technetium-tc-99m-bicisate and Epilepsy

The localizing value of ictal single-photon emission computed tomography (SPECT) performed with cerebral blood flow agents in patients with epilepsy is based on cerebral metabolic and perfusion coupling. Ictal hyperperfusion is used to localize the epileptogenic zone noninvasively, and is particularly useful in magnetic resonance (MR)-negative partial epilepsy and focal cortical dysplasias. Subtraction ictal SPECT coregistered with MRI (SISCOM) improves the localization of the area of hyperperfusion. Ictal SPECT should always be interpreted in the context of a full presurgical evaluation. Early ictal SPECT injections minimize the problem of seizure propagation and of nonlocalization due to an early switch from ictal hyperperfusion to postictal hypoperfusion during brief extratemporal seizures. The degree of thresholding of SISCOM images affects the sensitivity and specificity of ictal SPECT. Ictal hypoperfusion may reflect ictal inhibition or deactivation. Postictal and interictal SPECT studies are less useful to localize the ictal-onset zone. Statistical parametric mapping analysis of groups of selected ictal-interictal difference images has the potential to demonstrate the evolution of cortical, subcortical, and cerebellar perfusion changes during a particular seizure type, to study seizure-gating mechanisms, and to provide new insights into the pathophysiology of seizures.

Topics: Brain; Brain Mapping; Cerebral Cortex; Cysteine; Electroencephalography; Epilepsy; Humans; Magnetic Resonance Imaging; Organotechnetium Compounds; Preoperative Care; Regional Blood Flow; Sensitivity and Specificity; Subtraction Technique; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

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

Single Photon Emission Computerized Tomography (SPECT) is a valuable tool in the assessment of epileptic patients. Radiotracers that distribute according to regional cerebral blood flow permit the identification of altered perfusion to an epileptogenic zone both ictally and interictally. This technique has proven especially useful in temporal lobe epilepsy.

Topics: Adolescent; Brain; Child; Child, Preschool; Cysteine; Epilepsy; Humans; Image Interpretation, Computer-Assisted; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Functional brain imaging plays an important role in seizure focus localisation. However, truly ictal single-photon emission tomography (SPET) studies are not routinely performed owing to technical problems associated with the use of tracers and methodological and logistical difficulties. In this study we tried to resolve both of these issues by means of a new procedure: technetium-99m ethyl cysteinate dimer (ECD) brain SPET performed during seizures pharmacologically provoked with pentylenetetrazol, a well-known central and respiratory stimulant. We studied 33 drug-resistant epileptic patients. All patients underwent anamnestic evaluation, neuropsychological and psychodynamic assessment, magnetic resonance imaging, interictal and ictal video-EEG monitoring, and interictal and ictal SPET with (99m)Tc-ECD. In order to obtain truly ictal SPET, 65 mg of pentylenetetrazol was injected every 2 minutes and, immediately the seizure began, 740 MBq of (99m)Tc-ECD was injected. The scintigraphic findings were considered abnormal if a single area of hyperperfusion was present and corresponded to the site of a single area of hypoperfusion at interictal SPET: the "hypo-hyperperfusion" SPET pattern. In 27 of the 33 patients (82%), interictal-ictal SPET showed the hypo-hyperperfusion SPET pattern. Video-EEG showed a single epileptogenic zone in 21/33 patients (64%), and MRI showed anatomical lesions in 19/33 patients (57%). Twenty-two of the 27 patients with hypo-hyperperfusion SPET pattern underwent ablative or palliative surgery and were seizure-free at 3 years of follow-up. No adverse effects were noted during pharmacologically provoked seizure. It is concluded that ictal brain SPET performed during pharmacologically provoked seizure provides truly ictal images because (99m)Tc-ECD is injected immediately upon seizure onset. Using this feasible procedure it is possible to localise the focus, to avoid the limitations due to the unpredictability of seizures, to avoid pitfalls due to late injection, to avoid intracranial EEG recording and to minimise costs. The clinical value of our method is confirmed by the good outcome after 3 years of follow-up in those patients submitted to ablative or palliative surgery.

Topics: Adolescent; Adult; Cysteine; Drug Resistance; Electroencephalography; Epilepsy; Feasibility Studies; Female; Follow-Up Studies; Humans; Injections; Magnetic Resonance Angiography; Male; Organotechnetium Compounds; Pentylenetetrazole; Radiopharmaceuticals; Reference Values; Seizures; Sensitivity and Specificity; Tomography, Emission-Computed, Single-Photon; Video Recording

The aim of this study was to evaluate the use of 99mTc-ethyl cysteinate dimer (ECD), also known as 99mTc-bicisate, in the presurgical evaluation of patients suffering from medically intractable epilepsy.. Twenty-three brain SPECT studies (8 ictally and 15 interictally) were performed on 16 patients with a high-resolution annular SPECT system (CERASPECT). For the ictal studies, the tracer was injected in the very early phase of the seizure. The delay between seizure onset and 99mTc-ECD injection was 2-20 sec.. Interictally, all patients showed circumscribed hypoperfusions. In four patients, the SPECT lesion represented only structural defects. Circumscribed increased tracer uptake was observed in all ictal studies. For all patients with temporal lobe epilepsy without significant mass lesion, in whom an interictal and ictal 99mTc-ECD-SPECT study could be obtained, the asymmetry index was 0.88 +/- 0.03 for the interictal and 1.23 +/- 0.08 for the ictal studies.. The data suggest that 99mTc-ECD is an effective marker of cerebral perfusion imaging in epilepsy. In comparison to other tracers, it has a high in vitro stability and is therefore particularly useful for ictal studies in the very early phase after seizure onset.

