technetium-tc-99m-exametazime 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

Topics: Adult; Aged; Atrophy; Brain; Cerebral Hemorrhage; Electroencephalography; Epilepsy; Humans; Magnetic Resonance Imaging; Middle Aged; Prospective Studies; Radiography; Radiopharmaceuticals; Retrospective Studies; Severity of Illness Index; Stroke; Technetium Tc 99m Exametazime; Time Factors

A meta-analysis of SPECT brain imaging in epilepsy was performed to derive the sensitivity and specificity of interictal, postictal or ictal rCBF patterns to identify a seizure focus in medically refractory patients.. Papers were obtained by pooling all published articles identified by two independent literature searches: (a) Dialnet (EMBASE) or Radline by CD-ROM and (b) Current Contents searched manually. Literature inclusion criteria were: (a) patients had a localization-related epileptic syndrome; (b) more than six patients were reported; and (c) patients had at least an interictal EEG-documented epileptiform abnormality. Of 46 papers meeting these criteria, 30 contained extractable data. SPECT results were compared to localization by standard diagnostic evaluation and surgical outcome. Meta-analytic sensitivities for SPECT localization in patients with temporal lobe seizures relative to diagnostic evaluation were 0.44 (interictal), 0.75 (postictal) and 0.97 (ictal). Similar results were obtained relative to surgical outcome. False-positive rates were low relative to diagnostic evaluation (7.4% for interictal and 1.5% for postictal studies) and surgical outcome (4.4% for interictal and 0.0% for postictal studies).. The results were not dependent on tracer used (or dose), the presence of CT-identified structural abnormalities, blinding of image interpretation or camera quality (although data were more variable with low-resolution cameras). There were insufficient data for conclusions regarding extratemporal-seizure or pediatric epilepsy populations.. Insights gained from reviewing this literature yielded recommendations for minimal information that should be provided in future reports. Additional recommendations regarding the nature and focus of future studies also are provided. The most important of these is that institutions using SPECT imaging in epilepsy should perform ictal, preferably, or postictal scanning in combination with interictal scanning.

Topics: Brain; Electroencephalography; Epilepsy; False Positive Reactions; Humans; Radiopharmaceuticals; Sensitivity and Specificity; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

MRI has been applied to the investigation of epilepsy for 12 years. The principle role of MRI is in the definition of structural abnormalities that underly seizure disorders. Hippocampal sclerosis may be reliably identified, quantitative studies are useful for research and, in equivocal cases, for clinical purposes. A range of malformations of cortical development (MCD) may be determined. In patients with refractory partial seizures who are candidates for surgical treatment, a relevant abnormality is identifiable using MRI in 85%, it is likely that subtle MCD or gliosis accounts for the majority of the remainder. The proportion of cryptogenic cases will decrease with improvements in MRI hardware, signal acquisition techniques and post-processing methodologies. Functional MRI is used to identify the cerebral areas that are responsible for specific cognitive processes, and is of importance in planning resections close to eloquent cortical areas. Magnetic resonance spectroscopy (MRS) provides a means of investigating cerebral metabolites and some neurotransmitters, non-invasively. The concentrations of N-acetyl-aspartate (NAA), creatine and choline-containing compounds may be estimated using proton MRS. Reduction of the ratio of NAA/(creatine+choline) is a feature of cerebral regions that include epileptic foci. Cerebral concentrations of GABA and glutamate, and the effects of antiepileptic drugs on these, may be estimated. Concentrations of high energy phosphate compounds, inorganic phosphate and pH may be assessed using 31P-MRS. In general, epileptic foci are associated with an increase in pH, increased inorganic phosphate and decreased phosphate monoesters. Carbon-13 spectroscopy promises to be a useful method for investigating cerebral metabolism in vivo. PET may provide data on regional cerebral blood flow (rCBF), glucose metabolism and the binding of specific ligands to receptors. Correlation of functional and structural imaging data is necessary for adequate interpretation. The hallmark of an epileptic focus is an area of reduced glucose metabolism, identified using [18F]fluorodeoxyglucose (18FDG), that is commonly more extensive than the underlying anatomical abnormality. The clinical role of 18FDG-PET requires re-evaluation in the light of the advances in structural imaging with MRI. Specific ligands are used to investigate specific receptors. Benzodiazepine and opioid receptors have been studied most. Reduced benzodiazepine receptor binding is comm

Topics: Cerebral Cortex; Cerebrovascular Circulation; Deoxyglucose; Epilepsy; Flumazenil; Fluorodeoxyglucose F18; Glucose; Hippocampus; Humans; Ligands; Magnetic Resonance Imaging; Magnetic Resonance Spectroscopy; Nervous System Neoplasms; Organotechnetium Compounds; Oximes; Receptors, GABA-A; Receptors, Opioid; Technetium Tc 99m Exametazime; Tomography, Emission-Computed; Tomography, Emission-Computed, Single-Photon

Recent and future evolutions in neuroSPECT apply to radiopharmaceuticals techniques and the synergistic use of different imaging modalities in the work-up of neurological disorders. The introduction of Technetium labelled perfusion tracers, which could pass the intact blood-brain barrier, together with the implementation of the tomographic principle, by making the conventional gamma camera rotating, enabled estimation of regional cerebral blood flow and indirectly of local brain metabolism. In addition at present Thallium-201 and Tc-99m sestaMIBI allow functional detection of viable tumor tissue, without interference from previous surgery or radiotherapy as seen using CT-scan or MRI. In neurology this has led to the recognition of SPECT by the American Academy of Neurology (Therapeutics and technology subcommittee) as an established or promising tool in major neurological disorders such as dementia, stroke and epilepsy, while other domains such as brain oncology are considered investigational. With regard to radiopharmaceuticals, recent evolutions mainly include the development of mostly Iodine-123 labelled receptor ligands, some of which are already commercially available. For instrumentation advances consist e.g. of multidetector systems equipped with fanbeam collimators, attenuation and scatter correction or coincidence detection. Given the present role for nuclear neurology it may be expected that these additional radiopharmaceutical and technical innovations will continue to stimulate the development of SPECT of the brain. The synergistic use of several imaging techniques such as CT, (functional) MRI, source imaging, SPECT and PET represents a multimodal holistic approach to probe cerebral functions for research and clinical purposes. Clinical indications, in which this synergistic use is illustrated include e.g. support of the clinical diagnosis of dementia of the Alzheimer type, presurgical ictal detection of seizure focus, detection of acute ischemia and differential diagnosis between radiation necrosis and brain tumor recurrence. The synergistic use of imaging modalities, optimally applied using image fusion, allows to overcome the intrinsic limitations and to enhance the specific advantages of the different approaches as it leads to increased precision and accuracy, as well for spatial anatomofunctional correlation as for quantification.

Topics: Alzheimer Disease; Brain Ischemia; Brain Neoplasms; Epilepsy; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Mental Disorders; Nervous System Diseases; Neurology; Nitriles; Technetium Tc 99m Exametazime; Tomography, Emission-Computed; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed

Brain SPECT with HMPAO or ECD has-due to its short accumulation period--a rather high time resolution of approx 60 sec. Compared to isopropyl amphetamine (I-123) and FDG-PET, shortlasting interventions may be evaluated by SPECT. Usually, a two-step approach is used, injecting one third of the dose under baseline conditions and two thirds during intervention. The first study is then subtracted from the second study, resulting in a "difference" image which allows to calculate the effect of the intervention. These interventional procedures may include drug, mechanical, and mental intervention as well as ictal, blood pressure and receptor intervention. Moreover, the difference of pCO2 after hyperventilation or hypoventilation may also be used as a stimulus. The above mentioned procedures are described in detail.

Topics: Brain; Cerebrovascular Circulation; Deoxyglucose; Depressive Disorder; Epilepsy; Fluorine Radioisotopes; Fluorodeoxyglucose F18; Humans; Iodine Radioisotopes; Organotechnetium Compounds; Oximes; Schizophrenia; Technetium Tc 99m Exametazime; 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

Topics: Brain Diseases; Brain Neoplasms; Child; Deoxyglucose; Epilepsy; Fluorine Radioisotopes; Fluorodeoxyglucose F18; Humans; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Technetium Tc 99m Sestamibi; Thallium Radioisotopes; Tomography, Emission-Computed; Tomography, Emission-Computed, Single-Photon

Regional cerebral blood flow can be measured using single photon emission computed tomography (SPECT). Hexamethyl propyleneamine oxime (HMPAO) is commercially available as a 99mTc-labeled tracer and has the advantage of fixing a blood flow pattern during its first passage through the capillaries. This can be used, for example, to evaluate a short-term ictal phase. With dedicated SPECT systems a spatial resolution of 5-8 mm can be achieved. Measurement using 133Xe allows absolute quantification of blood flow values, but the spatial resolution is lower. In about 50-70% of patients suffering from temporal lobe epilepsy a decreased blood flow in the focus can be visualized in the interictal phase. Ictally, focal hyperperfusion can be observed in most cases. The sensitivity and specificity of SPECT in the ictal phase are superior compared with interictal study. During the postictal phase a hyperperfusion of the anterior and mesial parts of the affected temporal lobe with simultaneous lateral hypoperfusion can often be demonstrated. At present, receptor SPECT has not yet reached clinical significance in the diagnosis of epilepsy.

Topics: Brain; Epilepsy; Humans; Organotechnetium Compounds; Oximes; Regional Blood Flow; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

The imaging of regional cerebral blood flow (rCBF) by 99mTc-d, 1 HM-PAO and SPECT is described. Its relevance to clinical syndromes, such as stroke, transient ischemic attacks, various forms of dementia, epilepsy, and subarachnoid hemorrhage, is reported.

Topics: Animals; Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Chemical Phenomena; Chemistry; Dementia; Epilepsy; Humans; Ischemic Attack, Transient; Organometallic Compounds; Organotechnetium Compounds; Oximes; Subarachnoid Hemorrhage; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

Vagus nerve stimulation (VNS) has gained recognition as a treatment for refractory epilepsies where surgical treatment is not possible. While it appears that this treatment is effective in some patients, the mechanism of action is not clearly understood. The purpose of this study was to clarify findings of other positron emission tomography and single-photon emission tomography (SPET) investigations by measuring the acute effect of VNS on patients who have normal cerebral anatomy on magnetic resonance imaging and who have not previously been exposed to VNS. We investigated six subjects (two males and four females, mean age 29.5 years, range 21-39 years) with intractable epilepsy. One patient had primary generalised epilepsy causing generalised tonic-clonic seizures; the remaining five patients had localisation-related epilepsy causing complex partial seizures. SPET imaging was performed using 250 MBq of (99m)Tc-HMPAO and a four-scan paradigm - two with and two without stimulation. The stimulation began at VNS current levels of 0.25 mA and was increased according to the limit of patients' tolerance, usually defined by coughing or discomfort. The stimulating waveform was of continuous square wave pulses of 500 micro s duration at 30 Hz. Image analysis was by SPM99. Reduced perfusion during stimulation was observed in the ipsilateral brain stem, cingulate, amygdala and hippocampus and contralateral thalamus and cingulate. The study provides further evidence of the involvement of the limbic system in the action of vagal nerve stimulation.

