ソナグラフ表示による超音波血流検査法の臨床的応用—脳循環を中心として

ANALYSIS OF ULTRASONIC BLOOD-RHEOGRAPH WITH SONAGRAPH FOR CLINICAL APPLICATION

I．まえがき

　近年高年者人口の増加に伴い精神神経科領域においても老年期精神障害の比重はしだいに高まりつつある。このなかでも脳循環障害と一次的に，ないしは二次的に関係のあるものの数はかなりのものであると推測される。

　脳循環動態を生理的な条件下に客観化し，それを治療と結びつけようとする努力は数多くの人によつてなされてきた。1945年にKety　＆　Schmidtにより人の脳循環測定がN₂O法によりなされて以来最近のアイソトープによる測定方法にいたるまで過去20年間脳循環動態をいかに正確に，いかに生理的かつ動的にとらえるかということが一つの課題であつた。しかしこれが一般臨床検査として応用されるには，技術的に複雑でありすぎてはその利用価値は，たとえ結果が正確であるとしても減じることになる。

Technique of Ultrasonic Blood-Rheograph was im-proved by the introduction of the analysis with Sona-graph in our laboratory for the accurate and quantita-tive examination of the circulatory blood flow. The outline of the fundamental reseach of this method was described, and observation of the changes with aging, posture and the effects of vasodilators on cerebral homodynamics were reported.

1) In the common and internal carotid arteries, the circulatory blood flows of the aged group suspected to cerebral arteriosclerosis were significantly de-creased as compared with those of young normals. The change was remarkable in both primary sys-tolic phase (Si) and diastolic phase (D, d).

2) By changing the posture from supine to sitting, a marked decrease in the circulatory flow of the ex-ternal carotid was observed, while changes of blood flow were scanty in the internal carotid and ver-tebral flows. Two cases showing a decrease of vertebral flow were with basilar insufficiency.

3) For the purpose of examining the influence of vasodilators to the cerebral circulation, isoxsuprine and cyclandelate were used. The possibility of different mechanism was discussed, while they were pharmacologically seemed to be the similar vaso-relaxant drugs.

Ten minutes later after the intramuscular injec-tion of 5 mg of isoxsuprine, the common, internal and external carotid flows were rather decreased with the falling of blood pressure in brachial artery. But 5 minutes after administration of 10 mg of isoxsuprine, the flows were increased and reached the maximal level after 10~20 minutes, and its effect lated for about an hour.

By intravenous injection of 112.5 mg of cyclan-delate, the common and external carotid flows were increased immediately with the falling of blood pressure, but they returned to the original level after 5 minutes. Change in the internal carotid flow was not significant.