Topics: Adolescent; Adult; Brain; Cysteine; Electroencephalography; Epilepsy; Female; Humans; Male; Organotechnetium Compounds; Seizures; Time Factors; Tomography, Emission-Computed, Single-Photon

Topics: Adolescent; Adult; Brain; Child; Child, Preschool; Cysteine; Epilepsy; Female; Fluorodeoxyglucose F18; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Positron-Emission Tomography; Radiopharmaceuticals; Tomography, Emission-Computed, Single-Photon

To evaluate the localization of functional deficit area in epileptogenic zones of the brain in seven refractory and seven non-refractory epilepsy dogs using technetium 99m labeled with ethyl cysteinate dimer and interictal single photon emission computed tomography [

Topics: Animals; Brain; Cysteine; Cystine; Dog Diseases; Dogs; Drug Resistant Epilepsy; Epilepsy; Female; Magnetic Resonance Imaging; Male; Organotechnetium Compounds; Tomography, Emission-Computed, Single-Photon

Localization of epileptogenic focus in drug-refractory epilepsy using Tc-99m ethylene cystine dimer (ECD) brain single photon emission computed tomography (SPECT) is less studied in patients with discordant findings on video electroencephalogram (VEEG) and MRI. The study was done to evaluate brain SPECT for epileptogenic focus localization and postoperative seizure freedom.. Epilepsy patients with discordant VEEG and MRI findings underwent brain SPECT at ictal and interictal phases. Various groups unilateral/bilateral mesial temporal sclerosis (MTS), solitary and multifocal lesional, nonlesional epilepsy were studied for localization of epileptogenic focus and postoperative seizure freedom (>2 years) using Engels classification. Reasons for nonoperability was evaluated in nonoperated group.. SPECT could localize epileptogenic focus in 49/67 (73.13%) and guided surgery in 19/33 (57.57%) patients in operated group. SPECT was useful in 12 (46.12%) of unilateral (2)/bilateral (10) MTS. Postoperative seizure freedom of Engels Class I and II in 22 (66.67%), III in six (18.2%) and IV in one patient based on SPECT findings (P = 0.0086). Overall sensitivity and specificity were 79.3% and 85.7%, respectively. SPECT could localize epileptogenic focus in 23/34 (67.64%) patients in nonoperated group; 10 (29.41%) patients refused for surgery and no epileptogenic focus was localized in the rest of 14 (41.2%).. Ictal SPECT showed incremental value and was found necessary for epileptogenic focus localization and subsequent surgery in unilateral/bilateral MTS in this study. Seizure freedom in patients undergoing epilepsy surgery based on ictal SPECT assistance was comparable to the surgical group not requiring ictal SPECT.

Topics: Adolescent; Adult; Child; Clinical Decision-Making; Cysteine; Electroencephalography; Epilepsy; Female; Humans; Magnetic Resonance Imaging; Male; Organotechnetium Compounds; Postoperative Period; Retrospective Studies; Seizures; Tomography, Emission-Computed, Single-Photon; Young Adult

We developed a prototype CdTe SPECT system with 4-pixel matched collimator for brain study. This system provides high-energy-resolution (6.6%), high-sensitivity (220 cps/MBq/head), and high-spatial-resolution images. The aim of this study was to evaluate dual-isotope study of CBF and central benzodiazepine receptor (BZR) images using Tc-ECD and I-IMZ with the new SPECT system in patients with epilepsy comparing with single-isotope study using the conventional scintillation gamma camera.. This study included 13 patients with partial epilepsy. The BZR images were acquired at 3 hours after I-IMZ injection for 20 minutes. The images of IMZ were acquired with a conventional 3-head scintillation gamma camera. After BZR image acquisition with the conventional camera, Tc-ECD was injected, and CBF and BZR images were acquired simultaneously 5 minutes after ECD injection with the new SPECT system. The CBF images were also acquired with the conventional camera on separate days. The findings were visually analyzed, and 3D-SSP maximum Z scores of lesions were compared between the 2 studies.. There were 47 abnormal lesions on BZR images and 60 abnormal lesions on CBF images in the single-isotope study with the conventional camera. Dual-isotope study with the new system showed concordant abnormal findings of 46 of 47 lesions on BZR and 54 of 60 lesions on CBF images with the single-isotope study with the conventional camera. There was high agreement between the 2 studies in both BZR and CBF findings (Cohen κ values = 0.96 for BZR and 0.78 for CBF). In semiquantitative analysis, maximum Z scores of dual-isotope study with the new system strongly correlated with those of single-isotope study with the conventional camera (BZR: r = 0.82, P < 0.05, CBF: r = 0.87, P < 0.05).. Our new SPECT system permits dual-isotope study for pixel-by-pixel analysis of CBF and BZR information with the same pathophysiological condition in patients with epilepsy.