Topics: Adult; Brain; Cerebrovascular Circulation; Chronic Disease; Electric Stimulation Therapy; Epilepsy; Female; Humans; Limbic System; Male; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Vagus Nerve

We tested the prediction that single photon emission computed tomography (SPECT) of the blood flow distribution in speech-activated brain identifies the language-dominant hemisphere. We based the prediction on the hypothesis that language activation leads to focally increased regional cerebral blood flow (rCBF), which is reflected in the uptake of a flow tracer recorded by SPECT. We compared the results of speech activation to the results of functional transcranial Doppler (fTCD) monitoring in the same subjects. Preoperatively, 17 patients (10 women and 7 men with a mean age of 36 +/- 15 years) with diagnoses of epilepsy (n = 14) or arteriovenous malformation (AVM) (n = 3) had two SPECT and two stereo-TCD monitoring studies in each case, one at rest, and one during 3 min of speech activation. Except for two left-handed patients with right-hemisphere dominance, the subjects had the highest changes of rCBF from baseline to activation in the left posterior inferior frontal cortex and in contralateral cerebellum. The results show that changes of the level of neuronal activity reflected by the measurement of rCBF variations might be detected by SPECT. Additionally, the evaluation of hemispheric language dominance based on SPECT showed a complete agreement with the evaluation based on fTCD results (yielding a kappa coefficient equal to 1), and therefore, speech-activation SPECT mapping might be helpful in the evaluation of hemispheric language dominance, especially when fMRI and PET are not available or they are contraindicated for some reason.

Topics: Adolescent; Adult; Brain; Dominance, Cerebral; Epilepsy; Female; Functional Laterality; Humans; Male; Middle Aged; Radiopharmaceuticals; Speech; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Ultrasonography, Doppler, Transcranial

We performed interictal brain 99m Tc-HMPAO study in eight cases of chronic epilepsy. SPECT (single photon emission computed tomography) study showed abnormality in seven cases. As compared to computed tomography (CT) scan and electroencephalogram (EEG) which were positive in 25% and 62% cases respectively it showed abnormality in 87%. In two cases where CT scan and EEG both were normal, SPECT showed areas of hypoperfusion. In one case where EEG indicated a bilateral focus, SPECT study showed a clearly defined unilateral focal hypoperfusion defect. Areas of hyperperfusion were not seen in any of our cases. Our results indicate that HMPAO SPECT is more sensitive than CT scan and EEG, in localising an epileptogenic focus in cases of chronic epilepsy.

Topics: Adolescent; Adult; Brain; Child; Chronic Disease; Epilepsy; Humans; Male; Sensitivity and Specificity; Severity of Illness Index; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Firstly, to compare the findings of interictal 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) and of single photon emission computed tomography (SPECT) using 99mTc-hexamethyl propylene-amine-oxime (HMPAO) and 123I-iomazenil in localising the epileptogenic cortex in patients who were candidates for epilepsy surgery, but in whom clinical findings, video EEG monitoring (V-EEG), MRI, and neuropsychological evaluations did not give any definite localisation of the seizure onset. Secondly, to assess the ability of these functional methods to help in the decision about the epilepsy surgery.. Eighteen epileptic patients were studied with FDG-PET and iomazenil-SPECT. HMPAO-SPECT was performed in 11 of these 18 patients. Two references for localisation was used--ictal subdural EEG recordings (S-EEG) and the operated region.. Fifteen of 18 patients had localising findings in S-EEG. FDG-PET findings were in accordance with the references in 13 patients and iomazenil-SPECT in nine patients. HMPAO-SPECT visualised the focus less accurately than the two other methods. In three patients S-EEG showed independent bitemporal seizure onset. In these patients FDG-PET showed no lateralisation. However, iomazenil-SPECT showed temporal lobe lateralisation in two of them.. FDG-PET seemed to localise the epileptogenic cortex more accurately than interictal iomazenil-SPECT in patients with complicated focal epilepsy.

Topics: Adolescent; Adult; Atrophy; Cerebral Cortex; Electroencephalography; Epilepsy; Female; Flumazenil; Fluorodeoxyglucose F18; Glucose; Humans; Magnetic Resonance Imaging; Male; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed; Tomography, Emission-Computed, Single-Photon

Topics: Adolescent; Adult; Child; Child, Preschool; Deoxyglucose; Electric Stimulation; Electroencephalography; Epilepsy; Female; Fluorodeoxyglucose F18; Humans; Infant; Magnetic Resonance Imaging; Male; Motor Cortex; Organotechnetium Compounds; Oximes; Somatosensory Cortex; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

This retrospective study investigates the predictive value of ictal subtraction single-photon emission computed tomography (SPECT) co-registered to magnetic resonance imaging (MRI) (SISCOM) for successful epilepsy surgery.. 57 patients examined with SISCOM as a part of epilepsy surgery evaluation were divided into two groups based on seizure duration after tracer injection (group 1: Seizure duration above or equal to 30 s, group 2: Seizure duration under 30 s). SISCOM was compared to the surgical site and categorized as good or poor concordance. Subsequently, Odds ratios (ORs) and positive predictive values (PPVs) were calculated for each group for good surgical outcome, freedom from disabling seizures.. The PPVs and ORs for good surgical outcome was 74.1% and 5.71 for group 1 and 40% and 0.22 for group 2. SISCOM had a similar positive predictive value regardless of whether the focus was in the same or neighboring lobe, but same hemisphere as the resection.. In conclusion, the implementation of a precise definition for a well-executed ictal SPECT scan with respect to seizure duration after injection enhances the positive predictive value (PPV) and odds ratio (OR) for successful surgical outcome, surpassing previous findings, whether the focus in resected lobe or the neighboring.

Topics: Epilepsy; Humans; Retrospective Studies; Seizures; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Single-photon emission computed tomography (SPECT) with the tracer. Fifty-six patients operated for epilepsy who had been investigated with SISCOM were included in the analysis. The patients were divided into two groups based on seizure duration after tracer injection, above or below 30 s. The preoperative SISCOM description was compared to the area of resection and given a concordance score. The 56 SISCOM were recalculated visualizing also areas of hypoperfusion and again compared to the site of resection using the same scale of concordance. The reversed SISCOM were categorized into three subgroups: "Altered Conclusion," "Confirmed Conclusion," and "Adds Nothing." If an area of hyperperfusion had an area of hypoperfusion in close proximity, it was re-interpreted as noise, thus possibly altering the conclusion. If the areas of hypoperfusion were in the opposite hemisphere it was interpreted as confirming factor. Further the concordance scores from conventional SISCOM and reversed SISCOM was compared to surgical outcome to explore the difference in sensitivity, positive predictive value (PPV), and odds ratio.. In approximately half of the cases reversed SISCOM added additional value, meaning either altered the conclusion or confirmed the conclusion. The sensitivity, PPV, and odds ratio was also better in the subgroup of long, >30 s seizure duration after injection, and got worse in the group with short, <30 s seizure duration after injection.. Adding reversed SISCOM performed better than conventional SISCOM at predicting good surgical outcome.

Topics: Epilepsy; Humans; Retrospective Studies; Seizures; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

A 55-year-old woman was diagnosed with the syndrome of mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS). She was referred for Tc-HMPAO brain SPECT because of visual hallucinations, which were suspected to be related to epileptic seizures. Ictal SPECT images showed remarkable hyperperfusion in the left occipital cortex, which returned to near-normal status on the interictal SPECT images after treatment with anticonvulsants. It is very rare to see such an ictal SPECT image of epileptic or epilepsy-like disorders, especially in the setting of MELAS syndrome with visual hallucination.

Topics: Brain; Epilepsy; Female; Hallucinations; Humans; MELAS Syndrome; Middle Aged; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

The cause or the physiological role of déjà vu (DV) in healthy people is unknown. The pathophysiology of DV-type epileptic aura is also unresolved. Here we describe a 22-year-old woman treated with deep brain stimulation (DBS) of the left internal globus pallidus for hemidystonia. At certain stimulation settings, DBS elicited reproducible episodes of DV.. Neuropsychological tests and single-photon-emission computed tomography (SPECT) were performed during DBS-evoked DV and during normal DBS stimulation without DV.. SPECT during DBS-evoked DV revealed hyperperfusion of the right (contralateral to the electrode) hippocampus and other limbic structures. Neuropsychological examinations performed during several evoked DV episodes revealed disturbances in nonverbal memory.. Our results confirm the role of mesiotemporal structures in the pathogenesis of DV. We hypothesize that individual neuroanatomy and disturbances in gamma oscillations or in the dopaminergic system played a role in DBS-elicited DV in our patient.

Topics: Cognition; Deep Brain Stimulation; Deja Vu; Epilepsy; Female; Globus Pallidus; Humans; Magnetic Resonance Imaging; Neuropsychological Tests; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Young Adult

[Case records of Epileptic Disorders. Anatomo-electro clinical correlations. Case 01-2009]. Tuberous sclerosis complex (TSC) is a multisystem genetic disorder with variable phenotypic expression, caused by mutations in one of the two tumor suppressor genes, TSC1 or TSC2. Epilepsy is the most common neurological presentation and seizures are often medically intractable. Definition of the epileptogenic zone during presurgical evaluation is challenging given the multiple potentially epileptogenic lesions visible on MRI. However, TSC patients may nevertheless achieve seizure freedom, when preoperative evaluation yields concordant results. The strategies used in these patients vary substantially among different epilepsy surgery centres. We present a 21-year-old right-handed, intellectually not impaired woman with TSC and medically intractable seizures since the age of 15 years. Careful multi-stage presurgical evaluation, including prolonged video-EEG-monitoring, cerebral high resolution MRI, ictal and interictal [99m Tc]HMPAO-SPECT, [18 F]FDG-PET and further invasive recordings with subdural and depth electrodes led to the identification of an epileptogenic tuber with concordant seizure onset zone in the right neocortical temporal lobe. A tailored resection was performed leading to excellent surgical outcome (follow-up 12 months, Engel class I).

Topics: Age of Onset; Brain; Electroencephalography; Epilepsy; Female; Fluorodeoxyglucose F18; Humans; Magnetic Resonance Imaging; Neurosurgical Procedures; Positron-Emission Tomography; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon; Treatment Outcome; Tuberous Sclerosis; Young Adult

Ictal single-photon emission computed tomography (SPECT) is a valuable method for localizing the ictal onset zone in the presurgical evaluation of patients with intractable epilepsy. Conventional methods used to localize the ictal onset zone have problems with time lag from seizure onset to injection.. To evaluate the clinical usefulness of a method that we developed, which involves an attachable automated injector (AAI), in reducing time lag and improving the ability to localize the zone of seizure onset.. Patients admitted to the epilepsy monitoring unit (EMU) between January 1, 2003, and June 30, 2008, were included. The definition of ictal onset zone was made by comprehensive review of medical records, magnetic resonance imaging (MRI), data from video electroencephalography (EEG) monitoring, and invasive EEG monitoring if available. We comprehensively evaluated the time lag to injection and the image patterns of ictal SPECT using traditional visual analysis, statistical parametric mapping-assisted, and subtraction ictal SPECT coregistered to an MRI-assisted means of analysis. Image patterns were classified as localizing, lateralizing, and nonlateralizing. The whole number of patients was 99: 48 in the conventional group and 51 in the AAI group.. The mean (SD) delay time to injection from seizure onset was 12.4+/-12.0 s in the group injected by our AAI method and 40.4+/-26.3 s in the group injected by the conventional method (P=0.000). The mean delay time to injection from seizure detection was 3.2+/-2.5 s in the group injected by the AAI method and 21.4+/-9.7 s in the group injected by the conventional method (P=0.000). The AAI method was superior to the conventional method in localizing the area of seizure onset (36 out of 51 with AAI method vs. 21 out of 48 with conventional method, P=0.009), especially in non-temporal lobe epilepsy (non-TLE) patients (17 out of 27 with AAI method vs. 3 out of 13 with conventional method, P=0.041), and in lateralizing the seizure onset hemisphere (47 out of 51 with AAI method vs. 33 out of 48 with conventional method, P=0.004).. The AAI method was superior to the conventional method in reducing the time lag of tracer injection and in localizing and lateralizing the ictal onset zone, especially in patients with non-TLE.

