Figure 1.

Sidewall aneurysm measurements. Patient (male, 46 years) was hospitalized because of acute headache for one day. Head CT showed subarachnoid hemorrhage. Two days later 2 aneurysms in each carotid were found on digital subtraction angiography. The left carotid aneurysm is shown: maximal diameter (Dmax), longest dimension from the center of the neck to the dome tip (Hmax or height), maximal longitudinal diameter parallel with the neck plane (Wortho), dome width perpendicular to height (Wmax), the angle between axis of flow in the parent vessel at the level of the aneurysm neck and the aneurysm’s main axis from the center of the neck to the tip of the dome (inflow angle). The average value of both sides of the aneurysm neck=D1+D2/2 (average parent artery diameter).