neuropsychological Tests; Neurosurgical Procedures; Photic Stimulation; Radiopharmaceuticals; Sclerosis; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon

Tc-99m HMPAO single photon emission computed tomography was performed in a patient who had experienced aphasia for 3 days. The patient had a medical history of subarachnoid hemorrhage and intracranial hemorrhage. Both of these hemorrhages were related to a dural arteriovenous malformation that was embolized after the onset of the cerebral vascular events. Focal hyperperfusion was seen in the left temporal lobe adjacent to a perfusion defect corresponding to the old cerebral hemorrhage. The finding was interpreted as the focus of the patient's epilepsy. His aphasia resolved after the administration of anticonvulsant medication for several days.

Topics: Aphasia; Arteriovenous Malformations; Brain; Cerebral Arteries; Cerebral Veins; Epilepsy, Temporal Lobe; Humans; Intracranial Embolism; Male; Middle Aged; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Most of the literature concerning interictal SPECT brain scanning in patients with seizures has involved the evaluation of those with temporal lobe epilepsy. The authors' aim was to determine the utility of interictal SPECT in patients with neocortical epilepsy.. Eighty-four patients with neocortical epilepsy were evaluated with 95 interictal SPECT scans and magnetic resonance imaging (MRI).. Fifty-four percent of studies with normal MRI findings had SPECT images without regions of hypoperfusion. Sixty-one percent of patients with abnormal MRI results had matching defects visible on SPECT images. Fourteen scans (only 24%) had focal hypoperfusion by SPECT and no obvious matching MRI finding.. Interictal SPECT, without a comparison ictal study, is of potentially limited value in localizing neocortical seizure foci. SPECT findings usually match MRI findings. Interictal SPECT, however, may still be of value in confirming abnormalities detected by ictal examination.

Topics: Adolescent; Adult; Child; Child, Preschool; Cysteine; Epilepsy; Epilepsy, Temporal Lobe; Female; Follow-Up Studies; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Neocortex; Organotechnetium Compounds; Radiopharmaceuticals; Retrospective Studies; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

We examined diagnostic performances of Tc-99m hexamethylpropylene amine oxime (HMPAO) and Tc-99m electron capture detection (ECD) ictal single-photon emission computed tomography (SPECT) to localize the epileptogenic zones in mesial temporal lobe epilepsy (TLE) and neocortical epilepsy (NE).. Epileptogenic zones were identified by invasive EEG or surgical outcome. Ictal SPECT was performed with stabilized Tc-99m HMPAO (TLE, 17; NE, 23) and with Tc-99m ECD (TLE, 7; NE, 7). Single-blind visual interpretation was used to localize the epileptogenic zones. Asymmetric index was calculated. Subtraction ictal SPECT was coregistered to a magnetic resonance imaging (MRI) template.. In TLE, the sensitivity of Tc-99m HMPAO SPECT was 82% (14 of 17) and that of Tc-99m ECD SPECT was 71% (five of seven). The asymmetric index (AI; 25 +/- 10) of Tc-99m HMPAO SPECT was larger (p = 0.05) than the AI (13 +/- 13) of Tc-99m ECD SPECT in patients with TLE. In NE, the sensitivity of Tc-99m HMPAO SPECT was 70% (16 of 23), but that of Tc-99m ECD SPECT was 29% (two of seven). The AI (15 +/- 10) of Tc-99m HMPAO SPECT was significantly larger (p = 0.02) than the AI (4.8 +/- 6) of Tc-99m ECD SPECT in patients with NE. Subtraction ictal SPECT coregistered to MRI supported the visual assessment.. We concluded that the sensitivity of Tc-99m ECD ictal SPECT is similar to that of Tc-99m HMPAO ictal SPECT in TLE; however, ictal hyperperfusion was higher with the Tc-99m HMPAO SPECT. In patients with NE, Tc-99m HMPAO ictal SPECT also was superior to Tc-99m ECD ictal SPECT in sensitivity and degree of hyperperfusion.

Topics: Adult; Cerebrovascular Circulation; Epilepsy; Epilepsy, Temporal Lobe; Female; Humans; Male; Neocortex; Radiopharmaceuticals; Sensitivity and Specificity; Technetium Tc 99m Exametazime; Time Factors; Tomography, Emission-Computed, Single-Photon

Inadequate sodium amytal delivery to the posterior hippocampus during the intracarotid Wada test has led to development of selective tests. Our purpose was to show the sodium amytal distribution in the posterior cerebral artery (PCA) Wada test and to relate it to functional deficits during the test. We simultaneously injected 80 mg sodium amytal and 14.8 MBq 99mTc-hexamethylpropyleneamine oxime (HMPAO) into the P2-segment of the PCA in 14 patients with temporal lobe epilepsy. To show the skull, we injected 116 MBq 99mTc-HDP intravenously. Sodium amytal distribution was determined by high-resolution single-photon emission computed tomography (SPECT). In all patients, HMPAO was distributed throughout the parahippocampal gyrus and hippocampus; it was also seen in the occipital lobe in all cases and in the thalamus in 11. Eleven patients were awake and cooperative; one was slightly uncooperative due to speech comprehension difficulties and perseveration. All patients showed contralateral hemianopia during the test. Four patients had nominal dysphasia for 1-3 min. None developed motor deficits or had permanent neurological deficits. Neurological deficits due to inactivation of extrahippocampal areas thus do not grossly interfere with neuropsychological testing during the test.

Topics: Adult; Amobarbital; Aphasia; Brain; Epilepsy, Temporal Lobe; Female; Hemianopsia; Humans; Injections, Intra-Arterial; Male; Memory; Memory Disorders; Middle Aged; Posterior Cerebral Artery; Postoperative Complications; Psychomotor Performance; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

We report a case of successful radiosurgical treatment of lesional epilepsy of mesial temporal origin. A patient presented with a 2-year history of medically intractable complex partial seizures associated with a mesial temporal angioma. Interictal scalp EEG and MEG showed focal epileptiform activity around the lesion. 99mTc-HMPAO-SPECT and 18F-FDG-PET demonstrated depressed blood flow and glucose metabolism in the corresponding temporal lobe. The patient underwent gamma knife radiosurgery for the causative lesion with a low marginal dose of 18 Gy. After treatment, the partial attack ceased without shrinkage of the lesion or peri-lesional parenchymal radiation injury.

Topics: Adult; Brain Neoplasms; Electroencephalography; Epilepsy, Temporal Lobe; Female; Fluorodeoxyglucose F18; Hemangioma; Humans; Magnetic Resonance Imaging; Magnetoencephalography; Radiopharmaceuticals; Radiosurgery; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed; Tomography, Emission-Computed, Single-Photon; Treatment Outcome

Factors affecting blood flow observed by interictal single-photon emission computed tomography (SPECT) images in temporal lobe epilepsy (TLE) have not been systematically studied or consistently demonstrated. We evaluated interictal SPECT results with respect to many clinical variables in a large population of TLE patients, all of whom underwent temporal lobectomy.. Interictal 99mTc-HMPAO SPECT scans from 61 TLE patients were obtained before an anterior temporal lobectomy. SPECT was analyzed using a region of interest analysis (ROI) in the cerebellum, anterior temporal lobe, lateral temporal lobe, mesial temporal lobe, whole temporal lobe, and inferior frontal lobe. Asymmetry indices (AIs) were calculated. Correlative analysis of AIs and clinical variables was performed.. The AIs from TLE patients differed significantly from those of controls in the anterior temporal (p < 0.01), lateral temporal (p < 0.001), and whole temporal (p < 0.01) regions. No consistent overall correlation between the AIs and clinical variables existed. In right TLE (RTLE) only, AIs in the lateral and whole temporal lobe were positively correlated with age of onset (r = 0.470, p < 0.05; r = 0.548, p < 0.01, respectively). Similarly, in RTLE only, duration of epilepsy was negatively correlated with the anterior (r = -0.395, p < 0.05) and mesial (r = -0.45, p < 0.05) temporal lobe AI. No correlations were found between clinical variables and AIs in left TLE (LTLE) patients.. Significant correlation of age at onset and duration of epilepsy with AIs in RTLE but not LTLE suggests physiologic processes may be determined in part by laterality of TLE. Clinical applications are problematic.

Topics: Adult; Age of Onset; Cerebellum; Epilepsy, Temporal Lobe; Female; Frontal Lobe; Functional Laterality; Humans; Male; Technetium Tc 99m Exametazime; Temporal Lobe; Time Factors; Tomography, Emission-Computed, Single-Photon; Treatment Outcome

High-resolution magnetic resonance imaging (MRI) plays a crucial role in the presurgical evaluation of patients with medically refractory partial epilepsy. Although MRI detects a morphologic abnormality as the cause of the epilepsy in the majority of patients, some patients have a normal MRI. This study was undertaken to explore the hypothesis that in patients with normal MRI, invasive monitoring can lead to localization of the seizure-onset zone and successful epilepsy surgery.. A series of 115 patients with partial epilepsy who had undergone intracranial electrode evaluation (subdural strip, subdural grid, and/or depth electrodes) between February 1992 and February 1999 was analyzed retrospectively. Of these, 43 patients (37%) had a normal MRI.. Invasive monitoring detected a focal seizure onset in 25 (58%) patients, multifocal seizure origin in 12 (28%) patients, and in six patients, no focal seizure origin was found. Of the 25 patients with a focal seizure origin, cortical resection was performed in 24, of whom 20 (83%) had a good surgical outcome with respect to seizure control. Six of the 12 patients with multifocal seizure origin underwent other forms of epilepsy surgery (palliative cortical resection in two, anterior callosotomy in two, and vagal nerve stimulator placement in two).. Successful epilepsy surgery is possible in patients with normal MRIs, but appropriate presurgical evaluations are necessary. In patients with evidence of multifocal seizure origin during noninvasive evaluation, invasive monitoring should generally be avoided.