Topics: Adolescent; Adult; Child; Electroencephalography; Epilepsy; Female; Humans; Injections; Magnetic Resonance Imaging; Male; Middle Aged; Radiopharmaceuticals; Retrospective Studies; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Ictal propagation to the cortical and subcortical structures is well known in mesial temporal epilepsy (MTE) and neocortical epilepsy (NE). We analyzed the ictal changes of regional blood flow in limbic-related cortical and subcortical structures to evaluate the differences in ictal propagation patterns between MTE and NE.. In 65 patients (mean age, 29.1+/-10.83 years) with intractable MTE (n=46) or NE (n=19), ictal 99m-Tc ethyl cystinate dimer SPECT was performed. A subtracted ictal SPECT coregistered to MRI images was obtained in each patient. The patterns of subtracted ictal hyperperfusion in the limbic, paralimbic and subcortical structures in patients with MTE and NE were compared.. The ictal hyperperfusion of the amygdala, hippocampus, temporal pole and insula were significantly higher in MTE (P<0.01), but cingulate and orbitofrontal hyperperfusion were not. A significant difference in striatal ictal hyperperfusion between the MTE and NE group was found (P=0.035). Ictal hyperperfusion of NE was greater in the superior part (P=0.011), whereas that of MTE was greater in the inferior and middle parts.. These findings suggest that the ictal propagation of MTE may differ from that of NE via different pathways not only in the cortical regions but also in the subcortical structures.

Topics: Adolescent; Adult; Brain Mapping; Child; Child, Preschool; Electroencephalography; Epilepsy; Female; Humans; Limbic System; Magnetic Resonance Imaging; Male; Neocortex; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon; Young Adult

To correlate ictal hyperperfusion single-photon emission computed tomography (SPECT) area during provoked seizures to the epileptogenic zone (EZ), as defined by depth recordings in adult drug-resistant patients.. We included in the study eight drug-resistant epilepsy patients, subjected to both noninvasive and invasive (stereo-electroencephalography, SEEG) presurgical evaluation in the Epilepsy Surgery Center of the Catholic University in Rome, from 2001 to 2003. All patients were subjected to interictal and provoked ictal SPECT scans during scalp video-EEG monitoring. The ictal hyperperfusion area assessed by visual image analysis and, when possible, by statistical parametric mapping (SPM), was compared with the EZ, as assessed by SEEG, to define whether they colocalized.. For each provoked seizure, we obtained a SPECT hyperperfusion area. In five patients, the SPECT hyperperfusion area was included in the EZ as assessed by SEEG. The effectiveness of provoked SPECT was confirmed by comparison with SEEG data, SPM analysis (four patients), and spontaneous ictal SPECT (two patients). Our data were obtained in adult drug-resistant epilepsy patients whose EZ was either located in or extended to extratemporal regions in all but two patients.. Provoked ictal SPECT confirmed its efficacy and accuracy in the presurgical evaluation because of the colocalization to the EZ. Although the low number of patients precluded any statistical correlation with the surgical outcome, it is worth pointing out that the five patients in whom the hyperperfusion area was included in the EZ showed very satisfactory results.

Topics: Adult; Brain Mapping; Cerebral Cortex; Drug Resistance; Electrodes, Implanted; Electroencephalography; Epilepsy; Female; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Male; Monitoring, Physiologic; Pentylenetetrazole; Preoperative Care; Regional Blood Flow; Stereotaxic Techniques; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Videotape Recording

To assess the additional value of subtraction ictal single-photon emission computed tomography (SPECT) coregistered to MRI (SISCOM) for localization of the epileptogenic zone in patients with drug-resistant epilepsy scheduled for invasive video-EEG (VEEG) before epilepsy surgery by a descriptive study from clinical practice.. Forty-nine consecutive epilepsy patients between January 2000 and March 2006 were included. Thirty-six of the 49 patients were offered surgery, and 34 underwent resective surgery during the study period. Localizing and outcome data are presented from 31 patients with a follow-up period of >or=12 months. Successful ictal SPECT was performed in 26 patients, and SISCOM showed significant hyperperfusions with 3.5 SD above reference. Twenty patients had SISCOM-guided electrode placement, invasive monitoring, and 1-year postsurgical follow-up data. Two independent epileptologists evaluated whether SISCOM results (a) altered the hypothesis and extended the strategy for electrode placement at invasive recording, or (b) were confirmatory of other localizing data and did not alter the strategy. We defined that SISCOM had an impact on seizure outcome if the seizure-onset zone was seen in electrodes overlying a brain region with a significant hyperperfusion. When SISCOM was concordant with ictal onset in the extended electrodes, SISCOM was considered a prerequisite for the outcome at postoperative follow-up.. SISCOM findings altered and extended the strategy for electrode placement at invasive recording in 15 patients (group A). SISCOM was a prerequisite for seizure outcome in all six patients with favorable outcomes. Nine patients had poor results from surgery in this group; SISCOM was concordant with invasive VEEG in six patients, and discordant with invasive VEEG in three patients. SISCOM findings were confirmatory with other localizing data and did not alter the strategy at invasive recording in five patients (group B). Two patients had favorable surgical outcomes. In this group, three patients had poor results; SISCOM and other localizing findings were concordant with invasive VEEG in one patient and discordant with invasive VEEG in two patients.. SISCOM is valuable for the identification of the epileptogenic zone in patients with drug-resistant epilepsy scheduled for invasive VEEG. SISCOM analysis was either a prerequisite for favorable result or concordant with other localizing methods in all patients with favorable seizure outcome at 1 year of follow-up [40%; confidence interval (CI), 19-64).

Topics: Adolescent; Adult; Brain Mapping; Cerebral Cortex; Child; Child, Preschool; Electrodes, Implanted; Electroencephalography; Epilepsy; Female; Follow-Up Studies; Functional Laterality; Humans; Image Interpretation, Computer-Assisted; Longitudinal Studies; Magnetic Resonance Imaging; Male; Middle Aged; Stereotaxic Techniques; Subtraction Technique; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Treatment Outcome; Videotape Recording

Functional neuroimaging can address some challenges of seizure localization, and sometimes preclude the need for EEG recording using intracranial electrodes. Ictal Single Photon Emission Computed Tomography (SPECT) has developed into an important tool in the presurgical evaluation of patients with medically-intractable localization-related epilepsy. The purpose of the study was to determine whether the development of a programme using trained nurses to perform ictal injections enabled a more efficient delivery of radiopharmaceuticals and therefore a greater sensitivity and specificity of outcome.. In our epilepsy unit, nursing staff inject 99mTc-HMPAO at bedside, during or at seizure onset. Brain SPECT is performed later on a gamma camera.. Since the implementation of the new protocol (February 2005), 57 scans have been performed: 22 ictal and 35 interictal. Latency of ictal injection was found to be 5-40 seconds (mean 19.7 sec, standard deviation (SD) 10.4). Only 20% of reconstituted radiopharmaceutical vials were not used. Contamination rate was nil. Sixty three percent of SPECT studies were concordant with standard presurgical evaluation.. The latency of injections and the percentage of unused vials indicated an efficient and effective protocol compared to the literature. Our results show that ictal SPECT can be a safe, noninvasive procedure performed on a routine basis in the epilepsy unit when appropriately trained support staff are incorporated into a structured multidisciplinary programme.

Topics: Brain; Brain Mapping; Canada; Epilepsy; Humans; Nursing Staff, Hospital; Radiopharmaceuticals; Seizures; Staff Development; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Periodic lateralized epileptiform discharges (PLEDs), which are known as unusual electroencephalogram (EEG) patterns, are described in a patient who had stroke and seizures. This patient underwent Tc-99m HMPAO (hexamethyl propylene amine oxime) brain single photon emission computed tomography (SPECT) imaging both during PLEDs on EEG and after the cessation of PLEDs. The initial SPECT study revealed increased CBF in the left frontal and parietal cortex extending through the left temporal region and in the left basal ganglium. After the PLEDs disappeared, the second SPECT study showed decreased perfusion on the left frontal and parietal region in the brain. Brain SPECT findings supported the contention that PLEDs may be an ictal phenomenon. Here we also present a review on PLEDs and contributions of brain SPECT as a functional imaging modality to investigate the underlying mechanism of this interesting EEG pattern.

Topics: Aged; Brain; Brain Mapping; Epilepsy; Humans; Male; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

In recent years, it has been possible for patients with Down syndrome to live longer with advanced medical treatment and social support. As a result, the problems of these patients, such as thyroid diseases, leukemia, and Alzheimer disease, would be encountered more frequently. In this study, we aimed to perform the brain perfusion of children with Down syndrome by technetium 99m hexamethylpropylene amine oxime (99mTc-HMPAO) single-photon emission computed tomography (SPECT) and to determine the relationship between brain perfusion and epilepsy, thyroid function tests, congenital heart disease, and level of mental and motor development. Thirty patients with Down syndrome, aged between 1 and 15 years, were included in our study. Demographic data, the existence of epilepsy and congenital heart defects, the level of mental and motor development, serum levels of thyroid hormones, and autoantibodies were determined. All patients underwent computed tomography (CT) and/or magnetic resonance imaging (MRI). Cerebral SPECT was performed in all cases to evaluate the brain perfusion pattern. According to the visual evaluation of cerebral SPECT results, hypoperfusion was detected in 11 cases (37%). Patients with cerebral hypoperfusion (group 1) and patients with normal cerebral perfusion (group 2) were compared. There was no difference between group 1 and group 2 in terms of demographic data, congenital heart defects, IQ levels, thyroid hormones, and autoantibodies, but the incidence of epilepsy was significantly higher in group 1 (P<.001). When motor and mental development levels were compared, it was found that cases in group 1 were significantly more retarded in personal-social and fine motor skills (P<.05). The present study showed that cerebral hypoperfusion in children with Down syndrome is mostly related to epilepsy and the other coexisting conditions, congenital heart disease and hypothyroidism. Patients with cerebral hypoperfusion also have more retarded developmental levels, especially in personal-social and fine motor skills.

Topics: Adolescent; Cerebrovascular Circulation; Child; Child Development; Child, Preschool; Down Syndrome; Epilepsy; Female; Heart Defects, Congenital; Humans; Hypothyroidism; Infant; Intelligence; Male; Motor Skills; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Hyperglycemia may rarely be seen with visual seizures. Observation of both visual evoked potentials (VEPs) and magnetic resonance imaging (MRI) in visual status epilepticus (SE) has not been reported. We describe acute and follow-up VEP and MRI findings of a patient with hyperglycemia-related visual SE of occipital origin.. In a 59-year-old diabetic woman, complex visual hallucinations and illusions developed with < or =10 seizures per hour as an initial manifestation of nonketotic hyperglycemia.. Neurologic examination revealed ictal nystagmus to the right and continuous right hemianopsia. Ictal electroencephalography (EEG) and Tc-99m hexamethylpropylene amine oxime (HMPAO) single-photon emission computed tomography (SPECT) revealed an epileptogenic focus in the left occipital lobe. MRI with fluid-attenuated inversion recovery showed focal subcortical hypointensity and gyral hyperintensity. Follow-up MRI showed only minimal gyral hyperintensity at 6 months. The P100 amplitude of VEP was significantly higher at the right occipital area during SE, but slightly higher on the left after the patient had been seizure free for 6 months.. Occipital seizures and hemianopsia can be caused by hyperglycemia and may be accompanied by special MRI and VEP findings.

