technetium-tc-99m-exametazime and Epilepsy--Tonic-Clonic

Regions of seizure onset and propagation in human generalized tonic-clonic seizures are not well understood. Cerebral blood flow (CBF) measurements with single photon emission computed tomography (SPECT) during electroconvulsive therapy (ECT)-induced seizures provide a unique opportunity to investigate seizure onset and propagation under controlled conditions.. ECT stimulation induces a typical generalized tonic-clonic seizure, resembling spontaneous generalized seizures in both clinical and electroencephalogram (EEG) manifestations. Patients were divided into two groups based on timing of ictal (during seizure) SPECT tracer injections: 0 s after ECT stimulation (early group), and 30 s after ECT (late group). Statistical parametric mapping (SPM) was used to determine regions of significant CBF changes between ictal and interictal scans on a voxel-by-voxel basis.. In the early injection group, we saw increases near the regions of the bitemporal stimulating electrodes as well as some thalamic and basal ganglia activation. With late injections, we observed increases mainly in the parietal and occipital lobes, regions that were quiescent 30 s prior. Significant decreases occurred only at the later injection time, and these were localized to the bilateral cingulate gyrus and left dorsolateral frontal cortex.. Activations in distinct regions at the two time points, as well as sparing of intermediary brain structures, suggest that ECT-induced seizures propagate from the site of initiation to other specific brain regions. Further work will be needed to determine if this propagation occurs through cortical-cortical or cortico-thalamo-cortical networks. A better understanding of seizure propagation mechanisms may lead to improved treatments aimed at preventing seizure generalization.

Topics: Brain Mapping; Cerebral Cortex; Cerebrovascular Circulation; Depressive Disorder; Depressive Disorder, Major; Electric Stimulation; Electroconvulsive Therapy; Electroencephalography; Epilepsy, Generalized; Epilepsy, Tonic-Clonic; Functional Laterality; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Technetium Tc 99m Exametazime; Thalamus; Tomography, Emission-Computed, Single-Photon

Four hours after having taken 10 ecstasy tablets a Grand Mal seizure occurred in a 19-year-old woman followed by coma, hyperthermia, tachycardia, tachypnea, and renal failure. After awakening she was oriented but presented with helplessness, disconcertion, hallucinations, panic attacks, and amnesic syndrome. Computed tomography and magnetic resonance imaging scans of the brain were normal. [99Tc]-hexamethylpropyleneamine oxime (HMPAO)-single photon emission computed tomography (SPECT), 20 days after intoxication, showed reduced, inhomogeneous, supratentorial tracer uptake bilaterally. Electroencephalography (EEG) disclosed diffuse slowing and occasionally generalized sharp waves. Valproic acid was begun. Except for slight amnesia, neuropsychological deficits had disappeared and [99Tc]-HMPAO-SPECT normalized, 29 days later. Decreased cortical blood flow was explained by vasoconstriction following ecstasy-induced depletion of serotonin.

Topics: Adult; Brain Ischemia; Cerebral Cortex; Coma; Dominance, Cerebral; Drug Overdose; Electroencephalography; Epilepsy, Tonic-Clonic; Female; Follow-Up Studies; Humans; N-Methyl-3,4-methylenedioxyamphetamine; Neuropsychological Tests; Regional Blood Flow; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Vasoconstriction

We report a 20-year-old male with epilepsy, mild mental retardation, growth asymmetry, and MRI and SPECT features of unilateral subcortical ectopic cortex. The neurological examination showed mild growth asymmetry, hemiparesis and hemihypoesthesia and pyramidal signs on the left side. EEG showed focal abnormality in the right frontotemporal region. MRI revealed pachygyria and severe heterotopia associated with some abnormalities of ventricles and cerebellum on the right. Cortical responses were absent on stimulation of the left median and tibial nerves. Central motor conduction time from cortex to left upper extremity was prolonged in magnetic stimulation test. SPECT using 99 mTc-HMPAO revealed increased perfusion of the right subcortical region as compared with those of overlying cortical mantle and opposite hemisphere. To our knowledge, there has been no report documenting such a large and extensive subcortical ectopic cortex which appears as a mass distorting and shifting the middle structure in an adult, such as in our case.

Topics: Adult; Brain; Cell Movement; Choristoma; Electroencephalography; Epilepsy, Tonic-Clonic; Evoked Potentials, Somatosensory; Humans; Magnetic Resonance Imaging; Male; Median Nerve; Neurons; Radiopharmaceuticals; Severity of Illness Index; Technetium Tc 99m Exametazime; Tibial Nerve; Tomography, Emission-Computed, Single-Photon

CT scan in a 52-year-old woman, admitted because of grand mal seizure, showed striopallidodentate calcifications due to postoperative hypoparathyroidism. This patient report stresses the possibility of cortical metabolic involvement in this disorder, as shown on Tc-99m HMPAO brain SPECT, despite the absence of cognitive defects.

Topics: Brain; Brain Diseases; Calcinosis; Epilepsy, Tonic-Clonic; Female; Humans; Hypoparathyroidism; Middle Aged; Organotechnetium Compounds; Oximes; Postoperative Complications; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon