Usefulness of Multislice Computerized Tomographic Angiography in Evaluation of Intracranial Aneurysms: Surgical Correlation

ABSTRACT

OBJECTIVE: The usefulness of multislice computerized tomographic angiography(MCTA) in operating intracranial aneurysms is studied by comparing the features of MCTA with intraoperative findings. METHODS: From December 2001 to February 2003, 74 clippings of aneurysmal neck were carried out based mainly on the aneurysmal features of preoperative MCTA. MCTA studies consisted of four rows(multislice technology), with slice thickness of 1.25mm at 0.6mm reconstruction intervals and pitch of 0.75. Timing was determined using the Smart Prep automatic triggering system. The locations of aneurysms were classified into 3 subgroups internal carotid artery, middle cerebral artery, and anterior communicating artery and distal anterior cerebral artery. The aneurysmal features on MCTA were compared with their operative findings, using our comparison items, and graded subsequently. RESULTS: A total of 77 intracranial aneurysms were identified among 64 patients on preoperative MCTA, and one of them was false positive. Two angiographically unrecognized microaneurysms were identified on operation. In the detection of intracranial aneurysm, MCTA had 98.4% sensitivity and 96.9% specificity on a perpatient basis. On a per-aneurysm basis, MCTA sensitivity and specificity were 98.6% and 97.3%, respectively. The shapes of aneurysms on MCTA were not related with the grade(chi-square test X2=1.566, p=0.457), but each grades of simple, bilobulation, and multilobulation were grade 1. Sum of grading scores were related with site of aneurysm(Chi-square test X2=48.635, p=0.001), In particular, sum of grading scores of MCA aneurysms were 5. Although fine vascular architectures such as hypoplastic A1 and posterior communicating artery, perforating artery of A-COM, and anterior choroidal artery were invisible on MCTA, the MCTA images of ICA and A-COM aneurysms were also found to be valuable in intracranial aneurysm surgery. CONCLUSION: MCTA is useful in planning the surgery of intracranial aneurysm compared to single detector CTA. Postoperative DSA of stabilized patient is mandatory for confirming operative results and any missing unruptured aneurysm after MCTA based cerebral aneurysm surgery.