Topics: Adolescent; Adult; Cerebral Cortex; Electrodes, Implanted; Electroencephalography; Epilepsies, Partial; Epilepsy, Frontal Lobe; Epilepsy, Temporal Lobe; Female; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Preoperative Care; Retrospective Studies; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Treatment Outcome

To elucidate uncoupling of perfusion and metabolism and its significance in epilepsy, 15O water and 18F fluorodeoxyglucose (FDG) positron emission tomography (PET) and Tc-99m hexamethyl-propyleneamine-oxime (HMPAO) single-photon emission computed tomography (SPECT) were examined by SPM (statistical parametric mapping) and quantitation by using SPAM (statistical probabilistic anatomic map).. [15O]water and [18F]FDG-PET, and [99mTc]-HMPAO SPECT were performed in 25 patients (SPECT in 17 of 25) with medial temporal lobe epilepsy. For volume of interest (VOI) count analysis, the normalized counts using VOI based on SPAM templates of PET and SPECT were compared with those of the normal controls. Perfusion or metabolism was found abnormal if the Z score was >2 for each VOI. For SPM analysis, the differences between each patient's image and a group of normal control images (t statistic for p < 0.01) on a voxel-by-voxel basis were examined to find significant decreases in perfusion or metabolism.. With SPAM VOI count analysis, areas of hypoperfusion were found in 13 patients in the epileptogenic temporal lobes by [15O]water PET and areas of hypometabolism in 21 patients by [18F]FDG-PET. With voxel-based SPM analysis, the epileptogenic zones were localized in 15 by [15O]water PET and in 23 patients by [18F]FDG-PET. The localization by [15O]water PET was concordant with that of [18F]FDG-PET. The areas of hypoperfusion on [15O]water PET were absent or smaller than the areas of hypometabolism on [18F]FDG-PET. Interictal [99mTc]-HMPAO SPECT revealed the hypoperfused zones in seven of 17 patients on visual assessment.. SPAM VOI count and SPM analysis of [15O]water and [18F]FDG-PET and [99mTc]-HMPAO SPECT revealed that in the same patients, the areas of hypoperfusion were concordant with but smaller than the areas of hypometabolism. Discordance of perfusion and metabolic abnormalities represents an uncoupling of perfusion and metabolism in the epileptogenic zones, and this might explain the lower diagnostic accuracy of perfusion imaging in temporal lobe epilepsy.

Topics: Adolescent; Adult; Data Interpretation, Statistical; Epilepsy, Temporal Lobe; Female; Fluorodeoxyglucose F18; Glucose; Humans; Linear Models; Male; Middle Aged; Oxygen Radioisotopes; Regional Blood Flow; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed; Tomography, Emission-Computed, Single-Photon; Water

To analyze the relationship between ictal electroencephalography (EEG) and ictal single-photon emission computed tomography (SPECT) and to evaluate the diagnostic usefulness of ictal SPECT as an independent presurgical evaluation technique.. Sixty-eight patients with temporal lobe epilepsy who underwent temporal lobectomy with good surgical outcome were included in this study. Ictal SPECT was performed during video-EEG monitoring. The ictal EEG was analyzed in 5-second intervals from the initiation of the ictal rhythm. Lateralized EEG dominance was determined by the amplitude, frequency, or regional patterns of ictal rhythm for each 5-second interval. The total ictal EEG was divided into three periods: preinjection (maximum, 30 seconds), the initial part of the postinjection period (30 seconds), and the latter part of the postinjection period (30 to 60 seconds). The results of ictal SPECT were compared with the lateralized EEG dominance of each period and at seizure onset.. Fifty-four of 68 ictal EEGs correctly lateralized seizure focus ipsilateral to the side of surgery. Ictal SPECT correctly lateralized the epileptogenic temporal lobe in 61 of 68 patients (mean injection time, 29.8 seconds from onset). Multivariate analysis indicated that only the EEG dominance of the preejection period correlated significantly with the concordant hyperperfusion of ictal SPECT. Correct lateralization of ictal SPECT occurred in 10 of 14 patients with nonlateralized ictal EEG.. Preinjection neuronal activity seems to be important for the accurate interpretation of the hyperperfused patterns of ictal SPECT. Ictal SPECT is an independent and confirmatory presurgical evaluation technique.

Topics: Adult; Brain; Cerebrovascular Circulation; Electroencephalography; Epilepsy, Temporal Lobe; Follow-Up Studies; Functional Laterality; Humans; Monitoring, Physiologic; Multivariate Analysis; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon; Videotape Recording

For evaluation of potential functional deficits, an intraarterial amobarbital test is performed prior to neurosurgical or neuroradiological interventions. To visualize individual amobarbital perfusion patterns, simultaneous injection of (99m)Tc-HMPAO was performed previously. The present study describes for the first time a method of coregistration of intraarterial SPECT during selective amobarbital test to MRI. Three patients undergoing selective amobarbital test of the posterior cerebral artery were included. SATSCOM (Selective amobarbital test intraarterial SPECT coregistered to MRI) was performed by skull extraction in SPECT and MRI followed by surface matching. In all three patients, SATSCOM revealed accurate matching results. With this functional-anatomical mapping, suppression of higher cortical functions can be correlated to anatomical regions. Furthermore, a more precise mapping of amobarbital effect improves planning invasive interventions, particularly those close to eloquent areas.

Topics: Adult; Amobarbital; Brain Mapping; Cerebral Cortex; Dominance, Cerebral; Epilepsy, Temporal Lobe; Female; Hippocampus; Humans; Image Processing, Computer-Assisted; Injections, Intra-Arterial; Magnetic Resonance Imaging; Male; Mental Recall; Middle Aged; Postoperative Complications; Psychosurgery; Regional Blood Flow; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon

Image processing techniques were applied to interictal positron emission tomography (PET) and single-photon emission computed tomography (SPECT) brain images to aid in the localization of epileptogenic foci by calculating a functional image that represents the degree of coupling between perfusion and metabolism. Uncoupling of these two functions has been demonstrated to be a characteristic of epileptogenic tissue in temporal lobe epilepsy and has the potential to serve as a diagnostic measure for localization in other areas as well.. Interictal PET ((18)F-FDG) and interictal SPECT ((99m)Tc-HMPAO) scans were acquired from 11 epilepsy patients. The metabolism and perfusion images were three-dimensionally spatially registered, and a functional ratio-image was computed. These functional maps are overlaid onto a three-dimensional rendering of the same patient's magnetic resonance imaging anatomy.. In all patients, an average uniform perfusion-to-metabolism ratio showed approximately constant values throughout most of the whole brain. However, the epileptogenic area (confirmed on surgery) demonstrated an area of elevated perfusion/metabolism in the grey matter.. Although hypometabolism in the PET image was observed in most of these patients, the calculation of a functional ratio-image demonstrated localized foci that in some cases could not be observed on the PET image alone. The ratio-image also yields a quantitative measure of the uncoupling phenomenon.

Topics: Adolescent; Adult; Brain; Brain Mapping; Data Interpretation, Statistical; Epilepsy; Epilepsy, Temporal Lobe; Female; Fluorodeoxyglucose F18; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Regional Blood Flow; Technetium Tc 99m Exametazime; Tomography, Emission-Computed; Tomography, Emission-Computed, Single-Photon

The goal of this study was to determine whether regional cerebral blood flow (rCBF) changes that were found contralaterally to a verified unilateral epileptic focus were associated with the spatiotemporal organization of epileptic abnormalities.. The CBF in both hippocampi was assessed using stable Xe-enhanced computerized tomography in a series of 19 patients with unilateral mesiotemporal epilepsy. Results were compared according to the distribution of interictal spiking and the spatiotemporal organization of the ictal discharges as determined by stereoelectroencephalography. Two groups were defined: in Group 1 (nine patients), the discharge remained unilateral; in Group 2 (10 patients), the discharge spread to contralateral mesiotemporal structures. For Group 1, the rates of ipsi- and contralateral hippocampal blood flow (HBF) were 32.88+/-15.53 and 45.88+/-17.19 ml/100 g/minute, respectively, whereas in Group 2 they were 36.7+/-11.54 and 36.4+/-11.27 ml/100 g/minute (mean+/-standard deviation). A two-way analysis of variance combining type of seizure (Group 1 compared with Group 2) and HBF (ipsi- compared with contralateral absolute values) demonstrated a main effect for HBF (F[1,17] = 5.051; p = 0.0382), a significant interaction between the two factors (F[1,17] = 6.188; p = 0.0235), and no main effect for type of seizure (F[1,17] = 0.258; p = 0.6178).. In unilateral mesiotemporal epilepsy, asymmetrical interictal hippocampal perfusion was correlated with restricted unilateral ictal discharges, whereas bilateral hippocampal hypoperfusion was correlated with ictal discharges spreading to the contralateral mesiotemporal structures. The lack of correlation between the degree of hypoperfusion and the percentage of neuron cell loss indicated that the decrease in rCBF has both functional and lesional origins.

Topics: Adolescent; Adult; Electroencephalography; Epilepsy, Temporal Lobe; Hippocampus; Humans; Middle Aged; Radiopharmaceuticals; Regional Blood Flow; Stereotaxic Techniques; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed; Xenon

Because the main blood supply to the medial temporal region is through the posterior cerebral artery, the validity of the intracarotid amobarbital procedure (IAP) is still debated. To verify clinical validity of the IAP, we investigated changes in neuronal function in the medial temporal region during IAP.. Brain single photon emission computed tomography (SPECT) was performed during IAP (IAP-SPECT) in 22 patients with temporal lobe epilepsy (TLE), and regional cerebral blood flow (rCBF) in the medial and lateral temporal regions of interest (ROIs) was measured quantitatively. To determine the distribution of sodium amobarbital, in another 20 patients with TLE, SPECT images were obtained after intracarotid injection of 99mTc-HMPAO mixed with sodium amobarbital.. Mean rCBF was 89.2% in the medial temporal region and 81.6% in the lateral temporal region: in the former region, it was significantly lower than that shown by the results of interictal SPECT (99.1%; p < 0.001). In a few patients, however, rCBF did not decrease in the medial temporal region. In only 25% of patients, the medial temporal region was visualized in SPECT images obtained after intracarotid injection of 99mTc-HMPAO.. The results in this study demonstrate that IAP is valid because the medial temporal region is inactivated in spite of infrequent delivery of sodium amobarbital. We assume that intratemporal diaschisis is operating for the inactivation of neuronal function. IAP-SPECT with intratemporal ROIs may be useful for monitoring changes in neuronal function in the medial temporal region during IAP.

Topics: Adolescent; Adult; Amobarbital; Carotid Arteries; Dominance, Cerebral; Epilepsy, Temporal Lobe; Female; Humans; Hypnotics and Sedatives; Injections, Intra-Arterial; Male; Memory; Middle Aged; Regional Blood Flow; Speech; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon

The distribution of sodium amytal and its effect on regional cerebral perfusion during the intracarotid amytal (Wada) test were investigated using high-resolution hexamethyl propyleneamine oxime (HMPAO) SPECT coregistered with the patient's MRI dataset.. Twenty patients underwent SPECT after intravenous HMPAO injection, and 5 patients had both intravenous and intracarotid injections in a double injection-acquisition protocol.. All patients had hypoperfusion in the territories of the anterior and middle cerebral arteries. Basal ganglia perfusion was preserved in 20 of 25 patients. Hypoperfusion of the entire mesial temporal cortex was seen in 9 of 25 patients. Partial hypoperfusion of the whole mesial cortex or hypoperfusion of part of the mesial cortex was seen in 14 of 25 patients. In 2 of 25 patients, mesial temporal perfusion was unaffected. In 5 patients, the double acquisition showed a distribution of HMPAO delivery matching that of hypoperfusion, except for the following: (a) HMPAO was delivered to the basal ganglia and insula, where there was no hypoperfusion; (b) HMPAO was not delivered to the contralateral cerebellum, which did show hypoperfusion; and (c) in 1 patient, perfusion of the mesial temporal cortex was preserved despite intracarotid delivery of HMPAO.. Some degree of hypoperfusion of medial temporal structures occurs in the great majority of patients during the Wada test. Partial inactivation of memory structures is therefore a credible mechanism of action of the test. The double acquisition protocol provided no evidence that mesial temporal structures are inactivated remotely by diaschisis. Perfusion in the basal ganglia and insular cortex is not affected by amytal.