Topics: Adult; Brain; Cysteine; Epilepsy; Female; Gamma Cameras; Humans; Iodine Radioisotopes; Male; Organotechnetium Compounds; Semiconductors; Tomography, Emission-Computed, Single-Photon

BACKGROUND The aim of this study was to explore the value of NeuroGam software in diagnosis of epilepsy by 99Tcm-ethyl cysteinate dimer (ECD) brain imaging. MATERIAL AND METHODS NeuroGam was used to analyze 52 cases of clinically proven epilepsy by 99Tcm-ECD brain imaging. The results were compared with EEG and MRI, and the positive rates and localization to epileptic foci were analyzed. RESULTS NeuroGam analysis showed that 42 of 52 epilepsy cases were abnormal. 99Tcm-ECD brain imaging revealed a positive rate of 80.8% (42/52), with 36 out of 42 patients (85.7%) clearly showing an abnormal area. Both were higher than that of brain perfusion SPECT, with a consistency of 64.5% (34/52) using these 2 methods. Decreased regional cerebral blood flow (rCBF) was observed in frontal (18), temporal (20), and parietal lobes (2). Decreased rCBF was seen in frontal and temporal lobes in 4 out of 36 patients, and in temporal and parietal lobes of 2 out of 36 patients. NeuroGam further showed that the abnormal area was located in a different functional area of the brain. EEG abnormalities were detected in 29 out of 52 patients (55.8%) with 16 cases (55.2%) clearly showing an abnormal area. MRI abnormalities were detected in 17 out of 43 cases (39.5%), including 9 cases (52.9%) clearly showing an abnormal area. The consistency of NeuroGam software analysis, and EEG and MRI were 48.1% (25/52) and 34.9% (15/43), respectively. CONCLUSIONS NeuroGam software analysis offers a higher sensitivity in detecting epilepsy than EEG or MRI. It is a powerful tool in 99Tcm-ECD brain imaging.

Topics: Adolescent; Adult; Brain; Cysteine; Electroencephalography; Epilepsy; Female; Humans; Image Interpretation, Computer-Assisted; Magnetic Resonance Angiography; Male; Middle Aged; Neuroimaging; Organotechnetium Compounds; Software; Tomography, Emission-Computed, Single-Photon; Young Adult

Subtraction ictal single photon emission computed tomography (SPECT) co-registered to magnetic resonance imaging (MRI) (SISCOM) is a useful modality to identify epileptogenic focus. Using this technique, several studies have generally considered the area of highest ictal hyperperfusion, as outlined by thresholding the difference images with a standard z score of 2, to be highly concordant to the epileptogenic focus. In clinical practice, several factors influence ictal hyperperfusion and using different SISCOM thresholds can be helpful. We aimed to systematically evaluate the localizing value of various z scores (1, 1.5, 2, and 2.5) in a seizure-free cohort following resective epilepsy surgery, and to examine the localizing information of perfusion patterns observed at each z score.. Twenty-six patients were identified as having ictal-interictal SPECT images, preoperative and postoperative MRI studies, and having remained seizure free for at least 6 months after temporal or extratemporal surgical resection. SISCOM analysis was performed using preoperative MRI studies, and then blindly reviewed for localization of hyperperfused regions. With the added information from postoperative, coregistered MRI, perfusion patterns were determined.. Using pair-wise comparisons, we found that the optimal z score for SPECT-SISCOM localization of the epileptogenic zone was 1.5, not the commonly used z score of 2. The z score of 1.5 was 84.8% sensitive and 93.8% specific. The z score of 1.5 had a moderate interrater agreement (0.70). When an hourglass configuration hyperperfusion pattern was present, a trend toward correctly localizing the seizure onset region was suggested (100% of the 11 observed occurrences). Nonetheless this trend was not statistically significant, possibly reflecting the small number of occurrences in our study.. SISCOM is a useful modality in evaluating patients for epilepsy surgery. This study shows that the z score of 1.5 represents a highly sensitive and specific SISCOM threshold that should be examined in conjunction with the traditionally used z score of 2 to enhance the chances of correct localization. Further prospective investigations are needed to confirm this finding in large patient series.

Topics: Adolescent; Adult; Aged; Algorithms; Brain Mapping; Child; Child, Preschool; Cysteine; Electroencephalography; Electronic Data Processing; Epilepsy; Female; Fluorodeoxyglucose F18; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Organotechnetium Compounds; Retrospective Studies; Sensitivity and Specificity; Tomography, Emission-Computed, Single-Photon; Young Adult

Topics: Brain; Cysteine; Epilepsy; Female; Fluorodeoxyglucose F18; Humans; Organotechnetium Compounds; Positron-Emission Tomography; Recurrence; Tomography, Emission-Computed, Single-Photon

We performed brain perfusion single-photon emission computed tomography (SPECT) to detect the abnormal brain region in children with both autism spectrum disorders (ASD) and medically intractable epilepsy.. Fifteen children aged 4-16 years underwent multimodal examinations (MRI, interictal and/or ictal ECD-SPECT, EEG and MEG) to investigate their indications for surgical treatment. All children were diagnosed with ASD according to DSM-IV criteria and intractable epilepsy. Despite medical treatment for more than a year, all experienced at least one seizure per month. All had no underlying basic disorders. Each SPECT result was statistically analyzed by comparing with standard SPECT images obtained from our institute (easy Z-score imaging system; eZIS). The relationship between the eZIS pattern and EEG abnormalities or clinical symptoms was investigated.. All children showed focal abnormal patterns on eZIS and focal spikes on EEG. In all children, eZIS revealed a mixed hypoperfusion pattern, especially in the prefrontal cortex, medial frontal cortex, anterior cingulate cortex, medial parietal cortex, and/or anterior temporal cortex. In seven of 12 children who underwent interictal SPECT studies, areas of hypoperfusion were related to the focus observed on EEG; in six children, the focal EEG spikes represented areas of hyperperfusion. The children were divided into two groups according to the main type of hypoperfusion patterns seen on eZIS; medial-cingulate type and temporal type. No significant relationship was observed between the areas of hypoperfusion and clinical symptoms. eZIS showed the epileptic focus clearly on ictal SPECT.. SPECT was useful to detect the abnormal brain region not only in searching for the epileptic focus but also in assessing the low or high functioning region of the brain.

