technetium-tc-99m-bicisate 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

Although subtraction ictal SPECT coregistered to MRI (SISCOM) is clinically useful in epilepsy surgery evaluation, it does not determine whether the ictal-interictal subtraction difference is statistically different from the expected random variation between 2 SPECT studies. We developed a statistical parametric mapping and MRI voxel-based method of analyzing ictal-interictal SPECT difference data (statistical ictal SPECT coregistered to MRI [STATISCOM]) and compared it with SISCOM.. Two serial SPECT studies were performed in 11 healthy volunteers without epilepsy (control subjects) to measure random variation between serial studies from individuals. STATISCOM and SISCOM images from 87 consecutive patients who had ictal SPECT studies and subsequent temporal lobectomy were assessed by reviewers blinded to clinical data and outcome.. Interobserver agreement between blinded reviewers was higher for STATISCOM images than for SISCOM images (kappa = 0.81 vs kappa = 0.36). STATISCOM identified a hyperperfusion focus in 84% of patients, SISCOM in 66% (p < 0.05). STATISCOM correctly localized the temporal lobe epilepsy (TLE) subtypes (mesial vs lateral neocortical) in 68% of patients compared with 24% by SISCOM (p = 0.02); subgroup analysis of patients without lesions (as determined by MRI) showed superiority of STATISCOM (80% vs 47%; p = 0.04). Moreover, the probability of seizure-free outcome was higher when STATISCOM correctly localized the TLE subtype than when it was indeterminate (81% vs 53%; p = 0.03).. Statistical ictal SPECT coregistered to MRI (STATISCOM) was superior to subtraction ictal SPECT coregistered to MRI for seizure localization before temporal lobe epilepsy (TLE) surgery. STATISCOM localization to the correct TLE subtype was prognostically important for postsurgical seizure freedom.

Topics: Adolescent; Adult; Brain; Brain Mapping; Cysteine; Electroencephalography; Epilepsy, Temporal Lobe; Female; Functional Laterality; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Organotechnetium Compounds; Radiopharmaceuticals; Subtraction Technique; Time Factors; Tomography, Emission-Computed, Single-Photon; Treatment Outcome; 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

Déjà vu is a common experience among the normal population. However, in individuals with temporal lobe epilepsy, it often occurs as a seizure manifestation. The specific cause of such déjà vu is not yet known. Here, we report a case of epilepsy with persistent déjà vu. The patient described the state as if he were living the same life he had lived before. Blood perfusion single-photon-emission computed tomography (SPECT) performed during the persistent déjà vu showed hyperperfusion in the left medial temporal area; discontinuation of déjà vu was accompanied by disappearance of the hyperperfused area on SPECT. Analysis with three-dimensional co-registration of SPECT and MRI revealed that the hyperperfused area during the persistent déjà vu was in the entorhinal cortex of the left temporal lobe. According to recent theories of recognition memory, malfunction of the parahippocampal area may cause déjà vu. It is also suggested that epileptic activity in the parahippocampal area, especially the entorhinal cortex, may elicit déjà vu.

Topics: Anticonvulsants; Cysteine; Deja Vu; Entorhinal Cortex; Epilepsy, Temporal Lobe; Humans; Male; Memory Disorders; Middle Aged; Neuropsychological Tests; Organotechnetium Compounds; Radiopharmaceuticals; Tomography, Emission-Computed, Single-Photon

Ictal single-photon emission computed tomography (SPECT) may help localize the seizure-onset zone (SOZ) by detecting changes in regional cerebral blood flow induced by epileptic discharges. This imaging method also reveals hyperperfusions in areas of seizure propagation, including the hemisphere contralateral to the SOZ. We have studied the occurrence, the topography, and the clinical value of such contralateral ictal hyperperfusion areas (HPAs).. We examined data from presurgical evaluations of 36 consecutive patients with pharmacoresistant partial epilepsy of various localizations. Ictal and interictal SPECT examinations were made with 99mTc-ECD, and the scans were processed for coregistration, normalization, subtraction, and merging with MRI images.. Contralateral HPAs were observed in 72% of the patients: 50% of mesiotemporal epilepsy cases with hippocampal sclerosis, 85.7% of the other mesiotemporal epilepsies, 85.7% of neocortical lateral temporal epilepsies, and 87.5% of extratemporal epilepsies. Contralateral HPAs were usually symmetrical to the SOZ, forming a mirror image, observed in 57.1% of the patients. They could be slightly asymmetrical in mesiotemporal epilepsies, perhaps because of the particular anatomic pathways linking temporal lobes. In neocortical epilepsies, they were located in the cortex homotopic to the SOZ.. We show that the symmetrical nature of the mirror image usually does not disturb SPECT interpretation. It can confirm the location of the SOZ (11 patients) and even occasionally improve the precision of its definition (nine patients) by restraining several potential SOZ-related HPAs to a single one or by permitting a restricted localization of the SOZ in a large HPA.