Topics: Adult; Amobarbital; Carotid Artery, Internal; Cerebrovascular Circulation; Epilepsy, Temporal Lobe; Humans; Injections, Intra-Arterial; Injections, Intravenous; Magnetic Resonance Imaging; Neuropsychological Tests; Preoperative Care; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon

To relate functional effects on the hippocampus during the intracarotid amobarbital test (IAT) to its direct perfusion with amobarbital.. In 17 patients with intractable temporal lobe epilepsy, 28 hemispheres were perfused with 2.3 mL of 10% solution of 200 mg amobarbital and 37 MBq 99mTc-hexamethylpropylene amine oxime (HMPAO). For evaluation of amobarbital effects, data were combined from stereo-EEG (S-EEG) recordings from intrahippocampal depth electrodes and high-resolution SPECT after intracarotid injection of HMPAO.. Perfusion of the entire hippocampus was observed only in hemispheres with a fetal origin of the posterior cerebral artery (PCA). In 10 hemispheres, S-EEG recordings could not unequivocally be assigned to either the anterior or the posterior part of the hippocampus. In the remaining 18 hemispheres, only the two with a fetal type of PCA showed perfusion of the entire hippocampus. In both, hippocampal electrical activity changed under the influence of amobarbital but did not differ in anterior and posterior contacts. In 15 of 16 hemispheres in which SPECT demonstrated perfusion of the anterior hippocampus only, amobarbital injection resulted in significant S-EEG activity change in both the anterior and the posterior parts of the hippocampus.. S-EEG effects on the posterior hippocampus during the IAT can occur without direct perfusion of those brain areas.

Topics: Adolescent; Adult; Amobarbital; Carotid Arteries; Child; Electroencephalography; Epilepsy, Temporal Lobe; Female; Functional Laterality; Hippocampus; Humans; Magnetic Resonance Imaging; Male; Neuropsychological Tests; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

To evaluate the accuracy, feasibility and clinical value of both ictal and interictal 99mTc-ethyl cysteinate dimer (ECD) single photon emission computed tomography (SPECT) in patients with medically refractory epilepsy.. The study included 75 consecutive patients, 48 with temporal lobe epilepsy (TLE group), and 27 with extratemporal epilepsy (ExT group). The accuracy of SPECT was analyzed considering the final diagnosis reached by convergence of clinical, electrophysiologic, structural, pathologic and outcome data.. Ictal SPECT correctly identified the epileptogenic zone in 21 (91.3%) of 23 patients, whereas interictal SPECTs could correctly identify the epileptogenic zone in only 41 (62.1%) of 66 patients (chi2 = 5.56, df = 1, p < 0.05). Results were similar when the two study groups were analyzed separately. Moreover, ictal studies had significantly higher specificity (91.3 vs. 60.6%) and positive predictive value (91.3 vs. 66.2%) than interictal studies for the whole series of patients. Considering all tools used in the preoperative workup of these patients, ictal SPECT significantly contributed to the final topographic diagnosis in seven of 14 patients from TLE group and in six of nine patients from the ExT group. In these patients, ictal SPECT either obviated the need for invasive EEG or helped to define where to concentrate the efforts of invasive investigation.. These data demonstrate that ictal SPECT can be easily achieved by using 99mTc-ECD and can accurately localize the epileptogenic zone in both temporal and extratemporal epilepsies. Ictal ECD SPECT proved to be significantly more sensitive and specific than interictal ECD SPECT, and clinically useful in the definition of the epileptogenic zone.

Topics: Algorithms; Cerebral Cortex; Cysteine; Decision Trees; Electroencephalography; Epilepsy; Epilepsy, Temporal Lobe; Humans; Magnetic Resonance Imaging; Organotechnetium Compounds; Predictive Value of Tests; Radiopharmaceuticals; Sensitivity and Specificity; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Ictal vomiting represents a rare clinical manifestation during seizures originating from the temporal lobes of the nondominant hemisphere. The precise anatomic structures responsible for generation of ictal vomiting remain to be clarified. Ictal single photon emission computed tomography (SPECT), which allows one to visualize the three-dimensional dynamic changes of regional cerebral blood flow (rCBF) associated with the ongoing epileptic activity, should be useful to study the brain areas activated during ictal vomiting.. We performed ictal Tc-HMPAO SPECT scans in two patients with mesial temporal lobe epilepsy (MTLE) whose seizures were characterized by ictal retching and vomiting. MTLE was documented by typical clinical seizure semiology, interictal and ictal EEG findings, hippocampal atrophy on magnetic resonance imaging (MRI) scan, and a seizure-free outcome after selective amydalohippocampectomy. In both patients, seizures originated in the nondominant temporal lobe. We obtained accurate anatomic reference of rCBF changes visible on SPECT by a special coregistration technique of MRI and SPECT. We used ictal SPECT studies in 10 patients with MTLE who had seizures without ictal vomiting as controls.. In the two patients with ictal vomiting, we found a significant hyperperfusion of the nondominant temporal lobe (inferior, medial, and lateral superior) and of the occipital region on ictal SPECT. In patients without ictal vomiting, on the contrary, these brain regions never were hyperperfused simultaneously.. Ictal SPECT provides further evidence that activation of a complex cortical network, including the medial and lateral superior aspects of the temporal lobe, and maybe the occipital lobes, is responsible for the generation of ictal vomiting.

Topics: Adult; Cerebrovascular Circulation; Epilepsy, Temporal Lobe; Female; Functional Laterality; Humans; Magnetic Resonance Imaging; Occipital Lobe; Regional Blood Flow; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon; Vomiting

The aim of our work was to identify clinical and electroencephalographic factors that are statistically correlated to 99mTc HMPAO hypofixation in cryptogenic temporal lobe epilepsy. We selected a homogeneous group of patients (28 males and 17 females) affected by temporal lobe epilepsy and having normal results on computed tomography and magnetic resonance imaging. Patients were classified according to semeiological characteristics of the seizures, presence or absence of spikes on electroencephalography (EEG), age at onset, illness duration, and drug resistance. The presence of focal interictal spikes on EEG was statistically correlated to 99mTc HMPAO temporal hypofixation (p = 0.04). The other electroclinical factors considered in this series did not play an important role in modifying radiopharmaceutical fixation in focal epilepsy in interictal phase. We speculate that a possible explanation for focal radiopharmaceutical hypofixation, in addition to hypoperfusion, is an increased permeability of the blood-brain barrier (due to perivascular inflammation or other causes) which can be responsible for 99mTc HMPAO escape with a resultant hypofixation.

Topics: Adolescent; Adult; Aged; Electroencephalography; Epilepsy, Temporal Lobe; Female; Humans; Male; Middle Aged; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Reading epilepsy is an uncommon epileptic syndrome preferentially related to the temporoparietal region of the language dominant hemisphere. We report ictal and interictal brain perfusion SPECT images in a 28-year-old woman who was reading epilepsy.

Topics: Adult; Brain; Dominance, Cerebral; Epilepsy; Epilepsy, Temporal Lobe; Female; Humans; Language; Radiopharmaceuticals; Reading; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

To compare published fractional rate constants of I-123-Iomazenil (IMZ) and C-11-Flumazenil (three-compartment/four-parameter model) with a I-123-Iomazenil receptor index calculated from two SPECT acquisitions and to compare the receptor index of the epileptogenic area with the contralateral side in patients with unilateral temporal lobe epilepsies.. 28 patients were studied. 13/28 patients had a drug-resistant unilateral temporal lobe epilepsy with a successful focus localisation performed by an extensive video/EEG monitoring. 15 other patients with clinically suspected focal epilepsy and a normal MRI and IMZ SPECT scanning were used as controls. SPECT scanning was performed in all patients 15 and 100 min after intravenous injection of 111 MBq IMZ and 10 min after application of 740 MBq Tc-99m-HMPAO. Quantification of the regional uptake was performed using ROI-technique and the specific and non-specific binding of IMZ was calculated. The receptor index was calculated by the difference of the specific binding from 15 to 100 min p.i. divided by the time interval.. The receptor index showed a linear correlation with recently published fractional rate constants k3 (r = 0.69 and 0.67; p = 0.15) and a moderate correlation with the k4 constant (-0.53 and -0.43; p = 0.28) by the means of C-11-Flumazenil PET and I-123-Iomazenil SPECT studies, respectively. However, statistical significance was not reached due to the few data points available from the published reports. Furthermore, the IMZ receptor index was lower in the epileptogenic area of patients with unilateral temporal lobe epilepsies compared with their contralateral side (p = 0.02; Wilcoxon-test). The IMZ receptor index showed a weak correlation with the regional cerebral blood flow independent of the evaluated region (r < 0.4; p < 0.05).. The IMZ receptor index indicated to be a simple routine approach to estimate the fractional rate constant k3 (r = 0.67). The lower value of the receptor index within the epileptogenic area might be due to a lower receptor density. However in further studies, IMZ might be a helpful tool to find out subtle changes of the receptor affinity due to its approximately 30-fold higher ligand-receptor affinity compared to C-11-Flumazenil.

Topics: Adult; Brain; Cerebrovascular Circulation; Electroencephalography; Epilepsy, Temporal Lobe; Female; Flumazenil; Humans; Iodine Radioisotopes; Magnetic Resonance Imaging; Male; Models, Neurological; Radiopharmaceuticals; Receptors, GABA-A; Regression Analysis; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon; Video Recording

Episodic nocturnal wandering is rare and thought to be an atypical form of nocturnal epilepsy which is responsive to anticonvulsant therapy. We report a case of adult-onset episodic sleep-walking and daytime complex visual hallucination. Ambulatory EEG recordings suggested that both events were ictal phenomenon. Interictal sphenoidal EEG and SPECT studies revealed an epileptogenic focus in the left anterior temporal lobe. During the nocturnal wanderings, the patient had bizarre but non-violent behaviour, and was at risk of minor or severe injury to himself. Both events were completely controlled by carbamazepine for a follow-up period of 8 years. The present case further supports the notion that episodic nocturnal wandering represents an unusual type of nocturnal complex partial seizures.

