EVALUATION OF LARGE INTRACRANIAL ANEURYSM WITH 3-DIMENSIONAL MRI

Objective: The purpose of this study was to evaluate large intracrania l aneurysms by contrast-enhanced 3D MRI. Materials and Methods: Eleven patients, nine women and two men, were examined. The aneurysms involv ed the internal carotid artery in seven patients, the middle cerebral artery in one, the basilar artery in two, and the posterior cerebral a rtery in one. Contrast-enhanced 3D MR images were obtained using FLASH (fast low angle shot) on a 1.5 T system. We obtained axial images fir st, then sagittal and coronal images by multiplanar reconstruction. Th ose images were reviewed for comparison with conventional and MR angio graphy. Results: We could easily evaluate the true aneurysmal size, th e intraaneurysmal constitution (patent lumen and intraluminal thrombus ), and the detailed relationship of the aneurysm to the surrounding va scular and neural structures. Except for the cavernous internal caroti d artery, we could identify the aneurysmal neck by carefully observing axial, sagittal, and coronal images. In addition, the progression of intraaneurysmal thrombosis and the patency of the parent arterial lume n after the endovascular treatment were well appreciated. Conclusion: We consider that 3D MRI appears to be useful for evaluation of the lar ge intracranial aneurysm.