Topics: Electroencephalography; Epilepsy; Evoked Potentials, Visual; Female; Functional Laterality; Hallucinations; Hemianopsia; Humans; Hyperglycemia; Illusions; Magnetic Resonance Imaging; Middle Aged; Occipital Lobe; Status Epilepticus; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Surgical treatment of cryptogenic neocortical epilepsy is challenging. The aim of this study was to evaluate surgical outcomes and to identify possible prognostic factors including the results of various diagnostic tools. Eighty-nine patients with neocortical epilepsy with normal magnetic resonance imaging (35 patients with frontal lobe epilepsy, 31 with neocortical temporal lobe epilepsy, 11 with occipital lobe epilepsy, 11 with parietal lobe epilepsy, and 1 with multifocal epilepsy) underwent invasive study and focal surgical resection. Patients were observed for at least 2 years after surgery. The localizing values of interictal electroencephalogram (EEG), ictal scalp EEG, interictal 18F-fluorodeoxyglucose positron emission tomography (FDG-PET), and subtraction ictal single-photon emission computed tomography were evaluated. Seventy-one patients (80.0%) had a good surgical outcome (Engel class 1-3); 42 patients were seizure free. Diagnostic sensitivities of interictal EEG, ictal scalp EEG, FDG-PET, and subtraction ictal single-photon emission computed tomography were 37.1%, 70.8%, 44.3%, and 41.1%, respectively. Localization by FDG-PET and interictal EEG was correlated with a seizure-free outcome. The localizing value of FDG-PET was greatest in neocortical temporal lobe epilepsy. The focalization of ictal onset and also ictal onset frequency in invasive studies were not related to surgical outcome. Concordance with two or more presurgical evaluations was significantly related to a seizure-free outcome.

Topics: Adolescent; Adult; Child; Disease Progression; Electroencephalography; Epilepsy; Female; Follow-Up Studies; Humans; Male; Middle Aged; Neurosurgery; Positron-Emission Tomography; Retrospective Studies; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Treatment Outcome

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

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

Band heterotopias are an example of genetic generalized neuronal migration disorders that may be present in patients with mild epilepsy and normal or slightly impaired intellect, as well as in patients with intractable epilepsy and mental retardation. The case of a 17-year-old left-handed female patient with epilepsy and normal cognitive development is reported in whom single-photon emission computed tomography (SPECT), proton magnetic resonance spectroscopy, and functional magnetic resonance imaging (fMRI) were performed. MRI revealed the presence of bilateral asymmetric band heterotopia. SPECT revealed a left frontoparietal and occipital hypoperfusion, demonstrating a good correlation with the electroencephalogram abnormalities. Because of the appearance of new types of seizures, the patient underwent a second MRI investigation together with a proton magnetic resonance spectroscopy (MRS) study. MRI confirmed bilateral band heterotopia characterized by greater thickness in the left hemisphere at the frontal and occipital level. MRI and SPECT findings were in agreement with left occipital electroencephalogram abnormalities and with occipital seizure type. Qualitative results of proton MRS revealed normal spectra profiles in the examined left frontal and occipital heterotopic area and in the normal overlying cortex. Later, fMRI was performed. The finger-tapping test of the right hand yielded the activation of both normal left sensory-motor cortex and the facing band heterotopia. In the right hemisphere, only the activation of the sensory-motor neocortex was observed; no involvement of the right misplaced brain tissue was present. This functional behavior could be considered the consequence of poor neuronal representation. On the contrary, the involvement of both band heterotopia and normal cortex observed in the left hemisphere could be the result of many synaptic interconnections. Functional investigations may have an important role in defining the activity of band heterotopia per se and in relation to the overlying neocortex.

Topics: Adolescent; Brain; Brain Diseases; Cell Movement; Choristoma; Dominance, Cerebral; Epilepsy; Female; Humans; Intelligence; Magnetic Resonance Imaging; Mutation, Missense; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

This paper examines a solution to the general problem of accurately relating points within functional data acquired before and after subdural intracranial electrode implantation. We develop an approach based on nonrigid registration of high resolution anatomical MRI acquired together with the functional data. This makes use of a free-form B-Spline deformation model and registration is recovered by maximizing the normalized mutual information between the preimplant MRI and the postimplant MRI. We apply the approach to estimate the tissue deformation induced by the presence of intracranial electrodes over 15 patient studies. Maximum tissue displacements of 4 mm or greater were observed in all cases either in the cortex or around the ventricles due to CSF loss. In studies involving larger 4 x 4 grids, local tissue displacement estimates exceeded 10 mm from the preimplant brain shape. The key issue with this approach is whether the deformation estimates are contaminated by the presence of susceptibility-induced imaging artifacts. We therefore evaluate the deformation estimates in recovering alignment of essentially identical SPECT studies of eight patients acquired before and after electrode placement. An ROI-based analysis of the variance of resulting subtraction values between pre- and postimplant SPECT was carried out in regions of tissue below electrode grids. Results indicate for all cases a substantial reduction in residual SPECT subtraction artifacts to a level comparable to that in an equivalent region of undeformed tissue.

Topics: Adolescent; Adult; Brain; Child; Electrodes, Implanted; Epilepsy; Humans; Magnetic Resonance Imaging; Middle Aged; Models, Neurological; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Intractable epilepsies pose a therapeutic challenge. Precise localization of the epileptic focus is imperative before planning surgical intervention. Functional imaging is an important component of presurgical work-up. Positron emission tomography is unavailable in developing countries; hence, the need to evaluate the available imaging modality, single photon emission computed tomography (SPECT), was felt. We investigated 61 children with intractable epilepsy, identified by predefined criteria, by performing electroencephalography (EEG), magnetic resonance imaging (MRI), computed tomography (CT), and ictal and interictal SPECT. The localizing value of ictal and interictal SPECT imaging for epileptic foci was correlated with clinical, electrophysiologic, and anatomic neuroimaging data. An ictal SPECT was obtained in 9, and interictal SPECT was performed in all (61). Ictal SPECT was localizing in 8 of 9 (88.8%). Interictal SPECT was localizing in a significantly higher proportion of patients (47.54%) than either the scalp EEG (16.39%) (P = .0003) or CT scan (21.56%) (P = .0046). Our data demonstrated that interictal and ictal SPECT identified more focal changes in children with intractable epilepsy than interictal EEG, CT, and probably MRI. The definitive proof of the SPECT-based findings being epileptogenic foci awaits correlation with intraoperative monitoring and postoperative follow-up.

Topics: Adolescent; Child; Child, Preschool; Diagnosis, Differential; Electroencephalography; Epilepsy; Female; Humans; Infant; Male; Preoperative Care; Radiopharmaceuticals; Sensitivity and Specificity; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed

Our aims were to identify (a) the characteristic magnetic resonance imaging (MRI) findings of cortical dyslamination with cytomegaly, including dysplastic and destructive lesions; (b) the relationship between MRI findings and pathologic characteristics; (c) the diagnostic role of functional neuroimaging studies in patients with these pathologies.. The series consisted of 23 adult patients who had proven cortical dyslamination with cytomegaly. The abnormalities found on MRI were subdivided according to the patterns of involvement. They also were compared with the patients' pathologic characteristics. With visual qualitative analysis, [18F]fluorodeoxyglucose with positron emission tomography (FDG-PET), and ictal single-photon emission computed tomography (SPECT), observations were classified as localizing, lateralizing, nonlateralizing, false-localizing, and false-lateralizing. The standard for correct localization of neuroimages was defined to be the resected lobe.. Focal abnormalities were found in 14 cases by MRI. Six cases showed typical MRI findings of focal cortical dysplasia, with focal areas of cortical thickening with or without poor grey-white matter differentiation. Focal subcortical high signal intensities on T2-weighted images occurred in two cases. Six patients had the focal destructive pattern. Three of eight cases with normal MRI and four of eight cases with the nondestructive cortical dysplasia pattern had balloon cells. However, these were not found in six patients with the destructive MRI pattern. FDG-PET localized the pathologic lobe in 13 (65%) of 20 cases, and ictal SPECT achieved this in 11 (61.1%) of 18 cases. FDG-PET and ictal SPECT also correctly localized the pathologic lobe in four and two cases with normal MRI, respectively.. Two distinct patterns of abnormal MRI were found in the pathology of cortical dyslamination with cytomegaly. These dysplastic and destructive patterns might reflect different pathogeneses, such as the time of insult. FDG-PET and ictal SPECT have confirmatory and independent diagnostic roles in localizing epileptogenic foci.

Topics: Adult; Cell Size; Cerebral Cortex; Epilepsies, Partial; Epilepsy; Female; Fluorodeoxyglucose F18; Humans; Magnetic Resonance Imaging; Male; Neurons; Technetium Tc 99m Exametazime; Tomography, Emission-Computed; Tomography, Emission-Computed, Single-Photon; Treatment Outcome

Peri-ictal single-photon emission tomography (SPET) difference images co-registered to magnetic resonance imaging (MRI) visualize regional cerebral blood flow (rCBF) changes and help localize the epileptogenic area in medically refractory epilepsy. Few reports have examined the reproducibility of SPET difference image results. Epilepsy patients having two peri-ictal and at least one interictal SPET scan who later underwent surgical resection were studied. Localization accuracy of peri-ictal SPET difference images results, interictal electroencephalography (EEG), and ictal EEG from the first (seizure 1) and second (seizure 2) seizure, as well as MRI and positron emission tomography (PET) findings, were compared using surgical resection site as the standard. Thirteen patients underwent surgical resection (11 temporal lobe and 2 extratemporal). SPET results from seizure 1 were localized to the surgical site in 12/13 (92%) patients, while SPET results from seizure 2 were localized in 13/13 (100%) patients. All other modalities were less accurate than the SPET results interictal EEG--seizure 1 6/13 (46%); ictal EEG--seizure 1 5/13 (38%); interictal intracranial EEG--seizure 2 4/9 (44%); ictal intracranial EEG--seizure 2 results 8/9 (89%); MRI 6/13 (46%); PET 9/13 (69%)[. SPET results were reproducible in 12/13 (92%) patients. SPET difference images calculated from two independent peri-ictal scans appear to be reproducible and accurately localize the epileptogenic area. While SPET difference images visualize many areas of rCBF change, the quantification of these results along with consideration of injection time improves the diagnostic interpretation of the results.

Topics: Adult; Brain; Cerebrovascular Circulation; Electroencephalography; Epilepsy; Female; Humans; Magnetic Resonance Imaging; Male; Radiopharmaceuticals; Reproducibility of Results; Technetium Tc 99m Exametazime; Tomography, Emission-Computed; Tomography, Emission-Computed, Single-Photon

To clarify the spatial and temporal distribution of the electroencephalographic (EEG) pattern termed 'periodic lateralized epileptiform discharges' (PLEDs), we performed magnetoencephalography (MEG) to analyze PLEDs in a patient with a right parietal metastasis associated with meningeal carcinomatosis.. A 37-channel biomagnetometer was used to simultaneously record the EEG and MEG. Equivalent current dipole (ECD) source localization was calculated based on a single-dipole model and mapped onto a magnetic resonance image. Single-photon emission computed tomography with technetium-99-hexamethyl-propyleneamine oxime (HMPAO-SPECT study) was also performed during both presence and absence of PLEDs according to an EEG monitor.. By EEG the PLEDs, predominantly right-sided, consisted of a typical negative triphasic spike followed by a slow negative wave. By MEG the PLEDs had a sequence with 3 distinct components. ECDs in the 3 components were localized to the cortex around the lesion, although exact localization and dipole direction varied between components. HMPAO-SPECT demonstrated hypoperfusion of the lesion and adjacent cortex during both quiescence and appearance of PLEDs.. Our results indicate that PLEDs originated from the hypoperfused cortex surrounding the lesion.

