123I-iomazenil: a quantitative study of the central benzodiazepine receptor distribution

Fourteen patients with temporal lobe epilepsy, 9 patients after amygdalohippocampectomy and 3 healthy volunteers were examined with the new benzodiazepine receptor marker 123I-Iomazenil and SPECT. For comparison perfusion SPECT studies with 99mTc-HMPAO were done and a quantitative ROI analysis of the data performed. This quantitative analysis consisted of calculation of right-to-left ratios for 123I-Iomazenil SPECTs, whereby values of 1 were obtained with narrow standard deviations. ROI measurements of the medial occipital, frontal and parietal cortex, the cerebellum and white matter showed a pattern of benzodiazepine receptor concentration in concordance with that previously found in PET and autoradiographic studies, if 123I-Iomazenil ROIs were normalized to the corresponding 99mTc-HMPAO ROIs. The abnormal distribution in the temporal lobes will not be discussed in this paper.