The postoperative evaluation of subtraction CT angiography in the clipped intercranial aneurysms

Objective:To evaluate MSCT with the subtraction CT angiography technique in following up the patients with clipped aneurysms. Methods: Thirty consecutive patients with clipped aneurysms were studied with the aid of postoperative MSCT and DS angiographies. CT raw data were reconstructed with volume rendering (VR) and maximum intensity projection (MIP) techniques to display the vessels. Assessed the site of the clip and patency of the parent vessel reviewed both CT and DSA studies independently. Result: The clips of 27 patients appeared clearly on the subtraction CT angiography image and the rest 3 patients′ clips were cut together with the skull because of their close density, which clips were viewed by the CTA; Subtraction CT angiography demonstrated 2 patients with a partial remnant lesions and 28 complete occlusion of aneurysms; In one patient, occlusion of a parent vessel was observed on DS angiograms but missed on MSCT angiograms. All the parent arteries appeared clearly on Subtraction CT angiography with one vessel′s occlusion and one stenosis. The sensitivity and specificity for detecting neck remnants on MSCT angiography were 67% and 100%, and the sensitivity and specificity for evaluating vessel potency were 100% and 100%, respectively. Inter-observer agreements were 0.78 and 1.00, respectively. Conclusions: Subtraction CT angiography is an accurate noninvasive tool used for assessment of clipped aneurysms, which can demonstrate both the patency of the vessels and the location of the clips.