[Junctional dilatation of the posterior communicating artery (author's transl)]

Junctional dilatation of the posterior communicating artery was investigated on 1,286 carotid angiograms, which were displayed to 750 patients for recent five years in our department, and the following results were obtained. 1) Incidence; The junctional dilatation was seen on 96 out of 750 cases (12.8%), whereas on angiograms, this was 105 times out of 1,286 angiograms. A difference in ratio of appearance between men and women was not statistically significant. 2) Comparison between the left and right side; 58 cases of junctional dilatation was seen out of 633 cases (9.2%) on the left side, and 47 out of 653 cases (7.2%) on the right side respectively. Bilataral junctional dilatations were seen only 9 out of 536 cases. There was no difference in appearance of the junctional dilatation on either side. 3) Relationship to age; There was a very few cases of junctional dilatation under the age of 20, while it rapidly increased in 3 to 4 decades. The incidence of junctional dilatation was seen in 32 out of 329 patients (9.7%) under 40 years of age, which was 6.7% of angiograms, on the other hand the incidence increased to 15.2% (64/421) over 40 years of age, which was 9.3% of angiograms (p less than 0.05). 4) The incidence of visualization of posterior communicating artery and posterior cerebral artery relation to junctional dilatation. We divided cases into the following 3 groups. (a) Type I: Visualization of partial or whole length of the posterior communicating artery (76.2%). (b) Type II: Visualization of the proximal portion of the posterior cerebral artery (18.1%). (c) Type III: Visualization of whole length of the posterior cerebral artery (5.7%). 5) Shape and size of junctional dilatation: The shape of dilatation could be divided into a funnel shape and a round shape. The funnel shape was seen in 32 cases (30.5%) and the round shape was seen in 73 cases (69.5%). Also the most of cases was larger than 2 mm in diameter.