Topics: Adolescent; Brain; Brain Mapping; Child; Child Development Disorders, Pervasive; Child, Preschool; Cysteine; Electroencephalography; Epilepsy; Female; Humans; Magnetic Resonance Imaging; Male; Organotechnetium Compounds; Radiopharmaceuticals; Tomography, Emission-Computed, Single-Photon

This study was designed to evaluate the utility of subtraction ictal SPECT coregistered to MRI (SISCOM) in atypical psychogenic nonepileptic seizures (PNES). Video-EEG monitoring (vEEG) is the gold standard for PNES diagnosis but, like any modality, has limitations. In difficult cases in which the diagnosis is suspected but remains in question after vEEG, a complementary study that could help differentiate epilepsy from PNES would be desirable. Thirteen SISCOM studies performed in patients with a final diagnosis of PNES were retrospectively reviewed. Common indications for SISCOM were semiology consistent with partial epilepsy (9/13), abnormal head MRI (5/13), and reported abnormal routine EEG (5/13). SISCOM was negative in 85% (11/13) of patients and was helpful in increasing the diagnostic certainty of PNES in these exceptional cases.

Topics: Adolescent; Adult; Aged; Brain Mapping; Cysteine; Electroencephalography; Epilepsy; Female; Functional Laterality; Humans; Male; Middle Aged; Organotechnetium Compounds; Personality Inventory; Psychophysiologic Disorders; Retrospective Studies; Risk Factors; Tomography, Emission-Computed, Single-Photon; Video Recording; Young Adult

To describe the ictal technetium-99 m-ECD SPECT findings in polymicrogyria syndromes (PMG) during epileptic seizures.. We investigated 17 patients with PMG syndromes during presurgical workup, which included long-term video-electroencephalographic (EEG) monitoring, neurological and psychiatry assessments, invasive EEG, and the subtraction of ictal-interictal SPECT coregistered to magnetic resonance imaging (MRI) (SISCOM).. The analysis of the PMG cortex, using SISCOM, revealed intense hyperperfusion in the polymicrogyric lesion during epileptic seizures in all patients. Interestingly, other localizing investigations showed heterogeneous findings. Twelve patients underwent epilepsy surgery, three achieved seizure-freedom, five have worthwhile improvement, and four patients remained unchanged.. Our study strongly suggests the involvement of PMG in seizure generation or early propagation. Both conventional ictal single-photon emission computed tomography (SPECT) and SISCOM appeared as the single contributive exam to suggest the localization of the epileptogenic zone. Despite the limited number of resective epilepsy surgery in our study (n = 9), we found a strong prognostic role of SISCOM in predicting surgical outcome. This result may be of great value on surgical decision-making of whether or not the whole or part of the PMG lesion should be surgically resected.

Topics: Adolescent; Brain; Child; Cysteine; Epilepsy; Female; Humans; Magnetic Resonance Imaging; Male; Malformations of Cortical Development; Organotechnetium Compounds; Radiopharmaceuticals; Subtraction Technique; Syndrome; 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

Subtraction of interictal from ictal single-photon emission computed tomography (SPECT) yields numerous foci that encompass a range of pixel values scattered in the brain. This preliminary study evaluated the significance of this range of values.. Subtraction images were obtained by registering, normalizing, and subtracting interictal from ictal SPECT for 13 patients. Pixel values of the resulting foci were divided into two groups: group I with 75-100% and group II with 50-75% of the maximal pixel value. Locations of these foci were determined, and concordance with surgical outcomes and scalp and invasive EEG findings was evaluated.. In 10 of 13 cases, group I foci showed good concordance with ictal scalp EEG. In addition, group I foci corresponded well to invasive EEG findings in nine of 10 cases. Group I foci had bilateral distributions in seven of 13 cases. In 10 of 13 cases, group I foci corresponded well to regions of surgical resection. Of these 10 patients, nine showed good concordance with scalp EEG, eight showed good invasive EEG concordance, and eight were seizure free after resection. Conversely, group II foci had good concordance with ictal scalp EEG in only five of 13 cases, and invasive EEG findings, in only five of 10 cases. Group II foci had bilateral distributions in 10 of 13 cases. All 10 cases underwent unilateral surgical resections, and all had good surgical outcomes. In six of 13 cases, group II foci showed concordance with surgical sites. Of these six foci, four had poor concordance with scalp EEG, one had poor concordance with invasive EEG, and five had good surgical outcomes. Sensitivity and specificity for seizure localization of Group I foci were 40% and 88% respectively while sensitivity and specificity of Group II foci were 20% and 79% respectively.. Our data demonstrate that foci with 75-100% of maximal pixel values show good concordance with seizure foci, whereas foci of 50-75% may not. Therefore stratifying ictal/interictal differences may improve the specificity and localizing value of subtraction SPECT.

