Cerebral hemodynamics were studied in 38 children with “Moyamoya” disease. About 10mCi of Tc-99m was injected into the anterior cubital vein as a bolus, and serial brain scintigrams in one second intervals were obtained with a gamma scintilation camera (Ohio-nuclear Σ410s) and processed on an on-line radioisotope processing system including microcomputers (DEC PDP 11/34, 11/60).
The characteristic images of serial brain scintigraphy were obtained in preoperative cases: early accumulation of radioisotope activities in the base of the skull, corresponding to the basal “Moyamoya” vessels, and the poor filling in the territories of the anterior (ACA) and middle cerebral arteries (MCA), indicating disturbance of the cerebral circulation. After bypass surgery, early accumulation of RI activities in the base of the skull diminished and evidence of improved cerebral circulation in the territories of the middle cerebral artery was obtained, but poor filling in the territories of the anterior cerebral artery persisted, measurements of local mode of transit time (MOTT) were made by our modified method which was originally reported by Oldendorf. Regions of interest were bilaterally settled both in the areas of basal “Moyamoya” vessels and in the territories of MCA in the anterior view image. The mean values of MOTT in the MCA territories were significantly longer than in the basal “Moyamoya” (10.8±2.7 sec, 7.7±2.1 sec, N=17, respectively). After surgery, shortening of MOTT in the MCA territory was observed (5.8± 1.3 sec, N=17).
Positive static brain scintigrams were observed in only two cases. One patient was the case of cerebral infarction 14 days after the onset, the other patient showed a transient positive area in the region of the frontal lobe without neurological deficit, which was thought to be hyperpermeability of unknown origin. Findings of static brain scintigraphy of “Moyamoya” disease only indicated the results of damage of the blood-brain barrier.
From this evidence, it was concluded that dynamic studies using Tc-99m and a scinti-camera were useful not only in the diagnosis of “Moyamoya” disease, but also in the study of the pathophysiology of brain circulation.
