Fig 2.

A 71-year-old woman with subarachnoid hemorrhage.

A, Left anterior oblique projection volume-rendered MDCTA image shows a saccular aneurysm arising from the anterior communicating artery (arrow). The neck of aneurysm was graded as wide (grade 3; N/D ratio, >2/3) by both readers on the basis of volume-rendered images.

B, DSA image of the left internal carotid artery, obtained in a projection similar to that of the DSA image shown in A, shows the narrow (grade 1; N/D ratio, <1/3) neck of the aneurysm (arrow).