Topics: Brain; Brain Mapping; Cysteine; Electroencephalography; Epilepsy; Epilepsy, Temporal Lobe; Follow-Up Studies; Functional Laterality; Hippocampus; Humans; Magnetic Resonance Imaging; Neural Pathways; Organotechnetium Compounds; Preoperative Care; Regional Blood Flow; Retrospective Studies; Sclerosis; Seizures; Temporal Lobe; Tomography, Emission-Computed, Single-Photon; Videotape Recording

The pathophysiological role of the extensive interictal cerebral hypometabolism in complex partial seizures (CPS) in refractory mesial temporal lobe epilepsy with hippocampal sclerosis (mTLE-HS) is poorly understood. Our aim was to study ictal-interictal SPECT perfusion versus interictal fluorodeoxyglucose (FDG)-PET metabolic patterns.. Eleven adults with refractory unilateral mTLE-HS, who were rendered seizure free after epilepsy surgery, were included. All had an interictal FDG-PET and an interictal and ictal perfusion SPECT scan. FDG-PET data were reconstructed using an anatomy-based reconstruction algorithm, which corrected for partial volume effects, and analyzed semi-quantitatively after normalization to white matter activity. Using Statistical Parametric Mapping (SPM), we compared interictal metabolism of the patient group with a control group. We correlated metabolic with ictal perfusion changes in the patient group.. Global cerebral grey matter glucose metabolism in patients was decreased 10-25% compared with control subjects. Interictal PET hypometabolism and ictal SPECT hypoperfusion were maximal in the ipsilateral frontal lobe. Ictal frontal lobe hypoperfusion was associated with crossed cerebellar diaschisis. The ipsilateral temporal lobe showed maximal ictal hyperperfusion and interictal hypometabolism, which was relatively mild compared with the degree of hypometabolism affecting the frontal lobes.. Interictal hypometabolism in mTLE-HS was greatest in the ipsilateral frontal lobe and represented a seizure-related dynamic process in view of further ictal decreases. Crossed cerebellar diaschisis suggested that there is a strong ipsilateral frontal lobe inhibition during CPS. We speculate that surround inhibition in the frontal lobe is a dynamic defense mechanism against seizure propagation, and may be responsible for functional deficits observed in mTLE.

Topics: Adult; Algorithms; Blood Glucose; Cerebellum; Cerebral Cortex; Cysteine; Dominance, Cerebral; Electroencephalography; Energy Metabolism; Epilepsy, Temporal Lobe; Evoked Potentials; Female; Fluorodeoxyglucose F18; Frontal Lobe; Hippocampus; Humans; Image Processing, Computer-Assisted; Imaging, Three-Dimensional; Male; Middle Aged; Organotechnetium Compounds; Positron-Emission Tomography; Regional Blood Flow; Sclerosis; Statistics as Topic; Temporal Lobe; 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

Dystonic posturing (DP) is one of the most reliable lateralizing symptoms for mesial temporal lobe epilepsy, although the mechanism remains unclear. We demonstrated a hyperperfusion area in the right putamen on subtracted postictal SPECT by using the automatic registration technique in one patient with ictal DP of the left hand. The putamen may play a key role in DP, similar to other diseases with dystonia.

