Perfusion patterns in postictal 99mTc-HMPAO SPECT after coregistration with MRI in patients with mesial temporal lobe epilepsy

• Published in: Journal of neurology, neurosurgery and psychiatry neurosurgery and psychiatry, 1997-08, Vol.63 (2), p.235-239
• Main Authors: Hogan, R Edward, Cook, Mark J, Binns, David W, Desmond, Patricia M, Kilpatrick, Christine J, Murrie, Vanessa L, Morris, Kevin F
• Format: Article
• Language: English
• Subjects: Amygdala - blood supply; Amygdala - diagnostic imaging; Asymmetry; Biological and medical sciences; cerebral blood flow; Cerebrovascular Circulation; Convulsions & seizures; Electroencephalography; Epilepsy; Epilepsy, Temporal Lobe - diagnostic imaging; Epilepsy, Temporal Lobe - pathology; Headache. Facial pains. Syncopes. Epilepsia. Intracranial hypertension. Brain oedema. Cerebral palsy; Hippocampus - blood supply; Hippocampus - diagnostic imaging; Humans; Magnetic Resonance Imaging; Medical sciences; mesial temporal sclerosis; Nervous system (semeiology, syndromes); Neurology; Organotechnetium Compounds; Oximes; Patients; SPECT; Surgery; Technetium Tc 99m Exametazime; temporal lobe epilepsy; Tomography, Emission-Computed, Single-Photon; Tropical medicine; Work stations
• ISSN: 0022-3050; 1468-330X
• DOI: 10.1136/jnnp.63.2.235

OBJECTIVES To assess patterns of postictal cerebral blood flow in the mesial temporal lobe by coregistration of postictal 99mTc-HMPAO SPECT with MRI in patients with confirmed mesial temporal lobe epilepsy. METHODS Ten postictal and interictal99mTc-HMPAO SPECT scans were coregistered with MRI in 10 patients with confirmed mesial temporal lobe epilepsy. Volumetric tracings of the hippocampus and amygdala from the MRI were superimposed on the postictal and interictal SPECT. Asymmetries in hippocampal and amygdala SPECT signal were then calculated using the equation: % Asymmetry =100 × (right − left) / (right + left)/2. RESULTS In the postictal studies, quantitative measurements of amygdala SPECT intensities were greatest on the side of seizure onset in all cases, with an average % asymmetry of 11.1, range 5.2-21.9. Hippocampal intensities were greatest on the side of seizure onset in six studies, with an average % asymmetry of 9.6, range 4.7-12.0. In four scans the hippocampal intensities were less on the side of seizure onset, with an average % asymmetry of 10.2, range 5.7-15.5. There was no localising quantitative pattern in interictal studies. CONCLUSIONS Postictal SPECT shows distinctive perfusion patterns when coregistered with MRI, which assist in lateralisation of temporal lobe seizures. Hyperperfusion in the region of the amygdala is more consistently lateralising than hyperperfusion in the region of the hippocampus in postictal studies.