Quantitative analysis of 123I-iomazenil single-photon emission computed tomography findings from patients with infantile epileptic spasm syndrome.

Abstract

Purpose: This study aimed to elucidate the distribution of intracranial gamma-aminobutyric acid (GABA) receptors in patients with infantile epileptic spasms syndrome (IESS) of normal brain MRI findings using ¹²³I-iomazenil single-photon emission computed tomography (IMZ-SPECT).

Methods: This retrospective study compared IMZ-SPECT images from 20 patients with IESS of unknown etiology with normal brain MRI (unknown IESS group) and 23 patients with developmentally normal epilepsy of the same age (developmentally normal group). A three-dimensional stereotactic region of interest (ROI) template was used to divide the brain into 24 segments (left and right callosomarginal, precentral, central, parietal, angular, temporal, posterior cerebral, pericallosal, lenticular nucleus, thalamus, hippocampus, and cerebellum), and the mean accumulation of ¹²³I-iomazenil in each ROI was calculated. The IMZ ratio for each ROI was calculated by dividing the ROI count by the mean cerebellar count of the left and right sides for the same patient. IMZ ratios for 22 ROIs, excluding the cerebellum, between the unknown IESS group and the developmentally normal group were compared.

Results: No significant differences were observed between the background characteristics of the unknown and developmentally normal groups. Hypsarrhythmia were observed in 16 patients in the IESS group. The IMZ ratio showed no significant differences between the two groups across all 22 ROIs.

Conclusion: The IMZ ratio of the unknown IESS group was not significantly different from that of the developmentally normal group across the 22 ROIs, suggesting that GABA receptor distribution has little effect on epileptic spasms and hypsarrhythmia, and vice versa.