[A study of collateral circulation in acute stage of occlusion of the middle cerebral artery].
Collateral circulation of angiogram in occlusion of main trunk of the middle cerebral artery in acute stage was studied in detail, and compared with the extent of the low density area on CT. Territory of the middle cerebral artery in the lateral view of angiogram was divided into three regions. Collateral circulation time was measured with the period from the maximum filling of carotid siphon to the retrograde maximum filling of collateral circulation. With these studies, the following conclusions were obtained. 1) The degree of collateral circulation is classified into three types. One type with good collateral circulation is type I. Another type with moderate collateral circulation is type II. A further type with poor collateral circulation is type III. Angiographic circulation time in each branch of the middle cerebral artery is measured in each type. 2) There is a tendency that types with the better development of collateral circulation have the smaller low density area on CT. In type I, the smallest low density area on CT appears in the territory of basal ganglia or around corona radiata. In type II or III, the medium or large low density area on CT appears in cortical and/or subcortical territory of the middle cerebral artery. 3) There is a tendency that types with the worse development of collateral circulation have the later collateral circulation time in each region. If collateral circulation time is later than 4 seconds, it is impossible to avoid the appearance of the low density area on CT in C region. In the same way, in B region, it is later than 5 or 6 seconds, in A region, it is later than 7 seconds. But, in type II or III, there are a few cases in which it is impossible to avoid the appearance of the low density area on CT, even if collateral circulation time is earlier than those mentioned. As mentioned above, classifying of collateral circulation is possible to expect the extent of the low density area on CT, and measurement of collateral circulation time is able to estimate the appearance of the low density area on CT. In type I and II, superficial temporal artery to middle cerebral artery anastomosis is apt to make the low density area narrow on CT, and to prevent the appearance of hemorrhagic infarction.
Yabuta
A
A
Department of Neurosurgery, Iwate Medical University, Japan.
D000208:Acute Disease; D000368:Aged; D002560:Cerebrovascular Circulation; D003097:Collateral Circulation; D005260:Female; D006801:Humans; D002542:Intracranial Embolism and Thrombosis / Q000473:pathology / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged