[Usefulness of thin axial images of computerized tomography angiography for surgery on paraclinoidal carotid artery aneurysms].

A number of surgical experiences with paraclinoidal carotid artery aneurysms have been reported recently. However, neuroradiological examinations can not sufficiently visualize the topographic relations around the aneurysms due to variations in the size of the anterior clinoid process (ACP) or course of the carotid artery in individual cases. Although three-dimensional computerized tomography angiography (3-D-CT-A) is known to be useful for the surgical management of cerebral aneurysms in common locations, its usefulness for paraclinoidal carotid artery aneurysms has not been investigated. Ten cases involving a total of 13 aneurysms located in the clinoid portion of the carotid artery were included in this study according to Al-Radham's classification (Table). The CT scan used was an X Force system manufactured by Toshiba Electric Co, Japan. Non-ionic, iodinated contrast solution, a total of 2ml/kg, was intravenously infused at a rate of 2ml/sec. Helical scanning was begun 30 seconds after initiating the infusion, 1mm pitch/1.5 second/rotation. 3-D images and original images of axial slices were compared to conventional angiography, DSA and surgical findings. The 3-D images of 3-D-CT-A was able to demonstrate both aneurysms located in the C2 segment of the carotid artery (groups I and II), and five of nine carotid cave aneurysms (group III). The aneurysms located more proximally (group IV or V) could not be visualized.(ABSTRACT TRUNCATED AT 250 WORDS)