[Angiographic analysis of the middle cerebral artery in cerebral aneurysms--its branching pattern and so-called vascular anomalies].

UNLABELLED

Branching patterns of middle cerebral artery (MCA) were angiographically analyzed in 704 cases with cerebral aneurysms. The mean age was 53 years old and the men-to-women ratio was 1.1. In addition, 13 vascular anomalies of MCA were reported and their correlation with the occurrence of cerebral aneurysm was studied.

RESULTS

MCA branching patterns were classified in 6 types. Each type was further studied by dividing into 2 subgroups, namely one with MCA aneurysms at their side and the other without MCA aneurysms. There were no differences statistically between each two groups. Vascular anomalies were consisted of 5 duplications of MCA, 4 fenestrations, 3 accessories and one case of combination of duplication and accessory in the same side. Duplications and accessories did not have any evidence of developing aneurysm more frequently at their bifurcation than any one of normal MCA branching patterns. So we concluded that duplications and accessories should be thought to have similar meanings with the ordinary branching patterns of MCA in the occurrence of aneurysms. A postmortem case of accessory MCA without aneurysm revealed that the origin of the anomaly was pathologically normal. We suggested that the origin of accessory MCA could both be an enlarged Heubner artery and a rare branching pattern of MCA. The fenestration should be a true anomaly but at this point we do not have any suggestive clue for that. Finally, we thought that the combination of duplication and accessory in a single MCA was very rare morphologically, and worthwhile to report.