Computed tomography in 'Moyamoya' disease

Fifty patients were studied by computerized tomography (CT). The results were as follows: 1. Low-density areas (LDA) in the cortex and subcortical white matter were observed in 70% of the children and 55% of the adult patients. In the children, LDA's with a moss-eaten appearance were often observed bilaterally, while in adults they were seen over an extensive region corresponding to the cerebral arterial supply area. The LDA's was seen in basal ganglia in 3 cases, in all of which they were single, small, circular lesions. A ventricular enlargement was seen in 40% of the children and 28% of the adults. Among the 35 cases in which enhancement studies were done, an increased attenuation value after enhancement was noted at the cerebral cortex in 13 cases and at the basal ganglia in 6 cases. 2. LDA's were not seen in any of the TIA cases (symptoms disappeared within 24 hours), while some LDA's were observed in all the other stroke cases. 3. The CT scans obtained at the onset of the ''Moyamoya'' disease showed enhancement at the ischemic cerebrovascular lesions. In the TIA cases, the enhanced lesions disappeared as time passed. In the stroke cases, the initially enhanced lesions changed to LDA. In the cases of a slowly progressing stroke, however, no evidence of contrast enhancement was seen, but small LDA's gradually grew larger. 4. The CT scans obtained after ST-MC anastomosis showed contrast enhancement at the dura mater of the operated area in every case. It became most conspicious in 2 -- 3 weeks and disappeared in 4 -- 6 weeks postoperatively. Among the cases who suffered from TIA and RIND (symptoms disappeared within 3 weeks) after operation, 4 cases showed enhanced lesions in the cortical and sub-cortical regions. They became more prominent 1 -- 2 weeks after the operation and then disappeared within 4 weeks. (J.P.N.)