Topics: Adult; Cerebral Cortex; Diagnosis, Differential; Dominance, Cerebral; Electroencephalography; Epilepsy, Temporal Lobe; Follow-Up Studies; Hallucinations; Humans; Male; Monitoring, Physiologic; Somnambulism; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon; Visual Perception

Single photon emission computed tomography (SPECT) is used as an adjunctive method in preoperative localization of epileptic foci. In temporal lobe epilepsy (TLE), interictal hypoperfusion is observed in 60-70% of cases. Correlation with ictal EEG changes is observed in approximately 50-60% of cases. Relationships with interictal EEG have been studied less. We compared interictal SPECT data obtained in 20 patients with their interictal intracerebral electrical activity recorded by depth electrodes to evaluate a potential relationship.. We studied 20 sequential patients whose clinical, surface, and depth EEG data indicated seizure originating in the temporal lobe and who had interictal [99mTc]hexamethylpropylene amine oxime (HMPAO)-SPECT stereo-EEG (SEEG). Intracerebral electrodes were placed according to the patient's profile. The interictal extent of epileptiform activity allowed delineation of the irritative zone. Interictal spike frequency was also analyzed semiquantitatively. Visual and numerical SPECT analysis was performed blind to SEEG data.. Interictal hypoperfusion was observed in 16 patients, involving the epileptogenic temporal lobe in 14. Except for 1 patient who manifested lateral temporal hypoperfusion corresponding to a mass lesion, two distinctive patterns of hypoperfusion were noted: (a) mesial hypoperfusion (5 patients), and (b) global temporal hypoperfusion (8 patients). In 8 patients, hypoperfusion had also extended into the adjacent cortex. Temporal mesial hypoperfusion was associated with spiking limited to the mesial structures, whereas global temporal hypoperfusion or hypoperfusion extending beyond the temporal lobe was associated with a similar topographic pattern of spikes.. Comparison between SPECT and SEEG data collected in the interictal phase indicated that the extent of the hypoperfused area correlated topographically with that of the underlying irritative zone.

Topics: Adolescent; Adult; Age of Onset; Brain; Brain Mapping; Child; Electrodes, Implanted; Electroencephalography; Epilepsy, Temporal Lobe; Female; Functional Laterality; Humans; Male; Middle Aged; Regional Blood Flow; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon

Selective amobarbital tests with selective temporary inactivation of the left frontal operculum and/or the left parietotemporal cortex were performed in 5 patients with left-hemispheric epileptogenic lesions in or adjacent to classical Broca's and/or Wernicke's area. The aim was to assess language functions in these brain regions before surgery, to tailor the surgery according to the individual functional importance of these brain regions, and to predict postoperative outcome.. Amobarbital was injected by transfemoral selective catheterization of the arteries supplying the target areas. Along with neuropsychological and neurological testing during the amobarbital procedure, EEG recordings were performed in all patients, and [99mTc]HMPAO-single photon emission computed tomography (SPECT) in 2 patients.. After the amobarbital injection into the left frontal opercular region, there was no recognizable language dysfunction in 3 patients. In these 3 patients, the lesions in or adjacent to the frontal operculum were completely resected without postoperative language impairment. In the remaining 2 patients, temporary language impairment after the amobarbital injection into the left frontoopercular and Wernicke's region, respectively, suggested language functions in these areas. Surgery was restricted to the left mesiotemporal lobe in 1 patient. In the other patient, the tumor infiltrating the frontal operculum was restrictively resected. Postoperatively, the first patient had no language impairment, but the latter had transient global aphasia, from which she recovered.. Selective temporary amobarbital inactivation of brain regions that may be associated with language has clearly indicated the presence or absence of language functions in these regions. The test contributed substantially to planning of the surgical approach in each patient. The predictive value of the amobarbital test was demonstrated by the postoperative outcome.

Topics: Adolescent; Adult; Amobarbital; Cerebral Angiography; Epilepsy; Epilepsy, Frontal Lobe; Epilepsy, Temporal Lobe; Female; Frontal Lobe; Functional Laterality; Humans; Injections, Intra-Arterial; Language; Magnetic Resonance Imaging; Male; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon; Treatment Outcome

To assess the clinical utility of high-resolution inter-ictal single photon emission tomography (SPET) of regional cerebral perfusion and high-resolution magnetic resonance imaging (MRI) of the brain with a phased-array temporal lobe coil, 35 patients with presumed partial epilepsy were evaluated prospectively by these techniques in addition to prolonged video/electroencephalographic (EEG) monitoring. Twenty of these patients had surgical treatment of partial epilepsy with outcome determinations spanning from 12 months to 3 years at follow-up. There were four categories of imaging findings as compared to scalp/sphenoidal EEG localization. Category I included 12 patients (34% of total) in whom there was complete imaging and EEG concordance. Category II included 4 patients (11%) in whom MRI and EEG were concordant but SPET was divergent or normal. Category III included 13 patients (37%) in whom SPET and EEG were concordant but MRI was divergent or normal. Category IV included 4 patients (11%) in whom neither SPET nor MRI was concordant with EEG. In this study, the relative sensitivities of SPET and MRI for localization of partial epilepsy based on prolonged scalp/sphenoidal video/EEG recordings were 76% and 49%, respectively. We conclude that these neuroimaging techniques (phased-array MRI and inter-ictal cerebral perfusion SPET) are complementary and useful in the pre-operative evaluation of patients with partial epilepsy.

Topics: Adolescent; Adult; Aged; Cysteine; Electroencephalography; Epilepsies, Partial; Epilepsy, Complex Partial; Epilepsy, Temporal Lobe; Female; Follow-Up Studies; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Organotechnetium Compounds; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Temporal Lobe; Time Factors; Tomography, Emission-Computed; Treatment Outcome; Videotape Recording

Peri-ictal SPECT provides unique information on the dynamic changes in regional cerebral blood flow (rCBF) that occur during seizure evolution and, thus, could be useful in clarifying the poorly understood interplay of the interictal and ictal states in human focal epilepsy. The regional hyperperfusion observed on ictal SPECT is generally believed to be a consequence of electrical seizure activity. However, recent studies using invasive long-term cortical CBF monitoring have demonstrated that rCBF changes occur up to 20 min prior to ictal electroencephalography (EEG) onset. Because of apparent technical difficulties, no preictal SPECT studies have been reported so far. Therefore, we present our results on two patients with temporal lobe epilepsy in whom preictal SPECT scans were performed fortuitously under continuous video-EEG monitoring control.. Technetium-99m-hexamethyl propyleneamine oxime was injected 11 min (Patient 1) and 12 min (Patient 2) before clinical and EEG seizure onset, as documented from simultaneous video-EEG monitoring in two patients with temporal lobe epilepsy. We obtained accurate anatomical reference of CBF changes visible on SPECT by a special coregistration technique of MRI and SPECT.. Whereas interictal SPECT showed a hypoperfusion of the temporal lobe ipsilateral to the seizure focus, on preictal SPECT, a significant increase in rCBF in the epileptic temporal lobe could be observed. These rCBF changes were not accompanied by any significant changes of the ongoing EEG.. Our study provides evidence that rCBF is increased in the epileptic temporal lobe several minutes before EEG seizure onset. Thus, rCBF changes observed on peri-ictal SPECT scan cannot be considered a mere consequence of EEG seizure activity but may rather reflect a change in neuronal activity precipitating the transition from the interictal to the ictal state.

Topics: Adult; Brain; Cerebrovascular Circulation; Electroencephalography; Epilepsy, Temporal Lobe; Female; Humans; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

To determine the frequency and patterns of periictal cerebellar hyperperfusion, whether it is associated with increased cerebellar atrophy, and whether cerebellar hyperperfusion and cerebellar atrophy are associated with predisposing clinical factors or with the outcome of epilepsy surgery.. Periictal and interictal SPECT scans and volumetric brain magnetic resonance imaging (MRI) were quantitatively analyzed in 54 consecutive patients with medically refractory partial epilepsy. Their histories were reviewed and their postsurgical outcomes assessed.. Significant periictal cerebellar hyperperfusion was found in 26 (48.1%) patients, of whom 18 had CCH, two had homolateral cerebellar hyperperfusion (HCH), and six had symmetrical bilateral hyperperfusion (BCH). No relation found between the site of the SPECT seizure localization and the presence or type of cerebellar hyperperfusion. CCH was more common when the injected seizure involved unilateral clonic motor activity (p < 0.05). A smaller MRI relative cerebellar volume (cerebellar volume/cerebral volume) was correlated with a greater seizure frequency (Rs = -0.30; p < 0.05) but not with the duration of epilepsy. There was no difference in the cerebellar volumes between the different patterns of cerebellar perfusion (p > 0.05). However, patients without a focal structural MRI lesion had significantly smaller cerebellar volumes (p < 0.05). In patients who underwent epilepsy surgery (n = 31), there was a trend for those without excellent outcomes to have smaller relative cerebellar volumes than did those with excellent outcome (10.6 vs. 11.8%; p = 0.08).. Periictal changes in cerebellar perfusion, particularly CCH, are common in patients with intractable partial epilepsy. However, periictal hyperperfusion does not appear to be a major contributor to the development of cerebellar atrophy.

Topics: Adolescent; Adult; Aged; Atrophy; Cerebellar Diseases; Cerebellum; Child; Child, Preschool; Epilepsies, Partial; Epilepsy, Temporal Lobe; Female; Humans; Infant; Magnetic Resonance Imaging; Male; Middle Aged; Regional Blood Flow; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Treatment Outcome

We report a patient with bilateral independent temporal lobe seizures in whom two [99mTc]HMPAO single photon emission computed tomograph (SPECT) scans were performed during two different seizures. In the first periictal SPECT, [99mTc]HMPAO was injected in the interval between two closely spaced seizures (one localized in the left temporal lobe and the other in the right temporal lobe). SPECT images showed hypoperfusion in the left lateral temporal lobe, hyperperfusion of the left mesial temporal region, and pronounced hyperperfusion in the right anterior temporal lobe. These results suggest both a postictal left temporal SPECT pattern and an ictal right temporal pattern. In the second periictal SPECT, [99mTc]HMPAO was injected immediately after a right temporal lobe seizure and showed right lateral temporal lobe hypoperfusion and right mesial hyperperfusion, suggesting a postictal right temporal SPECT pattern. Interpretation of the periictal SPECT should take into account EEG changes at the time or in the minutes immediately after injection of [99mTc]HMPAO.

Topics: Adult; Electroencephalography; Epilepsy, Temporal Lobe; Female; Functional Laterality; Humans; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon

The association between temporal lobe epilepsy and schizophrenia suggests that the critical abnormality may be pathology within the temporal lobes. People with schizophrenia-like psychosis of epilepsy (SLPE) provide a useful group in which to examine the importance of temporal and frontal lobe dysfunction in schizophrenia.. A verbal fluency activation paradigm and a 99mTc HMPAO SPET were used to study frontotemporal function in people with SLPE (n = 12), schizophrenia (n = 11) and epilepsy (n = 16).. People with SLPE differed from both other groups by showing lower blood flow in the left superior temporal gyrus during performance of a verbal fluency task compared with a word repetition task (F = 5.4, P = 0.01). During the verbal fluency task people with primary schizophrenia showed a greater increase in blood flow in anterior cingulate (F = 4.5, P = 0.02) than the other two groups. There were no between-group differences in frontal brain regions.. Our findings support an association between left temporal lobe abnormality and SLPE. The different patterns of activation observed in people with primary schizophrenia and SLPE suggests that different pathophysiological mechanisms may operate in these two groups. In SLPE the pathophysiology may be relatively confined to the dominant temporal lobe.

