The recent development of a new radiopharmaceutical 123 I-isopropyl-p-iodoamphetamine (IMP), which is taken up by the brain from the blood flow, has offered a possibility of constructing scintigraphy maps of regional cerebral blood flow (rCBF) using single photon emission CT. We evaluated the clinical utility of this method in moyamoya disease.
Five patients with moyamoya disease, who were examined by IMP-SPECT before and after bypass operations, were selected. On the IMP images before operations, all patients showed focal or global decrease of rCBF. There was a good correlation between the area and degree of rCBF abnormalities and severity of clinical symptoms and stage on angiography. The area of rCBF decrease coincided with the dominant area of rebuild-up phenomena on EEG. On the IMP images just after operations, the rCBF changed for the worse transiently in three patients, and the crossed cerebellar diaschisis appeared in two patients. On the IMP images 3 months after operations, the rCBF increased in company with the improvement of clinical symptoms. The increased rCBF on the point of operation was recognized in two patients with good prognosis.
These results suggest that IMP-SPECT is a noninvasive and useful method of assessing the effects of therapy as well as the characteristic hemodynamic abnormalities in moyamoya disease.