Topics: Adult; Cysteine; Electroencephalography; Epilepsy, Temporal Lobe; Functional Laterality; Humans; Male; Organotechnetium Compounds; Putamen; Radiopharmaceuticals; Tomography, Emission-Computed, Single-Photon

To relate the occurrence of contralateral electroencephalogram slowing (CES) to amobarbital distribution, we performed electroencephalogram (EEG) monitoring and intracarotid single photon emission computed tomography (SPECT) during an intracarotid amobarbital procedure (IAP).. IAP was performed on 22 patients with temporal lobe epilepsy. CES was defined as the occurrence of significant EEG slowing on the contralateral hemisphere (>50% of the ipsilateral hemisphere slowing) after amobarbital injection. To map the distribution of the amobarbital, we injected a mixture of amobarbital and (99m)technetium-ethylcysteinate dimer (99mTc-ECD) into the internal carotid artery and performed a brain SPECT 2 h later. In the SPECT images, regions of interest were determined by ipsilateral and contralateral anterior cerebral artery territories (iACA, cACA), ipsilateral and contralateral middle cerebral artery territories (iMCA, cMCA), and ipsilateral and contralateral posterior cerebral artery territories (iPCA, cPCA), as well as ipsilateral and contralateral anterior and posterior mesial temporal regions (iAMT, cAMT, iPMT, cPMT). The perfusion of amobarbital was interpreted visually in each region.. Amobarbital was distributed in the iMCA in all the patients; in the iACA in 20 (90.9%) patients; in the iAMT in 14 (63.5%); and in the iPCA and iPMT in only two (9.1%). CES was observed in 13 (59.1%) patients. Cross-perfusion of amobarbital in limited areas of the cACA were observed in only four of 13 patients. Wada retention memory scores (WRMS) showed no significant difference between the CES- (n = 9) and CES+ (n = 13) groups.. Amobarbital rarely perfused the iPCA territory and the iPMT region and was rarely delivered to the contralateral hemisphere. The occurrence of CES was not related to the cross-perfusion of amobarbital. CES appears to be produced by a transient functional disconnection from the ipsilateral hemisphere.

Topics: Adolescent; Adult; Amobarbital; Brain; Carotid Artery, Internal; Child; Cysteine; Electroencephalography; Epilepsy, Temporal Lobe; Female; Functional Laterality; Humans; Male; Memory; Middle Aged; Organotechnetium Compounds; Radiopharmaceuticals; Regional Blood Flow; Tomography, Emission-Computed, Single-Photon

Pharmacologic activation of epileptic foci has been used experimentally with the hope that it may accelerate the presurgical evaluation of patients with medically intractable epilepsy. In this article, we will review the existing literature on these activating tests giving emphasis on the opioid analogs, and particularly alfentanil. Alfentanil is an opioid analog with rapid anesthetic effect, which has been known to trigger epileptiform discharges in epilepsy patients. 58 temporal lobe epilepsy (TLE) patients were studied with alfentanil activation during electrocorticography, at the Epilepsy Surgery Unit (ING, Brazil). An increase of the interictal epileptiform discharges was observed originating from hippocampal and parahippocampal regions (96.5%). To a lesser extent, alfentanil activated the basal and lateral temporal regions. Electrographic seizures were observed in 38%. In addition, we performed continuous video-EEG (VT/EEG) monitoring, with scalp and bilateral foramen ovale electrodes, in 12 TLE patients. The results of spontaneously observed seizures were compared with the electrographic changes following alfentanil activation (50-75 microg/kg, i.v.). In seven cases, alfentanil triggered focal electrographic seizures, ipsilaterally to the side generating the spontaneous seizures and in two patients it produced bilateral sequential activation of the temporal lobes. Ictal SPECTs during the alfentanil test showed hyperperfusion at the lateral temporal regions, ipsilaterally to the activated area or bilaterally. In summary, our study confirms the activating effect of alfentanil, and provides a strong evidence for its selective activating effect on the temporal lobes of TLE patients. The ictal SPECT during alfentanil activation did not offer any additional advantage for the localization of the ictal onset.

Topics: Adolescent; Adult; Alfentanil; Analgesics, Opioid; Cysteine; Electroencephalography; Epilepsy, Temporal Lobe; Gap Junctions; Humans; Injections, Intravenous; Organotechnetium Compounds; Radiopharmaceuticals; Retrospective Studies; Tomography, Emission-Computed, Single-Photon

The authors compared ictal SPECT injection performed by medical personnel with self-injection ictal SPECT in six patients with refractory temporal lobe epilepsy. Self-injection was safe and started faster. Self-injection subtraction ictal SPECT coregistered to MRI (SISCOM) was localizing in three patients who had a complex partial seizure, but only one of three patients who had a simple partial seizure, which may limit its usefulness in clinical practice. The localizing information of self-injection was better in three patients, and obviated the need for depth-EEG studies in one patient.

