[Preoperative evaluation of the aneurismal wall by using high-resolution MRI: report of 3 cases].

Surgical treatment of large cerebral aneurysms may depend on preoperative information regarding the wall thickness and the intraaneurysmal thrombosis. When the neck of an aneurysm is thick due to atherosclerosis or there is a marked thrombosis inside the aneurysm, clipping may not be possible. Here we report three cases with large internal carotid artery aneurysms that were evaluated for the thickness of the aneurysm wall and the presence of thrombosis by 3 tesla magnetic resonance (MR) imaging. A high-resolution T2-weighted imaging (HRT2WI) modified for 3 tesla was used. In two cases, the images showed the thickened wall of the dome to some extent which apparently did not reach the neck. These aneurysms were successfully neck clipped. The third patient showed marked thickening of the wall, which may be associated with thrombosis, which extended to the neck. Intraoperative findings of the aneurysm wall were compatible with these factors, and removal of atherosclerotic plaque and thrombus from the neck and dome of the aneurysm was necessary before successful neck clipping. The HRT2WI may contribute to a better surgical strategy for large aneurysms which may have wall thickening.