Topics: Brain Mapping; Cerebral Cortex; Epilepsy; Functional Laterality; Humans; Magnetic Resonance Imaging; Magnetoencephalography; Male; Middle Aged; Parietal Lobe; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

The basic aim of neuroimaging in children with intractable focal epilepsy is stablishing localization of epileptogenic zone. In this study 34 children (age 11-17 years) with intractable focal epilepsy were examined including: clinical history, physical examination, EEG, CT, MR, 99mTc-HMPAO SPECT. The hypoperfused region in interictal SPECT was concordant with clinical seizure characteristics in 22 children, with EEG in 13, with MR with 13 children. The localization of hyperperfused region in ictal SPECT was concordant with the clinical seizure characteristics in 9 from 10 examined children, with EEG in 7 and with MR in 8. The diagnostic value of estimation of the localization of epileptogenic zone in interictal SPECT (63 per cent) was comparable with the results of EEG (56 per cent) and MR (59 per cent), but ictal SPECT offers more information (100 per cent). In conclusion, performing both ictal and interictal SPECT studies may provide data about both seizure origin and its relationship with structurally abnormal regions of the brain.

Topics: Adolescent; Brain; Child; Electroencephalography; Epilepsy; Female; Humans; Magnetic Resonance Imaging; Male; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed

Increased regional cerebral blood flow (rCBF) at the epileptogenic site has been consistently reported for single photon emission computed tomography (SPECT) injections made during seizure activity, and the increased rCBF has been shown to remain elevated at the epileptogenic site in some cases, even when SPECT injections are made after seizure termination (postictal). A sustained increase in rCBF after seizure cessation was recently confirmed, but for no more than 100 s from seizure onset [Avery, R.A., Spencer, S.S., Spanaki, M.V., Corsi, M., Seibyl, J.P., Zubal, I.G., 1999. Effect of injection time on postictal SPET perfusion changes in medically refractory epilepsy. Eur. J. Nucl. Med. 26, 830-836]. In the current study, it is examined whether ictal SPECT injections demonstrate a similar change in rCBF around 100 s from seizure onset. Twenty-one patients with medically refractory epilepsy and a known area of seizure onset receiving ictal and interictal 99mTc-Hexamethyl-propyleneamineoxime (HMPAO) SPECT scans were studied. The results of SPECT subtraction analysis which visualize increased and decreased rCBF were compared to seizure duration and HMPAO injection time. Five patients received ictal SPECT injections (during ongoing seizure activity) more than 90 s after seizure onset and demonstrated decreased rCBF. Two of these patients also demonstrated areas of increased rCBF. Decreased rCBF was localized to the epileptogenic lobe in four of the five patients. By examining ictal SPECT injections made 90 s after seizure onset, evidence was found that reduced rCBF may exist during ictus. The change in rCBF around 90 s is also observed in postictal injections, suggesting a common metabolic mechanism may be responsible.

Topics: Adolescent; Adult; Cerebrovascular Circulation; Child; Epilepsy; Female; Humans; Middle Aged; Radiopharmaceuticals; Seizures; Technetium Tc 99m Exametazime; Time Factors; Tomography, Emission-Computed, Single-Photon

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

The mechanism by which vagal nerve stimulation (VNS) exerts an anticonvulsant effect in humans is unknown. This study used (99m)Tc-HMPAO single photon emission tomography (SPECT) to examine the effects of VNS on regional cerebral activity in thalamic and insular regions. Seven subjects with epilepsy who had been receiving vagal nerve stimulation for at least 6 months underwent SPECT scanning with simultaneous scalp electroencephalographic (EEG) recording. Subjects were studied in two states; during VNS activity and during a comparison condition of VNS inactivity. A region of interest analysis demonstrated that rapid cycling stimulation (7 seconds on, 12 seconds off) was associated with relatively decreased activity in left and right medial thalamic regions. No systematic stimulation-related changes were observed on visual or spectral analysis of EEG data. The thalamus is involved in modulation of ongoing cortical EEG activity in animals. Our results support the hypothesis that VNS may exert an antiepileptic action by an effect on thalamic activity.

Topics: Adult; Electric Stimulation Therapy; Electroencephalography; Epilepsy; Humans; Middle Aged; Radiopharmaceuticals; Statistics, Nonparametric; Technetium Tc 99m Exametazime; Thalamus; Tomography, Emission-Computed, Single-Photon; Vagus Nerve

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

Contrast enhancing single ring or disc lesion (CESRL), a frequent finding in the CT scan of Indian patients with seizures, has a diverse etiology. Underlying cause in many of these cases remains conjectural. Some of these ring lesions show spontaneous resolution without any specific treatment and in others their temporal profile remains unpredictable.. In a prospective study we studied 17 cases of epilepsy, with the CT scan finding of single contrast enhancing ring lesion. Detailed clinical evaluation and interictal EEG was performed. CT scan and SPECT study was done initially and were then repeated.. On the second CT, one lesion disappeared and 2 reduced in size, three showed no change in size. Third CT showed complete disappearance in one case and no change in the second case. Initial SPECT study was abnormal in all 17 cases, showing areas of hypoperfusion corresponding to the anatomical location of ring lesion. On follow up, patients with decreased ring size on CT showed decrease in area of perfusion deficit on the SPECT, but cases in which the lesion disappeared on the CT, the SPECT perfusion abnormality continued to persist, though to a lesser extent.. Persistence of perfusion defects suggest the presence of altered underlying physiology. Hence, early withdrawal of antiepileptic drugs after disappearance of ring lesion on CT may lead to seizure recurrence. SPECT studies repeated after 3 months may help to prognosticate cases with CESRL and also help in deciding the optimum duration of antiepileptic therapy in individual cases.

Topics: Adolescent; Adult; Brain; Child; Electroencephalography; Epilepsy; Female; Humans; Imaging, Three-Dimensional; Male; Middle Aged; Prospective Studies; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed

Five functions of merit were used for the registration of 99Tcm-HMPAO brain SPET studies. The correlation coefficient (COR), the stochastic sign change (SSC), the standard deviation of ratios (SDR), the sum of the absolute differences (SAD) and a new function based on a local correlation coefficient (LOC) were tested in the registration of photic neuroactivation (ACT), epilepsy (EPL) and Wada (WAD) SPET studies. The comparison included simulated and real studies. The translation error in registration was 0.1 +/- 0.1 pixels (mean +/- S.D.) for all functions of merit for the complete set of simulated studies (10 runs for each ACT, EPL and WAD). For rotation, LOC yielded the best results with a mean error of 0.3 +/- 0.2 degree and a maximum error of 0.6 degree. Slightly higher errors were found with SAD (0.4 +/- 0.2 degree, maximum 1.0 degree) and COR (0.5 +/- 1.0 degree, maximum 1.0 degree). The highest errors were found with SDR (0.8 +/- 1.0 degree, maximum 4.8 degrees) and SSC (0.8 +/- 1.1 degrees, maximum 4.7 degrees). The results obtained from five real studies of ACT, of EPL and of WAD were in agreement with the findings from the simulated studies, thus confirming the robustness of LOC, SAD and COR for the registration of 99Tcm-HMPAO brain SPET studies.

Topics: Algorithms; Brain; Epilepsy; Humans; Image Processing, Computer-Assisted; Photic Stimulation; Radiopharmaceuticals; Rotation; Stochastic Processes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Topics: Diagnostic Imaging; Electroencephalography; Epilepsy; Fluorodeoxyglucose F18; Hippocampus; Humans; Magnetic Resonance Imaging; Radiopharmaceuticals; Sensitivity and Specificity; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed; Tomography, Emission-Computed, Single-Photon

MR imaging, PET, and ictal SPECT have been studied extensively as individual techniques in the localization of epileptogenic foci, but only a few comparative studies have been done. We evaluated the concordance rates of ictal video/EEG, MR imaging, PET, and ictal SPECT to compare the sensitivities of these imaging methods in the lateralization of epileptogenic foci.. The study included 118 consecutive patients who underwent surgery for medically intractable epilepsy and who were followed up for 12 months or more. MR imaging was compared retrospectively with ictal video/EEG, FDG-PET, ictal 99mTc-HMPAO SPECT, and invasive EEG as to their ability to localize the epileptogenic focus; the pathologic findings served as the standard of reference.. MR imaging was concordant with video/EEG, PET, and ictal SPECT in 58%, 68%, and 58% of patients, respectively. With the pathologic diagnosis as the standard of reference, MR imaging, PET, and ictal SPECT correctly lateralized the lesion in 72%, 85%, and 73% of patients, respectively. Of the patients with good outcomes, MR imaging, PET, and ictal SPECT were correct in 77%, 86%, and 78%, respectively. In the good outcome group, MR imaging was concordant with PET and ictal SPECT in 73% and 62% of patients, respectively. Of 45 patients who underwent invasive EEG, MR imaging was concordant with the invasive study in 47%; PET in 58%; and ictal SPECT in 56%. Of 26 patients with normal MR findings, PET and ictal SPECT correctly lateralized the lesion in 80% and 55%, respectively.. Overall concordance among the techniques is approximately two thirds or less in lateralizing epileptogenic foci. PET is the most sensitive, even though it provides a broad approximate nature of the epileptogenic zone, which is not adequate for precise surgical localization of epilepsy. PET and/or ictal SPECT may be used as complementary tools in cases of inconclusive lateralization with ictal video/EEG and MR imaging.

Topics: Adolescent; Adult; Brain; Child; Electroencephalography; Epilepsy; Female; Fluorodeoxyglucose F18; Follow-Up Studies; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Radiopharmaceuticals; Retrospective Studies; Sensitivity and Specificity; Technetium Tc 99m Exametazime; Tomography, Emission-Computed; Tomography, Emission-Computed, Single-Photon; Treatment Outcome; Videotape 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

1. The IAP is used presurgically in patients with temporal lobe epilepsy to predict the effects on LTM and language of the planned temporal lobectomy. This prognosis presumes that a similar pattern of perfusion will result in anesthesia of the same cerebral regions in most patients. 2. Coinjection of Tc-99m HMPAO with the barbiturate during the IAP has been used to ascertain whether this actually is true, with variable results. Moreover, most studies document only unilateral IAPs and do not report on behavioral performance. 3. The authors coinjected Tc-99m HMPAO and amobarbital in 33 IAPs from 18 patients (15 injected bilaterally, 3 unilaterally) to clarify this and to evaluate the relationship of the perfusion pattern to behavioral performance; SPECT results were also compared to angiographic evaluation obtained at the time of catheter placement. 4. SPECT perfusion data was rated for presence/absence and intensity of perfusion to the ACA, MCA, PCA territories and to H, i or c to the injection site. V, STM and LTM were graded according to a standardized protocol. 5. MCAi was perfused in 100% of cases, ACAi in 91%, PCAi in 21% and Hi in only 6%. Cross-over flow was shown in 9 studies; 50% of the patients in whom both sides were injected (on different days) had crossover, involving the ACAc territory in 80% of cases. As expected, injection on the non-ES was associated with a significantly worse LTM performance than on the ES (p = 0.006). There was no relationship between the perfusion pattern and the V level of the patients (a potential confounding variable in memory/language evaluation) during IAP, nor between perfusion pattern and LTM. STM was significantly adversely affected by the presence of crossover perfusion. Angiography in general overestimated the extent of cerebral perfusion demonstrated by SPECT, most probably because of the markedly different injection conditions. 6. Despite the best efforts to standardize injections, the perfusion pattern has been mostly unpredictable in the patients. Moreover, it has little bearing on their behavioral performance, except for the prediction of poor STM performance (the clinical implications of this remaining dubious). Marked LTM alterations after non-ES injections confirm remote hippocampal effects in the presence of only rare direct perfusion of that region. Tc-99m HMPAO/Amobarbital coinjection was unhelpful from a clinical perspective, most probably because a large part of the effects of amobarbital arise fr

Topics: Adult; Amobarbital; Cerebral Angiography; Epilepsy; Female; Humans; Hypnotics and Sedatives; Language; Male; Memory; Predictive Value of Tests; Prognosis; Radionuclide Imaging; Technetium Tc 99m Exametazime; Temporal Lobe

Single-photon emission tomography (SPET) brain imaging in epilepsy has become an increasingly important noninvasive tool in localizing the epileptogenic site. Ictal SPET demonstrates the highest localization sensitivity as compared with postictal and interictal SPET. While ictal SPET consistently reveals hyperperfusion at the epileptogenic site, postictal SPET reveals either hyper- or hypoperfusion depending on the timing of radiopharmaceutical injection. Much discussion in the literature exists about exactly when the transition from hyper- to hypoperfusion occurs at the epileptogenic site in postictal SPET. The systematic examination of two clinical variables - time of injection from seizure onset and offset - was useful in understanding postictal perfusion changes. Twenty-seven patients with medically refractory epilepsy receiving postictal and interictal SPET scans were studied. Quantitative SPET difference imaging was used to evaluate perfusion changes in relationship to injection time. Perfusion changes were found to reflect the time of injection in relation to seizure onset, but to be somewhat independent of seizure offset. Thus, the majority of patients (8/12, 67%) receiving postictal injections within 100 s after seizure onset demonstrated hyperperfusion, while all patients (15/15, 100%) receiving postictal injections more than 100 s after seizure onset showed hypoperfusion. The explanation of this phenomenon is unknown but the findings appear to parallel known changes in cerebral lactate levels.