Topics: Adult; Brain Mapping; Cysteine; Epilepsy, Temporal Lobe; Female; Humans; Image Processing, Computer-Assisted; Injections, Intravenous; Magnetic Resonance Imaging; Male; Middle Aged; Organotechnetium Compounds; Radiopharmaceuticals; Self Administration; Tomography, Emission-Computed, Single-Photon

Ictal SPECT is a valuable method for the presurgical exploration of partial epilepsy. (99m)Tc Ethyl Cysteinate Dimer stable during 6h has contributed to develop ictal studies to evaluate the location of partial seizure. The aim of this study was to investigate some factors playing a possible role on the regional increase of cerebral blood flow (rCBF) Twenty-three patients with refractory partial epilepsy (temporal epilepsy n=16, extratemporal epilepsy n=7) were included. All the patients underwent a presurgical evaluation (phase I) during a week with detailed clinical history, cranial magnetic resonance imaging, monitoring EEG and video. Ictal and interictal SPECT were performed using a fast rotating brain dedicated camera (TOMOMATIC 564) in a quiet and normally illuminated room with controlled EEG (interictal) or video EEG (ictal); Scanning was started one hour after injection of ECD Tc administered in IV a few seconds after the electrical onset seizure. Slices parallel to the long axis of the temporal lobe were reconstructed. SPECT images were evaluated after normalisation. This study shows that

Topics: Adolescent; Adult; Age of Onset; Brain; Cerebrovascular Circulation; Cysteine; Electroencephalography; Epilepsies, Partial; Epilepsy, Temporal Lobe; Humans; Organotechnetium Compounds; Radiopharmaceuticals; Regional Blood Flow; Sensitivity and Specificity; Tomography, Emission-Computed, Single-Photon; Video Recording

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

This study reports quantitative measurements of the accuracy of two popular voxel-based registration algorithms--Woods' automated image registration algorithm and mutual information correlation--and compares these with conventional surface matching (SM) registration.. The registration algorithms were compared (15 different matches each) for (a) three-dimensional brain phantom images, (b) an ictal SPECT image from a patient with partial epilepsy matched to itself after modification to simulate changes in the cerebral blood flow pattern and (c) ictal/interictal SPECT images from 15 patients with partial epilepsy. Blinded visual ranking and localization of the subtraction images derived from the patient images were also performed.. Both voxel-based registration methods were more accurate than SM registration (P < 0.0005). Automated image registration algorithm was more accurate than mutual information correlation for the computer-simulated ictal/interictal images and the patient ictal/interictal studies (P < 0.05). The subtraction SPECTs from SM were poorer in visual ranking more often than the voxel-based methods (P < 0.05).. Voxel intensity-based registration algorithms provide significant improvement in ictal/interictal SPECT registration accuracy and result in a clinically detectable improvement in the subtraction SPECT images.

Topics: Algorithms; Brain; Cerebrovascular Circulation; Cysteine; Epilepsies, Partial; Epilepsy, Temporal Lobe; Humans; Image Processing, Computer-Assisted; Organotechnetium Compounds; Phantoms, Imaging; Radiopharmaceuticals; Tomography, Emission-Computed, Single-Photon

Interictal brain SPECT is useful for the localization of a seizure focus. Concomitant hypoperfusion of the ipsilateral thalamus on interictal SPECT has been noted for temporal lobe epilepsy. In this study, we aimed to evaluate the prevalence of thalamic hypoperfusion ipsilateral to temporal hypoperfusion (ipsilateral thalamic hypoperfusion) and to assess the usefulness of this finding for the lateralization of epileptic foci on interictal SPECT for temporal lobe epilepsy patients.. Forty-six patients with refractory temporal lobe epilepsy underwent interictal brain SPECT after intravenous injection of 555-740 MBq of 99mTc-ECD. Perfusion impairments in the brain, especially the temporal lobe and thalamus, were evaluated. The localization of seizure foci was determined in conjunction with scalp, ictal and cortical electroencephalography, MRI and clinical outcomes. Ictal SPECT was performed for 5 of the 12 patients.. Concomitant decreased perfusion in both the temporal lobe and the ipsilateral thalamus was observed for 12 (26%) of 46 temporal lobe epilepsy patients on interictal brain SPECT. Seven patients showed hypoperfusion in the left temporal lobe and ipsilateral thalamus. Five patients showed hypoperfusion in the right temporal lobe and ipsilateral thalamus. In addition, hypoperfusion in the ipsilateral basal ganglia (ten patients) or contralateral cerebellum (four patients) was observed.. Ipsilateral thalamic hypoperfusion is not uncommon in temporal lobe epilepsy. The exact mechanism causing ipsilateral thalamic hypoperfusion is uncertain; however, corticothalamic diaschisis may be an important factor. This finding may aid in the lateralization of seizure foci on interictal brain SPECT.