Topics: Adult; Epilepsy, Temporal Lobe; Female; Humans; Male; Radiopharmaceuticals; Schizophrenia; Schizophrenic Psychology; Speech Disorders; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

To understand the pathological basis of focal hypoperfusion seen on interictal 99Tc(m) hexamethylpropyleneamine oxime (HMPAO) single-photon-emission computed tomography (SPECT) in intractable temporal lobe epilepsy, and to determine why the technique may be misleading in the localization and lateralization of the seizure focus in some cases.. Interictal 99Tc(m) HMPAO SPECT and proton magnetic resonance spectroscopy (1H MRS) of the mesial temporal regions were performed in 14 children with intractable temporal lobe epilepsy not caused by a foreign tissue lesion.. Hypoperfusion of one temporal lobe ipsilateral to the seizure focus was demonstrated in 10 (71%) of the children; 1H MRS correctly lateralised in eight of these 10. No asymmetry of perfusion of the anterior temporal regions was seen in the remaining four children; on 1H MRS, three of these were bilaterally abnormal but nonlateralising. Repeated SPECT and 1H MRS in three children demonstrated changes over time, the findings from the two techniques being consistent with each other on both the initial and the repeated scans.. Abnormalities demonstrated by 1H MRS correlate well with those seen on interictal SPECT and can help to understand the pathologic basis of these SPECT abnormalities. Furthermore, the presence of bilateral damage can result in an absence of perfusion asymmetry on interictal SPECT.

Topics: Adolescent; Aspartic Acid; Cerebrovascular Circulation; Child; Child, Preschool; Choline; Creatine; Electroencephalography; Epilepsy, Temporal Lobe; Female; Functional Laterality; Humans; Magnetic Resonance Spectroscopy; Male; Organotechnetium Compounds; Oximes; Phosphocreatine; Protons; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon

A 49-year-old man was admitted to our hospital because of epileptic seizures and memory dysfunction. He had been experiencing seizures several times a day since the age of 43 years. Despite antiepileptic drug therapy (sodium valproate [VPA] and clonazepam [CZP], he suffered from frequent complex partial seizures originating in the temporal lobe, and he had a memory disturbance since age 47. When carbamazepine (CBZ) was substituted for VPA and CZP, the epileptic seizures stopped and the memory disturbance improved. Noninvasive regional cerebral blood flow (rCBF) measurements using 99mTc-HMPAO-SPECT imaging were performed twice. The initial measurements on admission showed overall decreased rCBP that was more prominent in the cerebral cortex than in the subcortical nuclei. A follow-up SPECT examination after clinical improvement revealed a marked overall increase in rCBF, especially in the cerebral cortex. The SPECT findings suggest that the memory disturbance in this patient may have been associated with the overall cerebral blood hypoperfusion. This overall hypoperfusion can be attributed to the frequent complex partial seizures and/or the adverse effect of VPA and CZP. SPECT can provide important information suggesting the pathogenesis of memory disturbance associated with epilepsy.

Topics: Anticonvulsants; Brain; Cerebrovascular Circulation; Electroencephalography; Epilepsy, Temporal Lobe; Humans; Magnetic Resonance Imaging; Male; Memory Disorders; Middle Aged; Neuropsychological Tests; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Topics: Amnesia; Brain; Cerebral Cortex; Cerebrovascular Circulation; Epilepsy, Complex Partial; Epilepsy, Temporal Lobe; Follow-Up Studies; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon

To assess patterns of postictal cerebral blood flow in the mesial temporal lobe by coregistration of postictal 99mTc-HMPAO SPECT with MRI in patients with confirmed mesial temporal lobe epilepsy.. Ten postictal and interictal 99mTc-HMPAO SPECT scans were coregistered with MRI in 10 patients with confirmed mesial temporal lobe epilepsy. Volumetric tracings of the hippocampus and amygdala from the MRI were superimposed on the postictal and interictal SPECT. Asymmetries in hippocampal and amygdala SPECT signal were then calculated using the equation: % Asymmetry =100 x (right - left) / (right + left)/2.. In the postictal studies, quantitative measurements of amygdala SPECT intensities were greatest on the side of seizure onset in all cases, with an average % asymmetry of 11.1, range 5.2-21.9. Hippocampal intensities were greatest on the side of seizure onset in six studies, with an average % asymmetry of 9.6, range 4.7-12.0. In four scans the hippocampal intensities were less on the side of seizure onset, with an average % asymmetry of 10.2, range 5.7-15.5. There was no localising quantitative pattern in interictal studies.. Postictal SPECT shows distinctive perfusion patterns when coregistered with MRI, which assist in lateralisation of temporal lobe seizures. Hyperperfusion in the region of the amygdala is more consistently lateralising than hyperperfusion in the region of the hippocampus in postictal studies.

Topics: Amygdala; Cerebrovascular Circulation; Electroencephalography; Epilepsy, Temporal Lobe; Hippocampus; Humans; Magnetic Resonance Imaging; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

The role of single photon emission computed tomography (SPECT) as an independent confirmation test in presurgical evaluation of medically intractable temporal lobe epilepsy has not been critically investigated. Because spreading ictal discharges may cause a concomitant increase of cerebral blood flow in remote cerebral regions, a careful analysis of peri-injection EEG patterns and their relation to ictal SPECT may be important in evaluating the reliability of ictal SPECT. Both interictal and ictal EEG and SPECT were reviewed in 19 patients with temporal lobe epilepsy who achieved a successful seizure outcome after surgery. Patients were divided into unitemporal and bitemporal groups according to the lateralization of interictal epileptiform discharges (IED). Ictal EEG features were classified into lateralized and nonlateralized groups. The concordance between SPECT and EEG lateralizations was examined in each patient and correlated to the documented epileptogenic temporal lobe. Interictal SPECT correctly lateralized in eight of nine patients with unitemporal IED and in five of 10 patients with bitemporal IED. Ictal SPECT was highly concordant with the peri-injection ictal EEG but correctly lateralized the epileptogenic region in only 11 of 19 patients. When both pre- and postinjection EEG epochs lateralized ipsilaterally, all ictal SPECT images showed concordant lateralization. If pre- and postinjection EEG epochs were either different in lateralization or nonlateralization, ictal SPECT images often showed complex patterns of cerebral perfusion with a high incidence of false lateralization. Interictal SPECT was more sensitive and reliable in patients with unitemporal IED than in patients with bitemporal IEDs. Ictal SPECT was closely related with peri-injection EEG epochs but with frequent false lateralization. The role of ictal SPECT as an independent confirmation test in presurgical evaluation should be reappraised.

Topics: Adolescent; Adult; Cysteine; Electroencephalography; Epilepsy, Temporal Lobe; Female; Functional Laterality; Humans; Male; Organotechnetium Compounds; Radiopharmaceuticals; Retrospective Studies; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon

We sought to determine whether patterns of ictal hyperfusion demonstrated using [99mTC]HMPAO (hexamethylpropylene amine oxime) single photon emission computed tomography (SPECT) predict outcome of temporal lobectomy; in particular, whether the more extensive patterns of ictal hyperperfusion are associated with poor outcome. We studied 63 patients who had ictal SPECT studies prior to temporal lobectomy. Hyperperfusion on ictal SPECT scans was lateralized, and classified into: (i) 'typical', (ii) 'typical with posterior extension', (iii) 'bilateral' and (iv) 'atypical' patterns. Outcome (minimum of 2 years follow-up) was classified as either seizure free, or not seizure free. Actuarial analysis was used to test the relationship of SPECT patterns with outcome. There were 35 cases with the typical ictal SPECT pattern, 13 posterior, nine bilateral and six atypical cases. The atypical pattern was associated with lack of pathology in the surgical specimen. Outcome was similar for the typical, posterior and bilateral with 60%, 69% and 67% seizure free, respectively. In contrast, the atypical group had a worse outcome with only 33% seizure free. Actuarial analysis showed a significant difference in outcome between patients with the typical pattern, and patients with the atypical pattern (P = 0.04). We conclude that extended patterns of ictal perfusion in temporal lobe epilepsy do not predict poor outcome, indicating that extended hyperperfusion probably represents seizure propagation pathways rather than intrinsically epileptogenic tissue. Atypical patterns of hyperperfusion are associated with poor outcome and may indicate diffuse or extra-temporal epileptogenicity.

Topics: Actuarial Analysis; Adolescent; Adult; Cerebrovascular Circulation; Epilepsy, Temporal Lobe; Female; Follow-Up Studies; Humans; Male; Middle Aged; Observer Variation; Retrospective Studies; Sclerosis; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon; Treatment Outcome

Ictal single photon emission computed tomography (SPECT) has been evaluated as an adjunctive localizing technique in temporal lobe epilepsies and, to a lesser degree, in some extratemporal epilepsies. The purpose of this study was to determine whether occipital lobe seizures are associated with distinctive ictal cerebral blood perfusion (rCP) patterns.. SPECT was used with the tracer 99mTc HMPAO to image ictal rCP in 6 patients in whom clinical, EEG, and imaging data indicated occipital lobe seizures.. Two patterns of rCP were seen. Four patients had hyperperfusion that was restricted to the occipital lobe, and two patients had hyperperfusion of the occipital lobe and the ipsilateral mesial temporal lobe, with hypoperfusion of the lateral temporal lobe. The latter 2 patients had clinical and surface EEG evidence of temporal lobe involvement in the seizure discharge.. Ictal rCP patterns in occipital lobe seizures are distinct from those in temporal lobe seizures and may vary according to whether or not ipsilateral temporal lobe structures are involved in the ictal discharge.

Topics: Adolescent; Adult; Child; Diagnosis, Differential; Electroencephalography; Epilepsy; Epilepsy, Temporal Lobe; Functional Laterality; Humans; Magnetic Resonance Imaging; Occipital Lobe; Regional Blood Flow; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon

Previous studies of interictal regional cerebral blood flow (rCBF) in temporal lobe epilepsy have shown variable correlations with clinical measures. We used high spatial resolution hexamethyl propyleneamine oxime single photon emission computed tomography (HMPAO SPECT) in 80 consecutive patients with complex partial seizures (CPS), comparing results with those from a large series of normal subjects. Visual image analysis detected abnormalities of rCBF in 41 of 80 (51%; numeric analysis detected abnormalities in 38 of 80). Age at epilepsy onset was significantly younger in patients with temporal hypoperfusion (p = 0.002), and the frequency distribution of hypoperfusion versus age at epilepsy onset was reverse exponential. The results of numerical image analysis showed that degree of hypoperfusion did not vary with age at epilepsy onset. These data suggest a single insult operating early in life as a cause of temporal hypoperfusion, as has been shown for mesial temporal sclerosis (MTS). We could not demonstrate relationships with other clinical variables, including time since last seizure.