Topics: Adult; Brain; Cerebrovascular Circulation; Epilepsy; Female; Humans; Male; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Time Factors; Tomography, Emission-Computed, Single-Photon

Topics: Basal Ganglia; Brain; Cerebrovascular Circulation; Epilepsy; Female; Hemiplegia; Humans; Infant; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Thalamus; 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

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

Depression is a recognized feature of epilepsy. This study tested the hypothesis that depression arising in patients with epilepsy would be associated with decreased activity in brain regions previously demonstrated to be hypoperfused both in primary depression and in depression secondary to movement disorders. Two groups of patients with temporal lobe epilepsy were studied, one of which also met DSM IV criteria for a major depressive episode. All underwent a SPECT scan using the blood flow marker,(99m)Tc-HMPAO. An automated voxel-based analysis demonstrated no regions of relatively decreased activity in the depressed compared with the non-depressed patients. Sites of relative hyperactivity in the depressed group were concentrated in the left hemisphere, particularly in dorsolateral prefrontal cortex, striatum, thalamus and temporo-parietal regions. Comparison of these data with normal population data revealed that in the depressed epilepsy group regional activities were within the normal range whilst corresponding results from the non-depressed group were below it. Depressed patients with epilepsy have cerebral regions with greater perfusion than non-depressed people with epilepsy, although they are not hyperperfused compared with normals. Our results suggest that depression in people with epilepsy may arise from a mechanism which differs from that underlying the development of depression in patients with movement disorders.

Topics: Adult; Brain; Depressive Disorder, Major; Electroencephalography; Epilepsy; Female; Humans; Male; Movement Disorders; Psychiatric Status Rating Scales; Radiopharmaceuticals; Technetium Tc 99m Exametazime; 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: Basal Ganglia Diseases; Calcinosis; Child; Electroencephalography; Epilepsy; Female; Humans; Hypoparathyroidism; Magnetic Resonance Imaging; Technetium Tc 99m Exametazime; 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

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

The authors report 2 clinical cases that illustrate the difficulties with video-monitored EEG and the advantages of brain SPECT in differential diagnosis of true epileptic seizures and nonepileptic seizures. Injection of [99mTc]HMPAO at the time of the ictal event provides a means to obtain a SPECT image postictally for comparison with interictal examinations so that an epileptic or nonepileptic focus may be localized.

Topics: Adult; Cerebrovascular Circulation; Diagnosis, Differential; Electroencephalography; Epilepsy; Humans; Male; Organotechnetium Compounds; Oximes; Seizures; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Seizures with ictal laughter (also termed gelastic seizures) have been associated with hypothalamic hamartomas and precocious puberty. It is not known, however, where in the brain such seizures originate. We describe a child with gelastic seizures and a hypothalamic lesion (probably a hamartoma) in whom two dysfunctional phenomena were observed.. First, there was a hyperperfusion in the hypothalamopituitary areas shown by ictal [99m]Tc hexamethyl-propyleneamine oxime (HM-PAO) single photon-emission computed tomography (SPECT). Second, there was an ictal pulse of gonadotropins, 17 beta-estradiol, and growth hormone well above the normal limits in one of the seizures.. These findings suggest that gelastic seizures associated with hypothalamic hamartomas are generated in the hypothalamus or in its neighboring regions and that these seizures may cause paroxysmal dysfunction of the hypothalamopituitary axis.

Topics: Adolescent; Epilepsy; Female; Hamartoma; Humans; Hypothalamic Diseases; Hypothalamo-Hypophyseal System; Laughter; Organotechnetium Compounds; Oximes; Seizures; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Thirteen patients (mean age 8.4 + 5.3 years) with Rett syndrome (RS) were studied with EEG and 99mTc-HMPAO SPECT. Eleven patients had background abnormalities and 10 patients paroxysmal activity in EEG. Hypoperfusion of varying severity was detected in 11 patients, 7 patients having multiple lesions. Bifrontal hypoperfusion, observed in 6 patients, was the most distinctive finding. Hypoperfusion was observed also in other cortical regions, except for the occipital lobes. There was no correlation between severity of the background abnormality or presence of paroxysmal activity in EEG and grade of hypoperfusion. There was, however, an association between the severity of hypoperfusion and early manifestation of symptoms in patients with RS. Whether this early-onset group of patients represents a different disease entity or only reflects disease variability the basic pathology being the same, is a possibility that deserves further clarification.

Topics: Adolescent; Brain; Cerebrovascular Circulation; Child; Child, Preschool; Electroencephalography; Epilepsy; Female; Humans; Organotechnetium Compounds; Oximes; Rett Syndrome; Severity of Illness Index; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Topics: Brain; Cerebrovascular Circulation; Electroencephalography; Epilepsy; Humans; Infant, Newborn; Occipital Lobe; Organotechnetium Compounds; Oximes; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Patients with epileptic and nonepileptic seizures are commonly encountered in clinical practice, and they can pose a difficult diagnostic problem. We present two cases that show the difficult task of differentiating between true epileptic and nonepileptic or psychogenic seizures in some patients. The clinical presentations were complex and the use of video-monitored EEG alone was insufficient to make definitive diagnoses. Ictal and interictal Tc-99m HMPAO brain perfusion SPECT imaging examinations were used to help establish the correct diagnoses. This report describes the advantage of using the brain perfusion SPECT imaging examination. The injection of stabilized Tc-99m HMPAO during an ictal event followed by appropriate medical therapy provides a method of obtaining a reasonable image of relative perfusion (activity) during the seizure. These images can then be compared with interictal examinations and an epileptic or nonepileptic focus may be localized. The Tc-99m HMPAO brain perfusion SPECT imaging study was helpful in establishing the correct diagnosis in both cases.

Topics: Adult; Anticonvulsants; Brain; Cerebrovascular Circulation; Delta Rhythm; Depression; Diagnosis, Differential; Diazepam; Electroencephalography; Epilepsy; Epilepsy, Complex Partial; Female; Frontal Lobe; Humans; Image Enhancement; Organotechnetium Compounds; Oximes; Psychophysiologic Disorders; Radiopharmaceuticals; Seizures; Subtraction Technique; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon; Video Recording

Topics: Amnesia; Epilepsy; Humans; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Time Factors; Tomography, Emission-Computed, Single-Photon

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

99mTC (single photon emission computed tomography) (HMPAO SPECT) was carried out during 16 frontal-lobe seizures in 15 patients. Focal changes in regional cerebral blood flow were seen during all seizures. In 9 of 16 seizures SPECT showed hyperperfusion localized to one frontal lobe. In 1 of 16 seizures ictal hypoperfusion was seen in one frontal lobe. In 2 of 16 seizures there was hyperperfusion in both frontal lobes, and in 4 of 16 seizures hyperperfusion involved the frontal lobe or lobes plus other lobes of the brain. These changes were accompanied by hyperperfusion of subcortical structures in 13 seizures. SPECT thus localized to one frontal lobe in 10 of 16 seizures, and localized to the frontal lobes without lateralizing in two further seizures. No seizure showed a pattern of perfusion similar to that reported in mesial-temporal-lobe seizures. We conclude that ictal SPECT may provide useful localizing information in frontal-lobe seizures.

Topics: Adolescent; Adult; Basal Ganglia; Brain Stem; Cerebellum; Child; Electroencephalography; Epilepsy; Female; Frontal Lobe; Humans; Male; Regional Blood Flow; Technetium Tc 99m Exametazime; Thalamus; Tomography, Emission-Computed, Single-Photon

This study was performed to determine the utility of 99mTc-HMPAO brain SPECT in evaluating patients with pure photosensitive epilepsy.. Seven patients (2 boys, 5 girls), aged 8 to 15 yr (mean 11.1 +/- 2.5 yr), were studied. All patients underwent a detailed neurologic examination, interictal and ictal EEGs, CT and/or MRI and SPECT imaging. The baseline SPECT study was performed during the interictal period and the activation study was performed while the patients were having seizures provoked by watching television.. The baseline SPECT study showed that six of seven patients had relatively hypoperfused regions in their frontal lobes that could involve the neighboring parietal and temporal regions. The activation study revealed that all seven patients had relative hyperperfusion in these brain regions that were relatively hypoperfused in the baseline study. The side-to-side asymmetry indexes for these visually-interpreted rCBF abnormalities ranged from 3% to 6%.. The relatively consistent pattern of frontal rCBF alterations suggests that frontal lobe functions were implicated in the evolution of photosensitivity-related seizures in patients with pure photosensitive epilepsy.

Topics: Adolescent; Brain; Cerebrovascular Circulation; Child; Electroencephalography; Epilepsy; Female; Humans; Male; Organotechnetium Compounds; Oximes; Photic Stimulation; Technetium Tc 99m Exametazime; Television; Tomography, Emission-Computed, Single-Photon; Visual Perception

Several neuroimaging techniques that supplement electrophysiologic methods of evaluating pediatric patients with localization-related epilepsies before surgery assess both structural and functional abnormalities. For example, single photon emission computed tomography (SPECT) with technetium-99m-hexamethylpropyleneamine oxime (99mTc-HMPAO) has been used to demonstrate abnormal cerebral perfusion. States of cerebral perfusion during the interictal and immediate postictal periods have been reported to correlate with epileptiform foci identified by electroencephalogram (EEG). Between January 1987 and March 1993, we studied 55 pediatric patients with intractable seizures with prolonged video EEG telemetry in the epilepsy monitoring unit, followed by computed tomography, magnetic resonance imaging, and SPECT, before surgery to determine whether SPECT studies with 99mTc-HMPAO improved the accuracy of locating the epileptic focus. Interictal SPECT was performed on all patients, and immediate postictal SPECT (within 10 minutes after seizure ended) on 17 patients monitored in the epilepsy monitoring unit. In 15 (88%) of the 17, the combination of interictal and postictal SPECT studies yielded results corresponding to the EEG abnormality, a result significantly better than that obtained from interictal studies alone: 21 (55%) of 38 (chi 2 = 5.647, P = .0175). SPECT scans showed localized abnormal perfusion in the ipsilateral temporal lobe in all six patients with mesial temporal sclerosis, but precise results were not obtained in cases of dual pathology and neuronal migration disorders. Depiction of cerebral perfusion by interictal and immediate postictal SPECT studies can lead to greater accuracy in the localization of epileptic foci.

