未破裂小脳動脈瘤の診断におけるthree-dimensional MR angiographyの有用性

We describe the utility of three-dimensional (3-D) magnetic resonance (MR) angiography in the detection of small unruptured cerebral aneurysms (SUCA). Seventy-six patients with suspected or detected unruptured cerebral aneurysms smaller than 10 mm by maximum intensity projection images using 3-D time-of-flight MR angiography were investigated by surface rendered 3-D MR angiography. About 10 minutes were required to reconstruct 3-D display images from source images of MR angiography. A total of 88 SUCA in 76 patients were detected on 3-D MR angiography. A majority of aneurysms were located at the anterior part of the circle of Willis, and the maximum diameter of the aneurysms ranged from 1.7 to 9.8 mm with a mean of 4.0 mm. 3-D MR angiography provided important information regarding the configuration of the aneurysm sac, its size, and its relationship to the surrounding vessels. These results indicate that 3-D MR angiography will make a contribution as a new supporting method in the detection of patients with SUCA.