Angiographic Study on Infundibular Dilatation of the Posterior Communicating Artery

Abstract

It is still debatable, whether the infundibular dilatation of the posterior communicating artery (ID) is preaneurysmal or not. Since there have been reports of aneurysms having developed clinically from ID, a proper follow-up or therapy procedures must be considered. In order to know what kind of cases must be followed up and operated on, incidence of ID was investigated on angiograms of 260 patients with cerebral aneurysms over the past 9 years. A statistical analysis of incidence and morphology of ID was performed. The results were as follows: 1) ID was seen in 67 out of 398 carotid angiograms (17%). This is about twice as much as in similar past studies on general neurological cases. 2) In patients with an internal carotid-posterior communicating artery aneurysm, the incidence of ID was much higher (P<0.05), and the ratio of round and large ID's was high (P<0.05). 3) Small ID's were mainly triangular in shape and large ID's chiefly round (P<0.01). 4) In young patients the ratio of large ID's was high (P<0.05). 5) In patients with a past history of hypertension, the ratio of large ID's was high (P<0.05). 6) In cases which had a well-developed posterior communicating artery, the ratio of round and large ID's was high (P<0.01). 7) In cases with a wide angle between the internal carotid artery and posterior communicating artery, the ratio of round and large ID's was high (P<0.05). Follow-up and therapy are indicated in cases with the above factors.