Topics: Adolescent; Brain Diseases; Brain Mapping; Child; Child, Preschool; Dominance, Cerebral; Electroencephalography; Epilepsy; Female; Humans; Male; Monitoring, Physiologic; Organotechnetium Compounds; Oximes; Regional Blood Flow; Retrospective Studies; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon; Video Recording

Twenty-five consecutive patients being considered for surgery for intractable epilepsy had intracarotid sodium methohexital procedures (ISM) as part of their evaluation. The lipophilic brain SPECT agent, [99mTc]hexamethylpropylene aminoxime (HMPAO), was administered intravenously during the procedure to determine the intracerebral distribution of methohexital. The validity of the ISM depends on consistent delivery of the anesthetizing agent to one hemisphere, including the mesial structures of the temporal lobe. To prevent postoperative language and memory deficits, correct interpretation of the test results supposes a reliable knowledge of which regions of the brain have been anesthetized. Currently, no absolute criteria allow determination of the level and topographical extent of the anesthesia. We compared results of HMPAO-SPECT with clinical and EEG video-monitoring data and with results of digital subtraction angiography (DSA) performed during the test. In all patients, the effect of SM was ipsilateral cerebral hypoperfusion on SPECT and crossed cerebellar diaschisis. The distribution of HMPAO varied from patient to patient. The delivery of SM to mesial temporal lobe structures was not constant. Using nonparametric tests, we demonstrated a statistically significant relationship between hypoperfusion on SPECT and duration of hemiplegia but not with the duration of aphasia. Hypoperfusion on SPECT was also related to the onset and duration of drug-induced delta activity on EEG. SPECT showed a statistically different distribution of SM in the brain from that predicted with DSA. We present our experience with HMPAO-SPECT use for mapping the distribution of methohexital's effects during the ISM (Wada test). We confirm the results of previous studies that SPECT assessment may be an excellent way of determining the distribution of barbiturate during the examination. It increases confidence in interpreting results of speech and memory testing by detecting either contralateral diffusion of the drug due to crossflow between hemispheres or insufficient quantitative delivery to the homolateral hemisphere.

Topics: Adult; Brain; Cerebral Angiography; Electroencephalography; Epilepsy; Female; Functional Laterality; Humans; Male; Methohexital; Middle Aged; Monitoring, Physiologic; Organotechnetium Compounds; Oximes; Subtraction Technique; Technetium Tc 99m Exametazime; Tissue Distribution; Tomography, Emission-Computed, Single-Photon; Videotape Recording

A case of absence of the left internal carotid artery with epilepsy was reported. Only a few cases of absence of the internal carotid artery with epilepsy in childhood have been reported in Japan. A flow void image of the cavernous sinus portion of the left internal carotid artery was not obtained on MRI. MR angiography and digital subtraction angiography also did not reveal the left internal carotid artery. On thin slice, axial CT scanning of the skull base, the right carotid canal was normally observed, but the left carotid canal was hypoplastic. It was suggested that the epileptic focus was in the right hemisphere, judging from the fast waves dominant over the right hemisphere on ictal EEG, and the hyperfusion in the right parietal and occipital lobes seen on 99mTc-HMPAO SPECT one hour after the seizure.

Topics: Angiography, Digital Subtraction; Carotid Artery, Internal; Child, Preschool; Contrast Media; Epilepsy; Female; Humans; Magnetic Resonance Angiography; Magnetic Resonance Imaging; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed

Reading epilepsy is rare. We report a 14-year-old right-handed Japanese boy who had had jaw jerking only while reading since age 12 years. The episodes occurred every time he read an English textbook and sometimes during prolonged reading of a Japanese textbook. The jaw jerking evolved to generalized tonic-clonic seizures (GTCS) on only two occasions during prolonged reading aloud. Routine EEGs showed no abnormality. After a few minutes of reading, however, the EEG showed bilateral 2-Hz, 150-microV spike-wave complexes with left frontotemporal accentuation, accompanied by jaw jerking. Ictal single photon emission computed tomography (SPECT) with [99Tc]hexamethylpropylene amine oxime (HMPAO) showed focal hyperperfusion of the frontal lobes bilaterally and of the left temporal area. Interictal SPECT and magnetic resonance imaging (MRI) were normal. The combination of valproate (VPA) and clonazepam (CZP) almost eliminated his symptoms. Ictal SPECT is a useful technique for seizure localization in reading epilepsy.

Topics: Adolescent; Cerebral Cortex; Electroencephalography; Epilepsy; Humans; Male; Organotechnetium Compounds; Oximes; Reading; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Accurate localization of epileptic foci is important for pre-surgical evaluation of patients with medically intractable epilepsy, and F-18 FDG PET has been proved to be a valuable method for this purpose. To examine the clinical value with interictal brain perfusion SPECT, we performed brain perfusion SPECT of Tc-99m HMPAO by means of a high resolution SPECT camera, and compared the results with F-18 FDG PET images and MRI in 10 patients with medically intractable epilepsy. In 9 of 10 patients (90%), FDG PET images showed focal hypo-metabolism in the area corresponding with the results of electroencephalography (EEG). SPECT images, however, demonstrated hypo-perfused lesions which corresponded with hypo-metabolic lesions on FDG PET images in only 6 cases (60%). Although MRI showed abnormal findings in 8 cases, the lesions were not directly related to epileptic foci in 2 cases. In conclusion, FDG PET is a valuable tool for accurate localization of epileptic foci. Brain perfusion SPECT, however, may not always be paralleled to metabolism visualized on FDG PET images.

Topics: Adolescent; Adult; Deoxyglucose; Epilepsy; Female; Fluorodeoxyglucose F18; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Organotechnetium Compounds; Oximes; Radiography; Technetium Tc 99m Exametazime; Tomography, Emission-Computed; Tomography, Emission-Computed, Single-Photon

With recent descriptions of the modified hemispherectomies and hemicorticectomy, there has been renewed interest in hemispherectomy for treatment of intractable seizures with hemiparesis. Because long-term outcome remains uncertain, patient selection remains difficult. 99mTc-HmPAO brain SPECT has been a helpful adjunct in the evaluation of epilepsy surgery candidates. We report SPECT scan findings in 7 patients who underwent hemispherectomy and compare these results with scalp EEG findings. Six patients had unilateral SPECT findings and all had a favorable outcome, regardless of surface EEG findings.

Topics: Adolescent; Cerebral Cortex; Cerebral Decortication; Child; Child, Preschool; Dominance, Cerebral; Electroencephalography; Epilepsy; Female; Follow-Up Studies; Hemiplegia; Humans; Infant; Male; Monitoring, Physiologic; Organotechnetium Compounds; Oximes; Postoperative Complications; Regional Blood Flow; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

To better identify regions of the brain affected by intracarotid amobarbital injections and to more precisely predict whether resections of specific brain regions will cause postoperative memory deficits.. We modified the standard intracarotid amobarbital procedure by adding a radioactive tracer to the amobarbital injection, thereby providing better correlation between behavior and deactivated brain region.. Tertiary-care hospital center with a dedicated program for medical and surgical treatment of epilepsy.. We studied 39 patients with medically intractable epilepsy drawn from a regional referral base.. Intracarotid injection of 125 mg of sodium amobarbital with 37 MBq of technetium Tc 99m hexamethylpropyleneamine oxime (HMPAO), followed by language and memory testing.. The distribution of amobarbital as measured by single photon emission computed tomographic imaging of HMPAO and patient performance on memory tasks.. Medial temporal regions were irrigated by the amobarbital in only 28% of the injections. Overall, findings suggest that medial temporal and lateral neotemporal cortex play a role in memory.. The regions involved in memory function vary by individual, as does the distribution of amobarbital. Thus, the most accurate method of determining correlation of brain region with memory function during intracarotid amobarbital injection involves the use of a tracer such as HMPAO.

Topics: Adolescent; Adult; Amobarbital; Brain; Carotid Arteries; Cerebrovascular Circulation; Epilepsy; Female; Humans; Injections; Male; Memory Disorders; Middle Aged; Organotechnetium Compounds; Oximes; Postoperative Complications; Radionuclide Imaging; Technetium Tc 99m Exametazime; Temporal Lobe

NeuroSPECT of regional cerebral blood flow (rCBF) with Tc-99m HMPAO demonstrated left temporoparietal hyperemia in two patients with acute receptive aphasia. This finding prompted further testing with electroencephalography that added to the impression of ictal dysphasia. The differential diagnosis in one case included complicated migraine. NeuroSPECT depicts blood flow abnormalities in acute aphasic disorders, either due to ischemia, which is most commonly the cause, or due to hyperemia secondary to migraine or epilepsy. The treatment and prognosis of these latter conditions differ from stroke, and thus SPECT plays a role in patient management.

Topics: Adult; Aphasia, Wernicke; Cerebrovascular Circulation; Diagnosis, Differential; Epilepsy; Female; Humans; Hyperemia; MELAS Syndrome; Middle Aged; Organotechnetium Compounds; Oximes; Parietal Lobe; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon

Assessment of cerebral perfusion may elucidate pathogenesis of Landau-Kleffner syndrome (LKS). We obtained 99mTc-HMPAO SPECT studies in five children with LKS and in three children with syndromes of verbal-auditory agnosia. In LKS, perfusion showed temporoparietal asymmetry (9.56% +/- 3.44%) (n = 4) or bilateral parietal abnormality (n = 1). SPECT in non-LKS patients was normal (n = 1), showed (n = 1) totihemispheral hypoperfusion accompanying structural abnormality or (n = 1) a pattern resembling but distinct from LKS. Seizures in LKS patients had never occurred (n = 1), were controlled satisfactorily (n = 2), or poorly (n = 2). Maximum EEG abnormality was left centrotemoral-occipital (n = 1), left frontocentral (n = 1), bitemporal/left central (n = 1), and left central/parasagittal (n = 1). Asymmetric temporoparietal perfusion appears characteristic of LKS, differing from findings in other childhood linguistic disturbances. This abnormality occurs across a spectrum of seizure expression, diverging from the distribution of EEG abnormalities. The SPECT abnormalities parallel PET-defined LKS metabolic abnormalities, and may indicate central pathogenetic features of the disorder.

Topics: Aphasia; Apraxias; Brain; Child; Child, Preschool; Electroencephalography; Epilepsy; Female; Humans; Image Processing, Computer-Assisted; Male; Organotechnetium Compounds; Oximes; Syndrome; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon

Changes of brain images in single photon emission CTs (SPECTs) before and after intravenous injection of bemegride were examined with simultaneous EEG recording in a patient with occipital lobe epilepsy and in a hysteric patient, using a new method, i.e. subtraction of the SPECT images with 99mTc hexamethyl-propyleneamine oxime. The bemegride injection in the epileptic patient paradoxically intensified the hypoperfusion images as epileptic foci in SPECTs, associated with enhanced interictal epileptic discharges, whereas the hysteric showed no such effects. These findings suggest that the hypoperfusion images closely correlate to the severity of epileptic activity, reflecting a functional rather than a morphological deficit.

Topics: Adult; Bemegride; Cerebral Cortex; Electroencephalography; Epilepsy; Humans; Male; Occipital Lobe; Organotechnetium Compounds; Oximes; Reference Values; Regional Blood Flow; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Single photon emission tomography (SPECT) using Tc-99m-d,1-hexamethylpropylenamine oxime (HMPAO) was performed in two children with epileptic disorders during both sleeping and waking diurnal stages. Immediate postictal and interictal SPECT scans were obtained for a child with partial epilepsy. They demonstrated an interictal decrease in the regional cerebral blood flow (rCBF) and a more remarkable immediately postictal decrease in rCBF. The focus was in the same region of the SPECT for both interictal and postictal spikes. Another patient was diagnosed as having continuous spike-waves during slow sleep without epileptic seizures. Although SPECT during wakefulness showed no asymmetry, SPECT during sleep revealed decreased rCBF at the same location as the predominant area of diffuse epileptic discharges. We conclude that HMPAO SPECT is useful in investigation of the etiological mechanisms of seizures and epileptic discharges in epileptic disorders in childhood.