Topics: Adolescent; Adult; Age of Onset; Cerebrovascular Circulation; Child; Diagnosis, Differential; Electroencephalography; Epilepsy, Complex Partial; Epilepsy, Temporal Lobe; Female; Humans; Male; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon

We studied cerebral perfusion patterns in the various subtypes of TLE, as determined by pathology and good outcome after temporal lobectomy (as confirmation of temporal origin).. We studied clinical features and ictal technetium 99m hexamethyl-propyleneamineoxime (99mTc-HM-PAO) single-photon emission-computed tomography (SPECT) in four subgroups of patients with intractable temporal lobe epilepsy (TLE) treated with surgery: hippocampal sclerosis (group 1, n = 10), foreign-tissue lesion in mesial temporal lobe (group 2, n = 8), foreign-tissue lesion in lateral temporal lobe (group 3, n = 7), and normal temporal lobe tissue with good surgical outcome (group 4, n = 5).. No major clinical differences in auras, complex partial seizures or postictal states were identified among the groups. Ictal SPECT showed distinct patterns of cerebral perfusion in these subtypes of TLE. In groups 1 and 2, hyperperfusion was seen in the ipsilateral mesial and lateral temporal regions. In group 3, hyperperfusion was seen bilaterally in the temporal lobes with predominant changes in the region of the lesion. Hyperperfusion was restricted to the ipsilateral anteromesial temporal region in group 4. Ipsilateral temporal hyperperfusion in mesial onset seizures can be explained by known anatomic projections between mesial structures and ipsilateral temporal neocortex. Bilateral temporal hyperperfusion in lateral onset seizures can be explained by the presence of anterior commissural connections between lateral temporal neocortex and the contralateral amygdala.. We conclude that the perfusion patterns seen on ictal SPECT are helpful for subclassification of temporal lobe seizures, whereas clinical features are relatively unhelpful. These perfusion patterns provide an insight into preferential pathways of seizure propagation in the subtypes of TLE.

Topics: Adolescent; Adult; Child; Epilepsy, Temporal Lobe; Female; Functional Laterality; Humans; Middle Aged; Organotechnetium Compounds; Oximes; Regional Blood Flow; Retrospective Studies; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon; Treatment Outcome

The usefulness of noninvasive regional cerebral blood flow measurements using Tc-99m hexamethylpropylene amine oxime (HMPAO) was evaluated in 45 patients with interictal temporal lobe epilepsy. Seizure frequency did not show any influence on flow values or side-to-side asymmetry. Patients taking phenytoin had a significantly lower mean cerebral blood flow (mean 9.5%) and lower mean cerebellar blood flow (mean 12.9%) than those not taking it. Moreover, phenytoin reduced regional cerebral blood flow in the temporal regions more prominently on the contralateral side of the epileptic focus than on the ipsilateral side. Positive MRI findings of hippocampal sclerosis along with visually detected temporal hypoperfusion on SPECT showed a lower regional cerebral blood flow and greater flow asymmetry than other imaging findings in the temporal region. Results suggest that noninvasive cerebral blood flow measurements using Tc-99m HMPAO may give useful information about interictal cerebral blood flow around an epileptic focus and about the effects of antiepileptic drugs on brain function in temporal lobe epilepsy.

Topics: Adolescent; Adult; Aged; Anticonvulsants; Brain; Cerebellum; Cerebrovascular Circulation; Epilepsy, Temporal Lobe; Female; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Organotechnetium Compounds; Oximes; Phenytoin; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Image processing techniques were applied to SPECT brain images to aid in the localization of epileptic foci.. Ictal and interictal cerebral perfusion SPECT images were acquired from 12 epilepsy patients (6 temporal, 6 extratemporal) after injection of 20 mCi 99mTc-HMPAO. Each ictal scan was registered to the same patient's interictal scan. Normalization of the three-dimensional data was applied to account for global percent brain uptake and total injected activity. After registration, normalization and subtraction of the SPECT images and functional difference images were computed. Difference images were calculated, which give a quantitative measure of perfusion alterations during ictus. The resulting difference images were also registered with each patient's MRI scan which permits localization of perfusion changes onto anatomical structures.. Areas in the brain where significant perfusion increases occur correlate with areas confirmed to be seizure foci. Four of the six patients with known temporal lobe seizure foci exhibited significant perfusion increases on the difference images. These areas demonstrate a percent increase of perfusion larger than 40%. For the extratemporal seizure patients, four of the four confirmed seizure sites were diagnosed with difference images. Results on the remaining two patients were inconclusive.. When compared to side-by-side visual interpretation of the ictal and interictal SPECT images, registration of SPECT and MR images together with calculated difference maps greatly enhances the ability to localize epileptic seizure foci. This offers the potential to locate epileptic seizure foci using a noninvasive, inexpensive imaging procedure and data processing algorithm.

Topics: Adolescent; Adult; Algorithms; Brain; Cerebrovascular Circulation; Child; Epilepsies, Partial; Epilepsy, Temporal Lobe; Female; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Organotechnetium Compounds; Oximes; Subtraction Technique; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

We retrospectively compared ictal technetium 99m hexamethylpropyleneamineoxime single-photon emission computed tomography (SPECT) and interictal 18F-fluorodeoxyglucose positron emission tomography (PET) in 35 patients with well-lateralized temporal lobe epilepsy (TLE). Based on SPECT scans the two observers correctly lateralized seizure foci with certainty in 89% of patients; interobserver agreement was excellent. Both observers incorrectly lateralized the seizure focus on two SPECT scans; one error was explained by rapid electroencephalographic spread to the contralateral side and for the other patient, isotope was injected during a brief aura. Based on PET scans, observers correctly lateralized the foci with certainty in 63% and with lesser confidence in 83%; four incorrect lateralizations were made by one observer and none by the other. PET interobserver disagreement was explained by differences between observers in weighting the relative hypometabolism in medial and lateral temporal regions. The detection rate for PET was lower in the absence of structural imaging abnormalities (60 vs 87%). PET yielded correct lateralizations in the 2 patients for whom SPECT interpretation was difficult. We conclude that both ictal SPECT and interictal PET are sensitive methods for the lateralization of TLE, but SPECT can be interpreted with greater certainty and is more sensitive when magnetic resonance imaging findings are negative. False lateralization is rare with ictal SPECT and can be explained when interpreted in conjunction with electroclinical data. Both investigations have complementary roles when localization is difficult.

Topics: Adolescent; Adult; Cerebrovascular Circulation; Deoxyglucose; Epilepsy, Temporal Lobe; Female; Fluorodeoxyglucose F18; Glucose; Hippocampus; Humans; Male; Middle Aged; Observer Variation; Organotechnetium Compounds; Oximes; Retrospective Studies; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed; Tomography, Emission-Computed, Single-Photon

Interictal rCBF-SPECT is frequently being used as an adjunctive method for localization of an epileptogenic area during presurgical evaluation of patients suffering from medically refractory temporal lobe epilepsy. This study retrospectively evaluates interictal rCBF-SPECT using Tc-99m-HMPAO in comparison to the results of MRI. The final results of surface EEG and ECoG and the postsurgical clinical results as to seizure frequency were used a a 'gold-standard' for the evaluation of both imaging procedures. As spatial resolution is discussed to be the major reason for higher sensitivity of F-18-DG-PET compared to rCBF-SPECT, special attention has been paid to the spatial resolution of the different SPECT systems being used in this study. In 55 patients the complete data set could be obtained retrospectively, 36 of them being evaluated using SPECT systems with relatively low spatial resolution (Picker Dyna 2000, Elscint Helix) and 19 pt. being evaluated using moderate- to high-resolution SPECT systems (ADAC Genesys, DSI Ceraspect). Overall sensitivity of the interictal rCBF-SPECT was 75%, with 69% for low-resolution systems and 84% for high-resolution systems. Approximately at the same time when our institution installed the ADAC Genesys, the MRI equipment was changed form the 1.5 T Philips Gyroscan S15 to the 1.5 T Philips Gyroscan ACS II, the latter allowing superior imaging opportunities. Overall sensitivity of MRI was 60%, with 56%, for the Gyroscan S15 and 68% for the Gyroscan ACS II. The overall positive predictive value (PPV) was 87% for the interictal rCBF-SPECT and 87% for the MRI. Due to the lack of true negative studies in this population specificity was not calculated. False lateralization using rCBF-SPECT occurred in 5 pts. (9%), however, in 3 pts. the area of hypoperfusion correlated with a detectable MRI pathology, yet EEG/ECoG revealed the epileptogenic focus to be elsewhere. In conclusion, the interictal rCBF-SPECT revealed reasonable sensitivity and PPV in pt. suffering from focal temporal lobe epilepsy and modern SPECT systems showed significantly improved results. Since there is a variety of possible reasons for regional cortical hypoperfusion, the interictal SPECT could add significant information prior to the application of ECoG. This specially appeared to be useful in patients with abnormal MRI scan. Furthermore, in patients presenting with a clear pathology on MRI and a corresponding EEG focus, ECoG could be avoided if the interictal

Topics: Adolescent; Adult; Cerebrovascular Circulation; Epilepsy, Temporal Lobe; Female; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Organotechnetium Compounds; Oximes; Retrospective Studies; Sensitivity and Specificity; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Single-photon emission tomography (SPET) using radioligands that are fixed on first pass through the cerebral circulation shows distinctive and rapidly changing blood flow patterns accompanying temporal lobe seizures. We sought to determine the optimal time to perform SPET studies for clinical seizure lateralization in temporal lobe epilepsy. Interictal, ictal and postictal SPET scans of 73 consecutively studied patients with unilateral temporal lobe epilepsy were read by three blinded observers to assess the accuracy of lateralization in each condition. The blinded observers correctly identified the side of focus in 97% of ictal studies, 72% of postictal studies and 50% of interictal studies. No incorrect scores were made in the ictal studies, whilst 5% of postictal and 12% of interictal studies were lateralized to the wrong side. Inter-observer agreement was best with the ictal studies. The dramatic perfusion changes of ictal SPET provide consistent, reliable and easily interpretable information that is superior to that provided by interictal and postictal studies. Injection of ligand during seizures is therefore the method of choice for SPET to aid the non-invasive lateralization of temporal seizure foci.