Topics: Adolescent; Adult; Brain; Brain Mapping; Child; Child, Preschool; Cysteine; Electroencephalography; Epilepsy; Female; Functional Laterality; Humans; Infant; Magnetic Resonance Imaging; Male; Middle Aged; Organotechnetium Compounds; Retrospective Studies; Subtraction Technique; Tomography, Emission-Computed, Single-Photon; Treatment Outcome

The occurrence of epileptiform abnormalities on the EEG in patients with multiple sclerosis (MS) is rare. The following case correlates the clinical, EEG, MRI, and single photon emission computed tomographic (SPECT) findings in a patient with a long history of MS and acute onset of focal motor seizures and confusion. Two routine EEGs, brain MRI, and brain SPECT were performed. The patient was a 44-year-old woman with a long history of clinically definite MS of the relapsing-remitting and secondary progressive form with three events of focal motor seizures followed by generalized tonic-clonic seizures and postictal confusion. The first EEG done during admission showed periodic lateralized epileptiform discharges in the right temporal region. Brain MRI done several weeks later showed scattered T2 hyperintensities in several locations, including the periventricular and subcortical white matter bilaterally. Brain SPECT using Tc99-Neurolite demonstrated decreased perfusion on the right parietal and temporal lobes. This case suggests that focal motor seizures and a transient state of altered consciousness can be the result of an exacerbation of MS. The neurophysiologic expression of these clinical manifestations may present as periodic lateralized epileptiform discharges on the EEG and decreased regional perfusion on brain SPECT.

Topics: Adult; Brain; Brain Mapping; Cerebrovascular Circulation; Cysteine; Electroencephalography; Epilepsy; Female; Functional Laterality; Humans; Magnetic Resonance Imaging; Multiple Sclerosis; Organotechnetium Compounds; Radiopharmaceuticals; Tomography, Emission-Computed, Single-Photon

Basal ganglia or thalamic activation has been reported in ictal SPECT studies of patients with intractable epilepsy. We hypothesized that lateralization of activation of these subcortical structures may aid in the lateralization of seizure foci in patients in whom the cortical focus is subtle or equivocal.. This was a retrospective analysis of 72 ictal (99m)Tc-ethylcysteinate dimer SPECT studies in 43 patients with intractable epilepsy in whom seizure laterality could be eventually determined. All patients underwent video-electroencephalography (EEG) monitoring, MRI, and one or more ictal SPECT scans as well as an interictal SPECT scan. Intracranial electrode EEG monitoring and surgery were performed as clinically indicated. Ictal and interictal studies were coregistered with patients' MRI scans using automated software, and ictal minus interictal subtraction images were obtained. The presence of asymmetric basal ganglia or thalamic activation was determined by 2 experienced observers who were unaware of clinical information. The final seizure focus was determined by surgical cure in 37 patients. In patients in whom surgery was not indicated or initial surgery was performed at another institution (n = 6), a consistent focus detected by intracranial electrode monitoring or repeated stereotypical seizures all originating from the same site on video-surface EEG monitoring was considered to indicate the final seizure focus.. Thirty-five patients had neocortical seizures and 8 had mesial temporal lobe seizures. Asymmetric basal ganglia activation was seen in 22 (30.6%) studies. This activation was ipsilateral to the final determined seizure focus in 17 of 22 of these studies (77.3%) and contralateral in 5 of 22 (21.7%). Asymmetric thalamic activation was seen in 15 studies (20.8%), of which 12 of 15 (80%) were ipsilateral to the final seizure focus, whereas 3 of 15 (20%) were contralateral. In 3 of 5 studies with contralateral basal ganglia activation and 1 of 3 studies with contralateral thalamic activation, the SPECT study as a whole was found to be falsely localizing. In another 2 cases of contralateral subcortical activation, the SPECT study as a whole was considered nonlocalizing. Worse outcome was not observed in patients with false ictal SPECT subcortical lateralization; however, the presence of asymmetric subcortical uptake, regardless of relationship to seizure focus, was associated with decreased incidence of seizures at 1 y after surgery.. Although asymmetric basal ganglia or thalamic activation is common, it is rarely the sole indicator of seizure localization. However, it may be a useful confirmatory sign in subtle cases of cortical localization. In cases of false ictal SPECT subcortical lateralization, the basal ganglia appear to follow cortical activation pattern. Furthermore, there appears to be a correlation between lateralizing uptake in subcortical structures on ictal SPECT and postsurgical outcome in intractable epilepsy patients.

Topics: Adult; Basal Ganglia; Brain Mapping; Child; Cysteine; Epilepsy; Female; Follow-Up Studies; Humans; Male; Middle Aged; Organotechnetium Compounds; Predictive Value of Tests; Radiopharmaceuticals; Retrospective Studies; Single-Blind Method; Statistics as Topic; Thalamus; Tissue Distribution; Tomography, Emission-Computed, Single-Photon; Treatment Outcome

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

Serial-ictal single-photon-emission computed tomography (SPECT) examinations are presented in two infants (ages 1 and 2 years), with early ictal and ictal in one, and ictal and late ictal images in the other. Both had pharmacoresistant occipital epilepsy, due to focal cortical dysplasia. In the first case, size of ictal hyperperfusion increased in the course of the seizure from early ictal to ictal state. A concomitant ictal hypoperfusion was observed around the hyperperfused area. In the second patient, there was a dramatic difference between ictal and late ictal images. In the late ictal state, the previous occipital ictal hyperperfusion and extraoccipital ictal hypoperfusion disappeared, together with homolateral posterotemporal and contralateral occipital hyperperfusion, corresponding to seizure propagation. Ictal extratemporal blood-flow changes are therefore highly dynamic, particularly in very young children.