Topics: Age Factors; Brain; Cerebrovascular Circulation; Child; Epilepsy; Female; Humans; Male; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

The regional cerebral blood flows (rCBF) in 45 cases of epilepsy during the interictal period were determined with brain SPECT. The results were compared those obtained with CT scans and EEG. 48.89% of the SPECT were found to be abnormal while 8.98% were suspected to be abnormal; the 35.71% of the CT scans were found to be abnormal; 16 cases (39.02%) were found to show focal abnormalities in the EEG while 9 cases (21.95%) had epileptic form discharge. SPECT seemed to show more significance in discovering the abnormalities in the epileptics during the interictal period than CT or EEG. However, the combined use of these three methods of examinations would be of greater help for identifying the focal abnormalities in epilepsy. Two of the 22 cases with abnormal SPECT had increased rCBF, whereas the other 20 cases had decreased rCBF. Among the 22 cases of abnormal SPECT and 4 cases of suspected abnormalities, the locations of the lesions as indicated with SPECT in 3 cases were not consistent with those as with CT. There were 5 cases in which the SPECT findings were not consistent with those in EEG.

Topics: Brain; Cerebrovascular Circulation; Electroencephalography; Epilepsy; Humans; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed

Imaging findings of morphology and regional cerebral blood flow in two patients suffering from epileptic seizures are presented. CT and MRI revealed heterotopic gray matter as a probable structural correlate, causing the seizure disorder. 99mTc hexamethyl-propylenamine oxime (HM-PAO) SPECT demonstrated focally increased regional cerebral blood flow in both patients in the areas of their heterotopic lesions. Heterotopic and orthotopic gray matter seem to have similar features in terms of regional perfusion. A focally increased brain perfusion in interictal epileptic patients may indicate an underlying migration anomaly.

Topics: Adult; Brain Neoplasms; Cerebrovascular Circulation; Choristoma; Epilepsy; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Thirteen mentally retarded pediatric patients aged 4 to 13 years with therapy-resistant epilepsy underwent Tc-99m HMPAO brain perfusion SPECT studies. The results (abnormal in 12 of the 13 patients) were compared with EEG results in 12 of the 13 patients (abnormal in all 12) and x-ray CT in 11 of the 13 patients (normal in 9). Patients with spikes on EEG had foci of increased uptake on HMPAO. This study confirms that HMPAO is sensitive in detecting perfusion abnormalities and localizing epileptic foci in this group of patients.

Topics: Brain; Cerebrovascular Circulation; Child; Electroencephalography; Epilepsy; Female; Humans; Intellectual Disability; Male; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed

A convection-diffusion model is applied for the determination of cerebral circulation parameters in patients with frontal lobe epilepsy. The method employs 99mTc-HMPAO, dynamic brain imaging and SPECT. The model takes into account both the capillary and cell permeabilities of HMPAO. Experiments were performed in 41 patients with epilepsy and 10 patients without evident cerebrovascular disease. The results indicate that in the inter ictal epileptic foci, cerebral blood flow was reduced (18% +/- 19%), cerebral blood volume was increased (21% +/- 14%), and the capillary permeability of HMPAO in the affected side was on the average 50% of the value in the contralateral side, whereas the reflux from brain tissue to blood was increased. These findings mean that HMPAO diffusion across the blood brain barrier is restricted and HMPAO slackly interacts with the intra cellular component of the inter ictal epileptic foci.

Topics: Adult; Capillary Permeability; Cerebrovascular Circulation; Epilepsy; Frontal Lobe; Humans; Models, Theoretical; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

A patient is described who developed complex partial seizures with secondary generalization 3 years after a severe viral encephalitis with a CT and EEG identified lesion in the left insular cortex and its surrounding structures. When the seizures first occurred CT and MRI as well as repeated interictal conventional EEG recordings were entirely normal. Single photon emission computed tomography (SPECT), however, revealed an area of increased 99mTc-hexamethyl propyleneamine oxime (HMPAO) uptake in the left insular cortex. After anticonvulsive therapy the seizures and the SPECT findings disappeared. 99mTc-HMPAO SPECT is a highly sensitive method for the demonstration of functional alterations in brain tissue. It can improve diagnosis of epilepsy and may provide additional information to monitor anticonvulsive therapy.

Topics: Adult; Anticonvulsants; Epilepsy; Female; Humans; Organometallic Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

Effective surgical treatment of patients with intractable complex partial seizures depends on accurate preoperative seizure focus localization. We evaluated seizure localization with interictal and immediate postictal single photon emission computed tomographic images of cerebral perfusion using technetium-99m-hexamethyl-propyleneamineoxime (99mTc-HMPAO) in comparison with conventional ictal electroencephalographic (EEG) localization. Thirty-two patients with intractable complex partial seizures were studied. The mean delay from seizure onset to injection was 6.3 +/- 5.3 (SD) minutes. Independent blinded observers assessed the scans for interictal hypoperfusion and postictal focal hyperperfusion. Interictal scans alone were unreliable, indicating the correct localization in 17 patients (53%) and an incorrect site in 3 (9%). When interictal and postictal scans were interpreted together, the focus was correctly localized in 23 patients (72%). There was 1 false-positive study, and 8 patients had inconclusive changes, including 2 with inconclusive depth EEG studies. Postictal hyperperfusion was predominantly mesial temporal and frequently associated with hypoperfusion of lateral temporal cortex. Secondarily generalized seizures tended to show focal hyperperfusion less often than complex partial seizures did (Fisher's exact test p = 0.09). Combined interictal and immediate postictal single photon emission computed tomography with 99mTc-HMPAO is a useful noninvasive technique for independent confirmation of electrographic seizure localization. It may provide a suitable alternative to the use of depth electrode studies for confirmation of surface EEG findings in many patients with complex partial seizures.

Topics: Adolescent; Adult; Electroencephalography; Epilepsy; Female; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Temporal Lobe; 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

Twenty-eight normal volunteers and 74 seizure patients were investigated with hexa-methyl-propylene-amine-oxime (HMPAO) brain single photon emission computed tomography (SPECT). Fifty-four patients suffered from partial seizures and 20 patients had generalized seizures. Indices describing regional tracer distribution (RIs) were calculated in all investigated subjects. Regions whose RI exceeded the mean normal RI +/- 3 SD were defined as abnormally perfused. In normals a significant interhemispheric asymmetry of HMPAO deposition was found, with higher RI values in the right frontal, parietal, temporal and occipital regions. In 59.3% of partial seizure patients abnormal RIs were found. Low RIs were detected predominantly in the frontal and temporal cortex, while elevated RIs were observed predominantly in the anterior basal ganglia. Only in 20% of the cases with generalized seizures, abnormal RIs were found. In one patient an ictal and 3 follow-up SPECT studies were obtained. Here SPECT results indicated transient rCBF changes between the ictal and seizure free state. EEG and SPECT foci were ipsilaterally located in 69.2% of the partial seizure cases. The results indicate that HMPAO brain SPECT is valuable for the detection of rCBF abnormalities in seizure patients and that patients with partial seizures have mostly several abnormally perfused areas in their brains.

Topics: Adult; Brain; Cerebrovascular Circulation; Electroencephalography; Epilepsies, Partial; Epilepsy; Humans; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

In nine patients with suspected psychogenic seizures and in three patients with proven epileptic seizures HMPAO-SPECT was performed prior to and during seizure. In the patients with later on-proven psychogenic seizures no, or only slight, changes of regional cerebral blood flow were found. Patients with proven epilepsy revealed partly normal findings interictally but during seizure a markedly increased circumscript blood flow was found in all patients. Even though PET is superior to SPECT with respect to spatial resolution, in the diagnosis of seizures HMPAO-SPECT has the advantage of enabling injection of the tracer during the seizure and the performance of the SPECT study subsequently.

Topics: Epilepsy; Humans; Organometallic Compounds; Oximes; Seizures; Technetium; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

Topics: Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Epilepsy; Humans; Organometallic Compounds; Oximes; Sodium Pertechnetate Tc 99m; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

Technetium-99m hexamethylpropyleneamineoxime ([99mTc]HM-PAO) brain single photon emission computed tomography (SPECT) was performed with a dual head rotating scintillation camera. Normal tracer distribution and side/side differences of counting rates were obtained in 11 healthy volunteers. Almost stable gray/white matter ratios were found (1.97-2.1) in one normal subject during 2 hr after tracer administration. Eighty-three investigated patients had the following diagnoses (in parentheses is percent of positive findings in each group): cerebral vascular disease 18 (94.4%), epilepsy 23 (82.6%), extrapyramidal disorders 8 (100%), dementia 12 (100%), headache 11 (63.6%), psychiatric disorders 11 (27.3%). In addition, SPECT was performed in 28 male volunteers during motor or visual imagery tasks and a significant increase (p = 0.035) of relative tracer deposition was observed in the left inferior occipital region during visual imagery when compared with motor imagery. The results indicate that [99mTc]HM-PAO SPECT is valuable for demonstrating pathologic and physiologic changes of the brain.

Topics: Adult; Aged; Basal Ganglia Diseases; Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Dementia; Epilepsy; Female; Headache; Humans; Imagination; Male; Mental Disorders; Middle Aged; Organometallic Compounds; Oximes; Technetium; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

The lipophilic brain SPECT agent [99mTc]hexamethyl propylene amine oxime (HM-PAO) was used in three cases before and during unilateral anesthesia of one hemisphere for lateralization of speech dominance (Wada test). This procedure led to a decrease of regional cerebral blood flow (rCBF) in each of the hemispheres to 55 and 90%, respectively. Diminution of rCBF was significantly more pronounced in the dominant hemisphere. A second phenomenon observed during the Wada test was crossed cerebellar diaschisis. These findings support the assumption that HM-PAO allows monitoring of brain perfusion, as rapid changes of rCBF due to decreased neuronal activity cause respective alterations of cerebral and cerebellar uptake of this new brain agent.

Topics: Adolescent; Adult; Brain; Cerebrovascular Circulation; Dominance, Cerebral; Epilepsy; Female; Humans; Male; Organometallic Compounds; Oximes; Technetium; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

Topics: Brain; Epilepsy; Humans; Organometallic Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

Topics: Adult; Brain; Brain Diseases; Cerebrovascular Disorders; Epilepsy; Female; Headache; Humans; Middle Aged; Organometallic Compounds; Oximes; Reference Values; Technetium Tc 99m Exametazime; Tomography, Emission-Computed

After having outlined the importance of evaluating, in cerebral diseases, the regional cerebral blood flow by means of a non invasive method, the advantages of SPECT with Tc99m HM-PAO compared to the SPECT with radioxenon and iodoamphetamine are point out. The results obtained with this method on 28 different patients, six of with were normal subjects, while the remaining 22 were suffering: six from cerebro vascular disease, four from epilepsy, three from TIA, six from dementia, two from depressive syndrome and one from hemicrania are reported. The comparison of the results with literature references, proves that the tracer employed is definitely superior to TCT, while there is a coincidence with SPECT data obtained with radioxenon and iodoamphetamine. The radiotracer employed can be successfully used, due to its convenient physical-chemical features, in a daily routine, for the evaluation of regional cerebral blood flow in encephalic diagnostics.

Topics: Adult; Aged; Brain Diseases; Cerebrovascular Disorders; Dementia; Depressive Disorder; Diagnosis, Differential; Epilepsy; Evaluation Studies as Topic; Humans; Middle Aged; Oximes; Reference Values; Technetium; Technetium Tc 99m Exametazime; Tomography, Emission-Computed