3-DIMENSIONAL SPIRAL CT ANGIOGRAPHY IN THE DETECTION OF CEREBRAL ANEURYSM

Purpose. The value of CT angiography in the detection and evaluation o f aneurysms was compared to digital subtraction angiography (DSA). Mat erial and Methods. Seventeen patients with acute subarachnoid hemorrha ge (SAH) or with known or suspected aneurysm were investigated by mean s of spiral CT angiography, which included 3D reconstruction. These fi ndings were compared with those at DSA. Results. In 16 patients, 20 an eurysms were found; the remaining patient had an ectatic vessel that s imulated an aneurysm. Seventeen of the angiographically proved aneurys ms were detected at CT angiography (sensitivity 85%). One further aneu rysm was identified retrospectively as the result of greater experienc e in the method. All the aneurysms that escaped detection at CT were 3 mm in size. All the vessels of the circle of Willis, except for the p osterior communicating artery, were properly evaluated at CT angiograp hy. Difficulties were encountered in assessing the posterior communica ting artery and the extradural segment of the internal carotid artery owing to their close spatial relationship to the bony structures of th e skull base and the cavernous sinus. Conclusion. CT angiography is a low-risk technique with a low level of invasiveness that is useful in following up known aneurysms. The 3D reconstruction yields further top ographic information that helps in the planning of endovascular or sur gical intervention. The facility for rotating the reconstructed vessel s and displaying them from different angles is of particular value in cases difficult to assess at angiography.