Moyamoya病の脳循環

CEREBRAL BLOOD FLOW IN MOYAMOYA DISEASE

　抄録　Moyamoya病の脳循環を半球血流量および局所脳血流分布から検討した。対象は，神経症状のほとんどない5歳から15歳までの小児moyamoya病21例および成人moyamoya病19例である。脳循環の測定は急性期をさけて行ない，¹³³Xe静注法により行ない，正常小児16例および成人14例を対照として比較検討した。小児moyamoya病においては脳血管写上のstageとの関係についても検討した。Moya-moya病の脳循環は成人高齢者を除き各年齢において正常例の脳循環に比し有意に低値を示した。局所脳血流分布は，いずれの年齢においても，正常の前頭優位の血流分布を示さず，後頭優位の分布を示した。小児moyamoya病においては，脳血管写上のstageの進行にともなって，半球血流量は減少する傾向を認めた。正常の前頭優位の血流分布はstageの進行とともに後頭優位のpatternへと連続的に変化し，この後頭優位な局所脳循環分布はmoyamoya病に特徴的であると考えられた。

Regional cerebral blood flow in forty cases of moyamoya disease was investigated by intravenous ¹³³Xe injection method. Twenty-one cases were children and other nineteen were adults. No or only slight neurological deficit were found at the CBF studies. CBF was calculated by initial slope index.

For investigation of the relation between hemi-spheric blood flow and age, the regression curve was calculated and that with highest correlation was chosen. In normal group, the relationship between hemispheric CBF and age was correlated to following equation: y=146.5-58.4 log x (r= -0.903). In contrast, in moyamoya disease, it was correlated to following equation: log y=2.04-0.23 logx (r=-0.730). It can be said that CBF of the whole brain in moyamoya disease is below normal.

The distribution of the rCBF was characteristic in moyamoya disease. There are low CBF values in the frontal and temporal lobes and relatively high values in the occipital lobes as compared with normal CBF distribution. These results are thought to indicate the importance of blood circu-lation to the brain from the vertebro-basilar arte-rial system.

Moreover a comparison of these CBF results with the six stages of basal moyamoya seen angio-graphically was investigated in child cases. As the stage of moyamoya disease progressed, the hemispheric CBF decreased gradually and the dist-ribution of blood flow gradually changed from a predominance of flow to the frontal lobes to a predominance of flow to the occipital lobes.