Topics: Adolescent; Adult; Cerebrovascular Circulation; Child; Cysteine; Epilepsy, Temporal Lobe; Female; Humans; Magnetic Resonance Imaging; Male; Organotechnetium Compounds; Radiopharmaceuticals; Temporal Lobe; Thalamus; Tomography, Emission-Computed, Single-Photon

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

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

Single photon emission computed tomography (SPECT) is widely used to evaluate functional abnormalities during the epileptic event. Changes in regional cerebral blood flow (rCBF) are well defined in patients with temporal lobe epilepsy (TLE) undergoing surgical resection. Nonetheless, the interpretation of ictal abnormalities in CBF beyond the temporal lobes has not been carefully addressed.. We assessed 4 patients with pathologically proven unilateral TLE who had significant ipsilateral frontal hypoperfusion in ictal studies with no other abnormalities but chronic epilepsy accounting for such findings. Patients were assessed as candidates for surgery by interictal EEG, neuropsychological studies, brain magnetic resonance imaging, scalp electrode video-EEG monitoring, and ictal SPECT.. Characteristic hyperperfusion was evident over the temporal lobe ipsilateral to the EEG focus, with significant hypoperfusion over the frontal region in 3 patients. In patient 4, frontal hypoperfusion was not statistically significant.. SPECT demonstrated relative rCBF changes beyond the epileptogenic zone in unilateral TLE. Our findings provide further insight into the pathophysiological changes underlying this condition.

Topics: Adult; Cysteine; Epilepsy, Complex Partial; Epilepsy, Temporal Lobe; Female; Functional Laterality; Humans; Magnetic Resonance Imaging; Male; Organotechnetium Compounds; Radiopharmaceuticals; Regional Blood Flow; Temporal Lobe; 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

99mTc-bicisate (ECD) was injected as a bolus into the internal carotid artery, and cerebral uptake and retention were recorded with fast-rotating single photon emission computed tomography (SPECT) equipment in four patients suffering from temporal lobe epilepsy. Quantitative regional cerebral blood flow (rCBF) was measured tomographically with the 133Xe inhalation technique. We applied a three-compartment kinetic model and algorithms modified from a previous analysis of 99mTc d,l-hexamethylpropyleneamine oxide (HM-PAO) kinetics. The bicisate brain uptake and retention curve was very similar to that of HM-PAO, and it can be described by a triexponential function including an initial steep component representing the vascular transmitted spike, a second less steep component representing back-diffusion from brain tissue to blood, and a third, very slow component, representing the very slow loss due to incomplete retention of the deesterified hydrophilic metabolites. Computerized curve-fitting on data from three patients gave average kinetic values for the first-passage (unilateral) extraction of E = 0.60 (range, 0.59-0.61); the overall retained fraction of the tracer supplied was R = 0.44 (0.43-0.45), and the conversion/clearance ratio was alpha = k3/k2 = 2.59 (2.38-2.77). This alpha is higher than that for HM-PAO, and therefore bicisate uptake as a function of blood flow is more linear than in HM-PAO. Less correction for backdiffusion is therefore needed. From 1 to 24 h there was an average loss of hydrophilic tracer of 3.5%/h, but the late distribution images were essentially unchanged over time, pointing to practically the same rate of loss in all regions.

Topics: Adolescent; Adult; Brain; Carotid Artery, Internal; Cerebrovascular Circulation; Cysteine; Epilepsy, Temporal Lobe; Female; Humans; Injections, Intra-Arterial; Male; Models, Biological; Organotechnetium Compounds; Tomography, Emission-Computed, Single-Photon