Moyamoya病の脳血管biplane CT像

BIPLANE COMPUTED CEREBRAL ANGIOTOMOGRAPHY OF MOYAMOYA DISEASE

I．はじめに

　脳血管撮影でみられるMoyamoya病の特異な血管像—すなわち，内頸動脈，前・中大脳動脈近位部の狭窄ないし閉塞像および脳底部の異常血管網—は，脳血管撮影から期待されるのに反し，CTでは描出され難いといわれていた^4,6,10,12）。

　一方，われわれは，これまで，高分解能CTを用いて，脳血管をCT画像上に鮮明に描出するための撮影方法に関する基礎的検討を行い，その結果を臨床応用してきた（脳血管CT，computed cerebral angiotomogra—phy^1,3））が，今回Moyamoya病症例においても，この脳血管CTを行うことにより，従来，CTでは描出され難いとされていた本症の特異な異常血管像をCT画像上に描出することができた。

In this paper, the authors report biplane computed cerebral angiotomographic findings in 5 cases of Moyamoya disease.

The specific features of Moyamoya disease on the CT image were as follows: On the axial plane, the linear structures of the anterior half of the circle of Willis and the proximal portion of the middle cerebral arteries disappeared, and instead of these nor-mal structures, irregular, tortuous or patchy high-density areas just like a"caterpillar"were shown in the basal cistern and medial Sylvian fissures. On the modified coronal plane, the supraclinoid internal carotid arteries and the carotid fork could be iden-tified only with a difficulty, and abnormal,"nebular" high-density areas consisting of irregular, tortuous or patchy high-density vascular components became visible in the basal cistern extending to the basal ganglia.

A modified coronal plane and intravenous mini-mum dose bolus injection method seemed to be more useful for the visualization of these specific features on the CT image.

Even before carotid angiography, we can suspect Moyamoya disease for finding these specific features on the CT image.

Carotid angiography has been the only method of diagnosing Moyamoya disease. Instead of this invasive examination, computed cerebral angiotomo-graphy is useful in detecting Moyamoya disease conveniently and non-invasively.

Therefore, we may conclude that computed cere-bral angiotomography is a very useful method for screening and follow up study of Moyamoya disease.