Role of Multislice Computerized Tomographic Angiography after Clip Placement in Aneurysm Patients Based on Comparison with Three Dimensional Digital Subtraction Angiography

OBJECTIVE: We evaluated the accuracy of multislice computerized tomographic angiography (MCTA) in the postoperative evaluation of clipped aneurysms by comparising it with three dimensional digital subtraction angiography (3D-DSA). METHODS: Between May 2004 and September 2006, we included patients with ruptured cerebral aneurysm of the anterior circulation that was surgically clipped and evaluated by both postoperative MCTA and postoperative 3D-DSA. We measured the diagnostic performance and calculated the sensitivity and specificity of postoperative MCTA compared to 3D-DSA in the detection of aneurysm remnants. RESULTS: A total of 11 neck remnants among the 92 clipped aneurysms (11.9%) were confirmed by 3D-DSA. According to Sindou's classification of aneurysm remnants, 8.7% of clipped aneurysms (8/92) had only neck remnant on 3D-DSA and 3.2% (3/92 aneurysms) had residuum of the neck and sac on 3D-DSA. There were 12 (13.04%) equivocal cases that were difficult to interpret based on the postoperative MCTA. The reasons for the equivocal cases included multiple clips (6 cases, 50.0%), beam-hardening effect (4 cases, 33.3%), motion artifact (1 case, 8.3%), fenestrated clip (1 case, 8.3%) and other combined causes. The sensitivity and specificity of the postoperative MCTA was 81.8% and 88.9%, respectively, by ROC curve (p=0.000). CONCLUSION: MCTA is an accurate noninvasive imaging method used for the assessment of clipped aneurysms in the anterior circulation. If the image quality of postoperative MCTA is good quality and the patient has been treated with a single titanium clip, except a fenestrated clip, the absence of an aneurysm remnant can be diagnosed by MCTA alone and the need for postoperative DSA can be reduced in a large percentage of cases.

Role of Multislice Computerized Tomographic Angiography in Vasospasm Following Aneurysmal Subarachnoid Hemorrhage

OBJECTIVE: We evaluate the role of multislice computerized tomographic angiography(MCTA) in the diagnosis of intracranial vasospasm following subarachnoid hemorrhage(SAH) in patients suspected of having vasospasm on clinical ground. METHODS: Between October 2003 and June 2005, patients with ruptured cerebral aneurysms of the anterior circulation clipped within 3 days of the onset were included. We performed follow-up MCTAs in patients who were suspected to have vasospasm on transcranial doppler sonography(TCD) findings and clinical grounds. Based on the clinical presentation of symptomatic vasospasm, we investigated the correlation between clinical, TCD, and MCTA signs of vasospasm and evaluated the role of MCTA in vasospasm. RESULTS: One hundred one patients met the inclusion criteria and symptomatic vasospasm developed in 25 patients (24.8%). We performed follow-up MCTAs in 28 patients. MCTA revealed spasm in the vessels of 26 patients. The sensitivity of MCTA was 100%. Among the 26 patients with MCTA evidence of vasospasm, 3 patients had TCD signs of vasospasm after symptomatic vasospasm presentation. Another 3 patients with symptomatic vasospasm had no TCD signs of vasospasm in daily serial recordings. Six other patients without symptomatic vasospasm showed MCTA evidence of vasospasm (false positive result) but these patients had also positive TCD signs of vasospasm. Volume rendering(VR) images tended to show significantly more exaggerated vasospasm than maximum intensity projection(MIP) images. The mean cerebral blood flow velocity of both proximal segment of the middle cerebral artery (M1) was significantly correlated with each reduced M1 diameter on MCTA (P<0.05). CONCLUSION: MCTA could be a useful tool for evaluation and planning management of critically ill patients suspected of having vasospasm; however, more randomized controlled trials are necessary to assess these points definitively.

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

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.