Topics: Age Factors; Cerebral Cortex; Child, Preschool; Cysteine; Electroencephalography; Epilepsy; Female; Humans; Infant; Occipital Lobe; Organotechnetium Compounds; Regional Blood Flow; Tomography, Emission-Computed, Single-Photon

Crossed cerebellar hyperperfusion (CCH) in epilepsy is a rare condition that is observed on ictal cerebral perfusion SPECT. The mechanism of CCH assumes that hyperperfusion in the epileptic foci of the unilateral supratentorium causes hyperperfusion secondary to the corticopontocerebellar pathway (CPCP)-mediated remote effect in the contralateral cerebellar hemisphere. This phenomenon is similar to that of crossed cerebellar diaschisis (CCD). In this report we demonstrated interictal CCH in a patient with epilepsy in technetium-99m-ethyl cysteinate dimer (Tc-99m ECD) SPECT of the brain. To the best of our knowledge, interictal CCH has not been reported in the literature. This is the first report to describe the phenomenon with interictal Tc-99m ECD SPECT.

Topics: Aged; Cerebellum; Cerebrovascular Circulation; Cysteine; Epilepsy; Humans; Magnetic Resonance Imaging; Male; Organotechnetium Compounds; Radiopharmaceuticals; Tomography, Emission-Computed, Single-Photon

A method developed for registration of ictal and interictal single-photon emission tomography (SPET), magnetic resonance imaging (MRI) and electroencephalography (EEG) is described. For SPET studies, technetium-99m ethyl cysteinate dimer (ECD) was injected intravenously while the patient was monitored on video-EEG to document the ictal or interictal state. Imaging was performed using a triple-head gamma camera equipped with a transmission imaging device using a gadolinium-153 source. The images (128x128 pixels, voxel size 3.7x3.7x3.6 mm3) were reconstructed using an iterative algorithm and postfiltered with a Wiener filter. The gold-plated silver electrodes on the patient's scalp were utilized as markers for registration of the ictal and interictal SPET images, as these metallic markers were clearly seen on the transmission images. Fitting of the marker sets was based on a non-iterative least squares method. The interictal SPET image was subtracted from the ictal image after scaling. The T1-weighted MPRAGE MR images with voxel size of 1.0x1.0x1.0 mm3 were obtained with a 1.5-T scanner. For registration of MR and subtraction SPET images, the external marker set of the ictal SPET study was fitted to the surface of the head segmented from MR images. The SPET registration was tested with a phantom experiment. Registration of ictal and interictal SPET in five patient studies resulted in a 2-mm RMS residual of the marker sets. The estimated RMS error of registration in the final result combining locations of the electrodes, subtraction SPET and MR images was 3-5 mm. In conclusion, transmission imaging can be utilized for an accurate and easily implemented registration procedure for ictal and interictal SPET, MRI and EEG.

Topics: Adolescent; Adult; Brain; Cysteine; Electroencephalography; Epilepsy; Female; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Male; Organotechnetium Compounds; Phantoms, Imaging; Radiopharmaceuticals; Tomography, Emission-Computed, Single-Photon

Topics: Brain; Cysteine; Epilepsy; Humans; Organotechnetium Compounds; Radiopharmaceuticals; Self Administration; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Ictal brain SPECT (IS) findings in neocortical epilepsy (patients without mesiotemporal sclerosis) can be subtle. This study is aimed at assessing how the seizure focus identification was improved by the inclusion of individual IS and interictal brain SPECT (ITS)-MRI image registration as well as performing IS - ITS image subtraction.. The study involved the posthoc analysis of 64 IS scans using 99mTc-ethyl cysteinate dimer that were obtained in 38 patients without mesiotemporal sclerosis but with or without other abnormalities on MRI. Radiotracer injection occurred during video-electroencephalographic (EEG) monitoring. Patients were injected 2-80 s (median time, 13 s) after clinical or EEG seizure onset. All patients had sufficient follow-up to correlate findings with the SPECT results. All patients had ITS and MRI, including a coronal volume sequence used for registration. Image registration (IS and ITS to MRI) was performed using automated software. After normalization, IS - ITS subtraction was performed. The IS, ITS, and subtraction studies were read by 2 experienced observers who were unaware of the clinical data and who assessed the presence and localization of an identifiable seizure focus before and after image registration and subtraction. Correlation was made with video-EEG (surface and invasive) and clinical and surgical follow-up.. Probable or definite foci were identified in 38 (59%) studies in 33 (87%) patients. In 52% of the studies, the image registration aided localization, and in 58% the subtraction images contributed additional information. In 9%, the subtraction images confused the interpretation. In follow-up after surgery, intracranial EEG or video-EEG monitoring (or both) has confirmed close or reasonable localization in 28 (74%) patients. In 6 (16%) patients, SPECT indicated false seizure localization.. Image registration and image subtraction improve the localization of neocortical seizure foci using IS, but close correlation with the original images is required. False localizations occur in a minority of patients.

Topics: Adult; Brain; Cysteine; Electroencephalography; Epilepsy; Female; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Male; Neocortex; Organotechnetium Compounds; Radiopharmaceuticals; Retrospective Studies; Sensitivity and Specificity; Subtraction Technique; 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

The Medical College of Georgia Hospital and Clinics (MCG) was one of the first centers in the United States (US) to institute a video electroencephalography (EEG) epilepsy monitoring unit and epilepsy surgery program. In order to surgically remove the area in the brain giving rise to seizures, the epileptogenic zone must be identified and localized. One of the newer methods used to identify the epileptogenic seizure focus is the ictal Single Photon Emission Computed Tomography (SPECT) scan, which MCG began performing in 1993. The nurses staffing the six bed Epilepsy Monitoring Unit (EMU) are trained by the Nuclear Radiology Department and Radiation Safety Officer to bandle the radioisotope during mixing, calibration and injection. The bedside nursing protocol developed assures patient and staff radiation safety and efficacious injection. Over 300 patients have been injected by nurses with a high degree of safety to patients and staff. This has resulted in positive scans that aid diagnosis. The success of the ictal SPECT protocol can be attributed to the active collaboration of our multidisciplinary team.

