Evaluation of neuronal loss in adult moyamoya disease by I-123-iomazenil SPECT

BACKGROUND Central benzodiazepine (BZD) receptor imaging is effective to evaluate neur on density in the pathological brain cortex. This study used BZD receptor i maging to evaluate neuronal damage in adult ischemic moyamoya disease. METHODS Single photon emission computed tomography and a novel tracer, I-123-iomaze nil, were used to measure BZD receptor density in the brain. Evaluation of early and late images was performed in three asymptomatic, unoperated patie nts, and six mildly symptomatic, operated patients. RESULTS Uptakes in the frontal, parietal, and occipital lobes of symptomatic patien ts were significantly lower (p < 0.05) than those of asymptomatic patients. The late image/early image count ratios (L/E ratios) of asymptomatic patie nts were relatively constant (mean, 0.571; range, 0.550-0.581) in all regio ns of interest. In contrast, the L/E ratios of symptomatic patients were no t uniform. CONCLUSIONS The neuron density was preserved in adult asymptomatic patients despite har boring moyamoya disease. In contrast, the neuronal density was decreased in symptomatic patients even though their symptoms were mild and they had und ergone revascularization. (C) 1999 by Elsevier Science Inc.