Topics: Adult; Cerebrovascular Circulation; Epilepsy, Temporal Lobe; Female; Humans; Male; Observer Variation; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Temporal Lobe; Time Factors; Tomography, Emission-Computed, Single-Photon

Ictal increase in regional cerebral blood flow as judged by single-photon emission tomography (SPET) is a common phenomenon during focal epileptic seizures. Up to 2 min postictally, regional hyperperfusion is a consistent finding with technetium-99m hexamethylpropylene amine oxime (HMPAO) in temporal lobe epilepsy. A new 99mTc-labelled lipophilic cerebral blood flow imaging agent, bicisate, has considerably longer radiochemical stability and yields better image quality than 99mTc-HMPAO. In this report, we present the case of a 21-year-old female patient with temporal lobe complex partial seizures. Magnetic resonance imaging revealed right hippocampal sclerosis. A dose of 550 MBq of 99mTc-bicisate was injected 35 s after the onset of a seizure during intracranial EEG-videotelemetry. At the moment of injection, subdural EEG demonstrated the beginning of late ictal discharges and postictal suppression in the right temporomesial areas. Late ictal SPET images showed marked right fronto-temporo-parietal hypoactivity. The interictal SPET study clearly showed right frontotemporal hypoactivity. These preliminary data suggest that 99mTc-bicisate shows late ictal/early postictal hypoactivity which might represent the primary change in neuronal metabolism rather than the secondary change in cerebral blood flow.

Topics: Adult; Brain; Cerebrovascular Circulation; Cysteine; Electroencephalography; Epilepsy, Temporal Lobe; Female; Humans; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Time Factors; Tomography, Emission-Computed, Single-Photon

Single photon emission computed tomography (SPECT) used in conjunction with HM-PAO (Ceretec-Amersham International) was used to image regional cerebral blood flow (rCBF) in 28 patients with medically intractable complex partial seizures during or soon after a seizure, and interictally. Changes from interictal rCBF were seen in 26/28 (93%) patients. The main findings were; 1) During the seizure--hyperperfusion of the whole temporal lobe; 2) Up to 2m postically--hyperperfusion of the hippocampus with hypoperfusion of lateral temporal structures; 3) From 2-15m postically--hypoperfusion of the whole temporal lobe. When compared with EEG and MRI data, correct localisation to one temporal lobe was obtained in 23 patients. In one further patient bilateral temporal foci, and in a further two patients frontal foci, were correctly identified. There were no disagreements between EEG and SPECT localisation. Temporal lobe surgery was successful (by the criterion of at least 90% reduction in seizure frequency) in all but one of the 23 patients operated on. It is concluded that ictal/postictal SPECT is a reliable technique for the presurgical localisation of complex partial seizures. The data indicate a likely sequence of changes in rCBF during and after complex partial seizures of temporal lobe origin.

Topics: Adolescent; Adult; Brain Mapping; Cerebrovascular Circulation; Child; Child, Preschool; Dominance, Cerebral; Electroencephalography; Epilepsy, Temporal Lobe; Evoked Potentials; Female; Hippocampus; Humans; Male; Organotechnetium Compounds; Oximes; Psychosurgery; Regional Blood Flow; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon

Ictal SPECT provides unique information for the clinician treating patients with refractory epilepsy and reveals insights into the pathophysiology of seizures. We describe our methods for the routine attainment of ictal images using 99mTc-HMPAO. We have devised and implemented techniques for rapid reconstitution of 99mTc-HMPAO adjacent to the video-EEG monitoring suite such that the tracer can be rapidly injected into patients when spontaneous seizures occur. Our quality assurance data show that this can be done safely outside a nuclear medicine department. The clinical results in patients with temporal lobe epilepsy show that ictal injections (97% correct lateralization of focus, 0% incorrect) are more sensitive and accurate compared to interictal studies (48% correct, 10% incorrect), demonstrating that the implementation of these techniques is worthwhile.

Topics: Brain; Electroencephalography; Epilepsy, Temporal Lobe; Hospital Departments; Humans; Image Processing, Computer-Assisted; Organotechnetium Compounds; Oximes; Quality Assurance, Health Care; Sensitivity and Specificity; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Fourteen patients with temporal lobe epilepsy, 9 patients after amygdalohippocampectomy and 3 healthy volunteers were examined with the new benzodiazepine receptor marker 123I-Iomazenil and SPECT. For comparison perfusion SPECT studies with 99mTc-HMPAO were done and a quantitative ROI analysis of the data performed. This quantitative analysis consisted of calculation of right-to-left ratios for 123I-Iomazenil SPECTs, whereby values of 1 were obtained with narrow standard deviations. ROI measurements of the medial occipital, frontal and parietal cortex, the cerebellum and white matter showed a pattern of benzodiazepine receptor concentration in concordance with that previously found in PET and autoradiographic studies, if 123I-Iomazenil ROIs were normalized to the corresponding 99mTc-HMPAO ROIs. The abnormal distribution in the temporal lobes will not be discussed in this paper.

Topics: Adult; Aged; Amygdala; Epilepsy, Temporal Lobe; Female; Flumazenil; Hippocampus; Humans; Iodine Radioisotopes; Male; Middle Aged; Organotechnetium Compounds; Oximes; Receptors, GABA-A; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Topics: Cerebellum; Cerebrovascular Disorders; Electroencephalography; Epilepsy, Temporal Lobe; Female; Humans; Middle Aged; Organotechnetium Compounds; Oximes; Radionuclide Imaging; Regional Blood Flow; Technetium Tc 99m Exametazime

The ictal increase of regional cerebral blood flow has yet to be fully utilised in the investigation of focal seizures. Although single photon emission tomography (SPECT) is being increasingly used in the localisation of epileptic foci, the evolution and time courses of the peri-ictal perfusion changes have yet to be clarified. We performed serial SPECT studies in the interictal, ictal and immediate postictal states in 12 patients with refractory temporal lobe epilepsy to define the patterns and duration of peri-ictal cerebral blood flow changes. Visual analysis showed a constant pattern of unilateral global increases in temporal lobe perfusion during seizures which suddenly switched to a pattern of relative mesial temporal (hippocampal) hyperperfusion and lateral temporal hypoperfusion in the immediate postictal period. Quantitative analysis confirmed the visual assessment. Lateral temporal cortex ictal/normal side to side ratios were increased by mean 35.1% (95% confidence interval 21.8% to 48.4%) more in the ictal studies than in the interictal studies and mesial temporal cortex ratios increased by mean 30.8% (22.4% to 39.2%). In the postictal state, however, lateral temporal ratios were reduced by mean 7.7% (-15.8% to 0.4%) compared with interictal values, whereas mesial temporal perfusion was maintained compared with the interictal studies. These observations provide critical information for interpreting scans which can be used in the localisation of epileptic foci. This postictal switch in blood flow patterns may reflect the underlying metabolic processes of neuronal activation and recovery and have implications for understanding the neurobiology of human epileptic seizures.

Topics: Basal Ganglia; Brain; Brain Ischemia; Cerebral Cortex; Dominance, Cerebral; Electroencephalography; Epilepsy, Temporal Lobe; Evoked Potentials; Hippocampus; Humans; Monitoring, Physiologic; Organotechnetium Compounds; Oximes; Regional Blood Flow; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

We performed 99mTc-hexamethylpropyleneamineoxime-single-photon emission computed tomography (SPECT) and 18F-fluorodeoxyglucose-positron emission tomography (PET) in 20 epileptic patients with well-lateralized temporal electroencephalographic focus, normal computed tomographic scan, and brain magnetic resonance imaging (MRI) either normal (n = 10) or showing nonspecific changes in the epileptogenic temporal lobe (n = 10). In patients with a normal MRI, PET exhibited focal hypometabolism in 80%, whereas SPECT showed corresponding hypoperfusion in only 20%. In patients with an abnormal MRI, PET and SPECT yielded 100% and 90% sensitivity, respectively. The metabolic and regional cerebral blood flow disturbances were topographically concordant with electroencephalographic and MRI findings in all these patients. Only patients with a large and pronounced hypometabolism on PET images exhibited hypoperfusion on SPECT. Spatial resolution appeared to be the critical factor responsible for the higher sensitivity of PET. However, this superiority of PET did not prove clinically useful in patients whose SPECT was abnormal, particularly when brain MRI showed nonspecific changes in the epileptogenic temporal lobe.

Topics: Adolescent; Adult; Deoxyglucose; Epilepsy, Temporal Lobe; Female; Fluorine Radioisotopes; Fluorodeoxyglucose F18; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Seizures, Febrile; Technetium Tc 99m Exametazime; Tomography, Emission-Computed; Tomography, Emission-Computed, Single-Photon

It was the aim of this study to compare benzodiazepine (Bz) receptor binding and cerebral perfusion in patients with partial epilepsy. Single photon emission tomography (SPET) studies with the flow-marker technetium 99m hexamethylpropylene amine oxine (99mTc-HMPAO) and with the 123I-labelled Bz-receptor ligand Ro 16-0154 (123I-Iomazenil) were performed in 12 patients with partial epilepsy, all with normal magnetic resonance imaging (MRI) and computed tomography (CT) scans. The SPET studies with 123I-Iomazenil were carried out 5 min and 2 h after injection. At 2 h the distribution of activity was very similar to the expected distribution of Bz-receptors in the human brain, known from positron emission tomography (PET) work and post-mortem studies. Early images showed a significantly higher tracer accumulation in the area of the basal ganglia, cerebellum, and naso-pharyngeal space. This finding is caused by non-specific binding and the contribution of the tracer in the blood pool in this phase. Also after 2 h p.i. of 123I-Iomazenil, 9 of the 12 patients showed a focal decrease of of Bz-receptor binding. Ten patients had focal flow abnormalities with 99mTc-HMPAO SPET. In 8 subjects impairment of flow was seen in sites of reduced 123I-Iomazenil uptake. 123I-Iomazenil is suitable for Bz-receptor mapping. In this series of patients, Bz-receptor mapping with SPET seems to offer no advantage over 99mTc-HMPAO in the detection of epileptic foci.

Topics: Adult; Brain; Cerebrovascular Circulation; Epilepsy, Temporal Lobe; Female; Flumazenil; Humans; Iodine Radioisotopes; Male; Organotechnetium Compounds; Oximes; Receptors, GABA-A; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Interictal 99mTc-HMPAO SPECT images were compared to ictal EEG localization in 51 patients with intractable temporal lobe epilepsy to determine their usefulness for preoperative seizure focus localization. Both quantified temporal lobe asymmetry and blinded visual detection of temporal lobe hypoperfusion were employed. Visual analysis detected ipsilateral hypoperfusion in 18 (39%) of the 46 patients with a unilateral focus and contralateral hypoperfusion in 3. None of the five patients with bitemporal foci had unilateral hypoperfusion. The positive predictive value of unilateral temporal lobe hypoperfusion was 86% (18/21). Quantified anterior temporal lobe asymmetry, greater than a previously derived normal range, correctly identified the focus in 22 (48%) but gave the wrong side in 5, resulting in a predictive value of 81%. The degree of asymmetry correlated inversely with age of seizure onset, but not with other clinical parameters, histology, or verbal and nonverbal memory. The usefulness of interictal 99mTc-HMPAO SPECT for pre-operative seizure focus localization is limited by low sensitivity when performed with a conventional rotating gamma camera. This suggests that ictal or immediate postictal imaging may be necessary for this purpose.