Topics: Cysteine; Epilepsy; Humans; Infusions, Intravenous; Monitoring, Physiologic; Organotechnetium Compounds; Patient Care Team; Safety; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Although cerebral blood flow in infants differs from that in older individuals, the distribution of 99mTc-ethyl cysteinate dimer (ECD) in infants has not been well studied. This study compared 99mTc-ECD distribution in infants and children with that in young adults.. 99mTc-ECD SPECT was performed on 37 patients suspected of having epilepsy, ranging in age from 3 mo to 26 y. The patients were divided into two age-matched groups, a drug-free group (n = 19) and a drug-taking group (n = 18), according to their anticonvulsant medication status at the time of examination. 99mTc-ECD (100-740 MBq) was injected interictally, and SPECT data were acquired using a triple-head gamma camera. Mean whole-brain counts were obtained from 10 sequential SPECT images. Regions of interest were set bilaterally on five areas of the cerebral cortex and on the basal ganglia, thalamus and cerebellum. The brain perfusion index (BPI) was obtained as a ratio of the mean counts in each region of interest to the mean whole-brain counts. The relationship between BPI and age in each region in the drug-free and drug-taking groups was analyzed separately and together using linear regression. The relationship between five patient age groups (<1 y, n = 4; 1-4 y, n = 9; 5-9 y, n = 8; 10-15 y, n = 7; >15 y, n = 9) and BPI in each region was also examined using multiple comparison analyses.. Significant positive correlations between BPI and age in the frontal cortex and cerebellum were confirmed in the drug-free group. Anticonvulsant drugs did not affect the regression lines of BPI in the frontal cortex and cerebellum. Significant differences in BPI between age groups were seen in the parietal cortex, frontal cortex, occipital cortex, basal ganglia, thalamus and cerebellum in all patients.. Age-related changes in cerebral 99mTc-ECD distribution were confirmed and found to be unaffected by the administration of anticonvulsant drugs. 99mTc-ECD uptake in children and infants is different from cerebral blood flow glucose metabolism as previously reported, especially in the cerebellum.

Topics: Adolescent; Adult; Aging; Anticonvulsants; Brain; Case-Control Studies; Cerebrovascular Circulation; Child; Child, Preschool; Cysteine; Epilepsy; Female; Gamma Cameras; Humans; Infant; Male; Organotechnetium Compounds; Radiopharmaceuticals; Tomography, Emission-Computed, Single-Photon

Because 99mTc-HMPAO and 99mTc-ECD are both used for SPECT imaging of cerebral blood flow, the question arises whether there are any differences in their respective regional cerebral distribution. For that purpose, visual and semiquantitative comparisons between 99mTc-HMPAO and 99mTc-ECD studies were performed.. Seventeen patients (4 women; 13 men; age 45-89 yr; mean age 71 yr) with various neurological diseases, except acute/subacute stroke, were investigated twice with 99mTc-HMPAO and 99mTc-ECD using a triple-headed rotating SPECT camera. After image reorientation, the two studies were evaluated visually. Seventy regions of interest (ROIs) were drawn manually and the same set of ROIs was applied in both studies. Regional indices (RI) normalized to individual brain values were calculated and first compared between two random patient groups. Second, for all patients, RI for 70 and later for 27 regions (gained after summing values of corresponding regions in different brain slices) were compared by using a paired Student's t-test applying Bonferroni's correction.. Visual evaluation demonstrated relatively high 99mTc-ECD uptake in occipital and comparatively low uptake in mediotemporal regions. Calculation of RI revealed significantly higher values in the right cerebellum, brainstem, mediotemporal regions, right basal ganglia and the thalamus in the 99mTc-HMPAO SPECT studies and higher values in the occipital, supratemporal/inferior parietal and parietal cortex in the 99mTc-ECD SPECT studies, respectively.. Significant differences in regional tracer distribution between 99mTc-HMPAO and 99mTc-ECD could be detected, probably caused by different tracer kinetics. The results indicate that direct comparisons of studies performed with 99mTc-HMPAO and 99mTc-ECD are not possible and the use of either tracer can be favorable in different clinical questions.

Topics: Aged; Aged, 80 and over; Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Cysteine; Epilepsy; Female; Humans; Male; Middle Aged; Organotechnetium Compounds; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Topics: Adult; Aged; Brain; Cerebrovascular Disorders; Child, Preschool; Cysteine; Dementia; Epilepsy; Humans; Organotechnetium Compounds; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Focal cortical dysplasia is one of the known neuronal migration disorders and has recently been recognized as a cause of intractable epilepsy. In this study, we assessed the 11C-methionine (MET) uptake in focal cortical dysplasia by PET, and then compared the results with that of 18F-fluoro-2-deoxy-D-glucose (FDG) PET and 99mTc-ethyl cysteinate dimer (ECD) SPECT.. Four patients (3 men, 1 woman; age range 16-68 yr) were examined by PET and SPECT for a presurgical examination of medically intractable seizures. In all 4 patients, 11C-MET PET was performed for 15 min, started 15 min after the administration of 511-662 MBq MET. In 3 of 4 patients, FDG PET was performed for 15 min, and started 20 min after the administration of 185-370 MBq FDG. In all 4 patients, the cerebral blood flow was also evaluated by 99mTc-ECD SPECT for 15 min after the administration of 600 MBq ECD.. In MET PET, all 4 lesions were visually recognized to have high MET uptake areas. The MET uptake of the lesions was 1.44 +/- 0.30 for the standardized uptake value (SUV) (ranging from 0.99-1.61). In FDG PET, 2 lesions were demonstrated to have low uptake areas (3.82 in SUV) while 1 had an ictal high uptake (4.74 in SUV). In ECD SPECT, 1 lesion demonstrated hypoperfusion and 1 ictal hyperperfusion while 2 showed no abnormalities. All 4 patients underwent a cortical resection and the microscopic examinations were consistent with those of focal cortical dysplasia but no evidence of a tumor was found.. MET PET is useful for identifying focal cortical dysplasia as a high uptake area.

