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Role of I‐123‐Iomazenil SPECT imaging in drug resistant epilepsy with complex partial seizures
Author(s) -
Sjöholm H.,
Rosén I.,
Elmqvist D.
Publication year - 1995
Publication title -
acta neurologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.967
H-Index - 95
eISSN - 1600-0404
pISSN - 0001-6314
DOI - 10.1111/j.1600-0404.1995.tb00464.x
Subject(s) - epilepsy , medicine , neuroscience , complex partial seizures , psychology , psychiatry , temporal lobe
Fifteen patients with therapy resistant partial complex seizures with no structural lesions were examined interictally with 123‐I‐IOMAZENIL SPECT for measurement of benzodiazepine receptor distribution and with 99m‐Tc‐HMPAO SPECT for measurement of cerebral blood flow distribution. Regional abnormalities were correlated with the seizure onset patterns in EEG later recorded with implanted subdural strips. SPECT scans were made immediately after and at 1 and 2 h after intravenous injection of 123‐I‐Iomazenil. During that time there was a continuous change from an immediate flow‐related distribution toward a more specific receptor distribution. The decay of radioactivity of I‐123 in the brain was linear over time. Two patients on benzodiazepine treatment showed much faster elimination and showed no focal abnormalities. Eight patients with clear‐cut unifocal seizure onset showed concordant focal benzodiazepine defects. These patients showed a progressive focus/homotopic non‐focus enhancement over time much larger than the HMPAO scans in the same patients. Also the estimated focal area of abnormality was more restricted in the Iomazenil scans than in HMPAO scans. Five patients had more complex seizure onset patterns. In these patients a mismatch between the locations of abnormalities in Iomazenil and HMPAO scans were often found but benzodiazepine receptor abnormalities were more circumscribed also in these patients. The results suggest that 123‐I‐Iomazenil SPECT is more useful than 99m‐Tc‐HMPAO SPECT when applied interictally in patients with partial complex epilepsy, since in addition to demonstrate the hemispheric laterality of the epileptogenic zone, 123‐I‐Iomazenil appears to indicate its anatomical location with higher confidence, which could be of practical value for positioning of intracranial EEG electrodes.