Topics: Adult; Electroencephalography; Epilepsy, Temporal Lobe; Humans; Organotechnetium Compounds; Oximes; Preoperative Care; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Topics: Amobarbital; Brain; Cerebrovascular Circulation; Epilepsy, Temporal Lobe; Humans; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

The intracarotid amobarbital sodium, or Wada, test has been used to localize speech and memory function prior to surgical treatment of temporal lobe seizures. The authors mixed technetium-99m hexamethyl-propyleneamine oxime (HMPAO) with amobarbital sodium and injected the mixture in 25 patients with epilepsy. Single photon emission computed tomography (SPECT) of the brain was then performed to determine intracerebral distribution of the amobarbital sodium. Results of SPECT were compared with those of conventional and digital subtraction angiography (DSA). The distribution of Tc-99m HMPAO and, presumably, amobarbital sodium varied from patient to patient. SPECT revealed a statistically different distribution from that predicted with conventional angiography. The distribution also often differed from that of DSA, although the difference was not significant. SPECT revealed infrequent delivery to mesial temporal lobe structures. This emphasizes the need for caution in the use of the intracarotid amobarbital sodium test to predict the outcome of removal of these areas.

Topics: Adolescent; Adult; Amobarbital; Angiography, Digital Subtraction; Carotid Artery, Internal; Dominance, Cerebral; Epilepsy, Temporal Lobe; Female; Humans; Injections, Intra-Arterial; Male; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon

The aim of the present study was to evaluate the predictive value of interictal single-photon emission computed tomography (SPECT) using technetium-99m-labeled hexamethyl propyleneamine oxime (HMPAO) for the outcome after temporal lobectomy in patients with complex partial seizures. Out of 40 patients, 21 underwent right-sided and 19 left-sided temporal lobectomy. EEG and CT/MRI were primarily used to select the side of surgery. SPECT results correlated with temporal lobectomy in 68% of the patients. After surgical intervention, memory function was tested for both sides. Following left-sided temporal lobectomy, verbal memory was impaired in 8% of the patients, if SPECT agreed with the side selected for surgery, but in 83%, if it diverged from it. In the present study, there was no relationship between SPECT concordance with the side of temporal lobectomy and outcome as to seizure frequency and non-verbal memory. We conclude that preoperative interictal HMPAO/SPECT can contribute to the prediction of postoperative verbal memory function and that this method should be considered for use prior to temporal lobectomy.

Topics: Adolescent; Adult; Brain Neoplasms; Child; Epilepsy, Temporal Lobe; Female; Gliosis; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Prognosis; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon

We used single-photon emission computed tomography (SPECT) to study postictal cerebral blood flow (CBF) in 51 patients with temporal lobe epilepsy. There were 78 seizures studied, 77 by early postictal injection of Tc-99m HMPAO (delay from seizure onset = 4.3 +/- 4.5 min) and one by ictal injection. Increased focal temporal lobe uptake, predominantly confined to the anteromesial region, was present in 83% and declined rapidly over 5 minutes. Reduced activity in the lateral temporal lobe accompanied the mesial increase in 80% of studies, extending over much of the ipsilateral hemisphere and closely associated with the degree and extent of postictal EEG slow waves. These patterns enabled correct seizure localization by blinded analysis in 69% (31/45) of the patients with a unilateral EEG focus. The remainder showed bilateral or no changes. One of six patients with bitemporal EEG foci had unilateral perfusion changes. The positive predictive value for the correct localization of a unilateral focus by postictal SPECT was 97% (31/32). Postictal CBF imaging with SPECT can be used to support noninvasive electrographic localization and may decrease the need for invasive electrode studies.

Topics: Adult; Cerebrovascular Circulation; Electroencephalography; Epilepsy, Temporal Lobe; Humans; Organotechnetium Compounds; Oximes; Postoperative Period; Technetium Tc 99m Exametazime; Temporal Lobe; Time Factors; Tomography, Emission-Computed

Twenty-eight patients with drug resistant temporal lobe epilepsy (DRTLE) were studied using single photon emission computed tomography (SPECT) using xenon-133 inhalation and Tc99m-d, 1-HMPAO with TOMOMATIC 64 as part of a presurgical evaluation programme. The visually evaluated flow-images were studied after blinding and the results subsequently compared to the EEG, MRI and CT scanning studies. In 24 patients a significant low flow region was seen in one temporal lobe. The SPECT result corresponded to the EEG findings in all but 6 patients. In 2 of these patients no side localization was indicated by EEG, while in four patients the EEG suggested that the opposite side was epileptogenic. Ictal SPECT and MRI/CT agreed with the resting SPECT study in three patients, while one patient has remained undiagnosed with respect to side-localization. In 14 patients discordance between SPECT and the CT scan was observed, but in 11 of these patients the SPECT study correlated with the other focal diagnostic tools. In 11 of the 21 patients studied by MRI, the results corresponded to SPECT; in 7 of the 10 which did not correspond, ictal studies of EEG and SPECT defined the side, in four of these 7 patients. Using the neuroimaging tools in concert 16 patients have been selected for surgery. All patients have benefited from surgery. These preliminary results correspond favourably with earlier studies comparing SPECT and PET with CT, MR and EEG.

Topics: Adult; Blood Flow Velocity; Dominance, Cerebral; Electroencephalography; Epilepsy, Temporal Lobe; Evoked Potentials; Humans; Organotechnetium Compounds; Oximes; Regional Blood Flow; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon

Ictal single photon emission computed tomography recordings were performed in 9 patients in the course of 11 seizures. Injections of radionuclide were made an average of 72 seconds after the onset of the seizure as indicated by electroencephalography. All patients also underwent interictal recordings. In 6 patients, the localization of the electroencephalographic focus and the morphological lesions corresponded with the ictal hyperperfusion. This could be seen in single photon emission computed tomography. Seizures triggered by hyperventilation, and seizures of patients with anatomical brain lesions (e.g., cysts, surgical defects, and recent injections of technetium-hexamethylene-propylene-amine-oxime) showed an absent or noncorresponding localization of the ictal recording. The ictal and interictal recording seems suitable as a confirmatory noninvasive method for the localization of the epileptogenic focus, particularly in the preoperative evaluation of epilepsy.

Topics: Adolescent; Adult; Cerebrovascular Circulation; Child; Electroencephalography; Epilepsy, Temporal Lobe; Female; Frontal Lobe; Humans; Male; Organotechnetium Compounds; Oximes; Radionuclide Imaging; Technetium Tc 99m Exametazime

We present the results of single photon emission computed tomography (SPECT) in 40 patients with temporal lobe epilepsy and normal computed transmission tomography (CT). Abnormalities of regional cerebral blood flow were found in 26 patients. There was focal hypoperfusion alone in 14, focal hyperperfusion alone in 6, and both types of abnormality in 6. In 4 patients there were bilateral abnormalities. Repeat SPECT showed persistence of interictal hyperperfusion in 5/12 patients. There were no significant correlations between SPECT findings and clinical parameters, and no relation between the persistence of interictal hyperperfusion and time since last seizure or seizure frequency. Where SPECT and multiple surface EEG recordings were both lateralising, agreement between them was good. The results of this study support the usefulness of HMPAO SPECT in detecting lateralising abnormalities in temporal lobe epilepsy. Interictal hyperperfusion may be commoner than previous publications suggest, and may be persistent in some cases.

Topics: Adolescent; Adult; Aged; Cerebrovascular Circulation; Child; Epilepsy, Temporal Lobe; Humans; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

Eight patients with drug-resistant complex-partial seizures were subjected to left- and right-sided intracarotid sodium amytal (ISA) procedures during preoperative investigations for surgical treatment. Regional changes of cerebral and cerebellar blood flow during barbiturization were measured by [99mTc]-HMPAO-SPECT. Crossed cerebellar diaschisis (CCD) was observed in 13 out of 16 tests (81%) as well as ipsilateral cerebral hypoperfusion (87%). Thus CCD occurred more frequently in ISA procedures than in previously studied patients with cerebral infarctions and tumors. Since intracarotid injections of sodium amytal lead to hypoperfusion mainly in those areas of the brain that are supplied by the middle cerebral artery, functional suppression of these regions is supposed to be one of the main preconditions of CCD. Our findings suggest that CCD as demonstrated by the SPECT-technique is a common phenomenon in ISA procedures.

Topics: Adolescent; Adult; Amobarbital; Carotid Artery, Internal; Cerebellar Diseases; Cerebrovascular Circulation; Epilepsy, Temporal Lobe; Female; Humans; Injections, Intra-Arterial; Male; Organotechnetium Compounds; Oximes; Speech; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

Technetium (99mTc) hexamethyl propylene amine oxime (HM-PAO) was injected into the internal carotid artery in ten epileptic patients after the end of amobarbital speech-memory tests. The cerebral perfusion as visualized from SPET was compared to cerebral angiographies, which showed unilateral filling of intracranial vessels in seven patients. SPET revealed cross-flow between the hemispheres in four of these seven patients. In three patients in whom the angiograms had shown bilateral contrast filling, SPET showed cross-flow in only two. It is concluded that 99mTc-HM-PAO SPET examinations provide valuable information for correct interpretation of amobarbital tests on cognitive hemisphere functions. The SPET technique may help to explain atypical speech and memory responses caused by unusual intracranial vascularization.

Topics: Adult; Amobarbital; Brain; Carotid Artery, Internal; Cerebral Angiography; Cerebrovascular Circulation; Epilepsy, Temporal Lobe; Female; Humans; Injections, Intra-Arterial; Male; Memory Disorders; Organotechnetium Compounds; Oximes; Speech Disorders; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Topics: Encephalitis; Epilepsy, Temporal Lobe; Herpes Simplex; Humans; Male; Middle Aged; Organometallic Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

Topics: Adult; Cerebrovascular Circulation; Epilepsy, Temporal Lobe; Evaluation Studies as Topic; Humans; Male; Organometallic Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

Topics: Brain Ischemia; Cerebrovascular Circulation; Dominance, Cerebral; Epilepsies, Partial; Epilepsy; Epilepsy, Temporal Lobe; Humans; Organometallic Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

Topics: Adolescent; Adult; Electroencephalography; Epilepsies, Partial; Epilepsy, Temporal Lobe; Female; Humans; Magnetic Resonance Imaging; Male; Organometallic Compounds; Oximes; Posture; Technetium; Technetium Tc 99m Exametazime; Tomography, Emission-Computed; Tomography, X-Ray Computed; Xenon Radioisotopes