Topics: Adolescent; Adult; Aged; Cerebral Cortex; Cerebrovascular Circulation; Cysteine; Epilepsy; Female; Fluorodeoxyglucose F18; Humans; Magnetic Resonance Imaging; Male; Methionine; Organotechnetium Compounds; Radiopharmaceuticals; Seizures; Tomography, Emission-Computed; Tomography, Emission-Computed, Single-Photon

Ictal single-photon-emission computed tomography (SPECT) provides lateralization but has technical limitations: (a) a "truly ictal" injection must be shortly after seizure onset; (b) therefore, a seizure of brief duration may be missed; (c) more than one patient may need testing at any given time; (d) a trained health professional must stay next to each patient to inject; and (e) because the radionuclide is placed in the syringe in advance of the injection, decay of the radioactive element could result in less than optimal uptake, if the same volume of material were to be used regardless of the time after ligand preparation.. We developed an automated method of ligand injection that shortens time and increases efficiency of ictal SPECT ligand injection. By using an experimental setup, we compared manual injection times with times using an automated injection system. We determined relative costs and efficiency in work hours for the manual and automated methods.. Injection times were 8-14 s with automated versus 19-26 s with manual injection. Readjusting volume for "ligand" decay was simple and accurate with the automated system. Injection times for clinical SPECT studies in three patients were 13, 13, and 12 s, respectively. The price of one pump equals 120 work hours of a nurse or 24 ictal injection attempts. Much of the nurse's time is "wasted" because no seizure occurs.. The method can be more efficient of staff, shorten injection time, and facilitate obtaining "truly ictal" injections. It allows more cost-effective use of personnel.

Topics: Algorithms; Cost-Benefit Analysis; Cysteine; Drug Delivery Systems; Epilepsy; Functional Laterality; Humans; Injections, Intravenous; Monitoring, Physiologic; Organotechnetium Compounds; Radiopharmaceuticals; Syringes; Tomography, Emission-Computed, Single-Photon

Forty-one ECD (Technetium-99m-ethyl cysteinate dimer) SPECT investigations were undertaken in the course of a presurgical diagnostic work-up in 23 patients with pharmacoresistant focal epilepsy. In 21 patients, both an ictal and interictal SPECT were conducted. In the patients receiving ictal SPECT the tracer was injected between 7 and 30 s after the seizure onset. Of the interictal SPECTs 17 of 23 showed focal hypoperfusion which was consistent in 17 cases (74%) with the area of the electrophysiological focus (EF) and 6 patients had a normal interictal SPECT. Of the ictal SPECTs 18 of 21 (86%) showed regional hyperperfusion, 18 of them in the same location as the EF. Ictal SPECT showed a hypoperfusion similar to that in interictal SPECT in another 3 patients. In these cases seizure duration was short (28-54 s), so that the tracer reached the brain postictally. Our results show that ictal ECD-SPECT is an effective method for demonstrating an epileptogenic focus. Possible reasons for false-negative ictal SPECT results are discussed.

Topics: Adolescent; Adult; Blood Flow Velocity; Brain; Brain Mapping; Cerebral Cortex; Child; Cysteine; Electroencephalography; Epilepsy; Female; Humans; Male; Middle Aged; Monitoring, Physiologic; Organotechnetium Compounds; Radiopharmaceuticals; Regional Blood Flow; Seizures; Sensitivity and Specificity; Tomography, Emission-Computed, Single-Photon

We performed 99Tcm-ethyl cysteinate dimer (ECD) interictal single photon emission tomography (SPET) in 26 children with severe therapy-resistant epilepsy. All the children underwent a detailed clinical examination, an electroencephalogram (EEG) investigation and brain magnetic resonance imaging (MRI). In 21 of the 26 children, SPET demonstrated brain blood flow abnormalities, in 13 cases in the same territories that showed EEG alterations. MRI showed structural lesions in 6 of the 26 children, while SPET imaging confirmed these abnormalities in only 5 children. The lesion not detected on SPET was shown to be 3 mm thick on MRI. Five symptomatic patients had normal SPET. In one of these patients, the EEG findings were normal and MRI revealed a small calcific nodule (4 mm thick); in the others, the EEG showed non-focal but diffuse abnormalities. These data confirm that brain SPET is sensitive in detecting and localizing hypoperfused areas that could be associated with epileptic foci in this group of patients, even when the MRI image is normal.

Topics: Adolescent; Brain; Calcinosis; Child; Child, Preschool; Cysteine; Electroencephalography; Epilepsy; Female; Humans; Infant; Magnetic Resonance Imaging; Male; Organotechnetium Compounds; Tomography, Emission-Computed, Single-Photon