Immediate intracranial aneurysm occlusion after embolization with detachable coils: a comparison between MR angiography and intra-arterial digital subtraction angiography

Abstract

Background and purpose To prospectively compare the effectiveness of time-of-flight (TOF) and contrast-enhanced (CE) MR angiography (MRA) with that of digital subtraction angiography (DSA) to assess immediate intracranial aneurysm occlusion after selective embolization. Methods From August 2006 to March 2007, 33 consecutive patients with 40 aneurysms were included. Thirty aneurysms were treated by endosaccular coils (group 1). Ten aneurysms were treated by stent placement and subsequent endosaccular coils (group 2). All patients underwent MRA within 24 h after treatment. One senior and one fellow radiologist independently reviewed the MR images, and another senior radiologist reviewed the DSA images. Results DSA showed 22 complete occlusions, ten residual necks, and eight residual aneurysms. For residual neck detection, there was no difference between TOF-MRA (sensitivity, 80%–80%; specificity, 93.8%–100%, according to both readers) and CE-MRA (sensitivity, 80%–80%; specificity, 100%). For residual aneurysm detection, there was a significant difference between TOF-MRA (sensitivity, 50%–62.5%; specificity, 100%) and CE-MRA (sensitivity and specificity, 100%, according to both readers). In group 2, a residual aneurysm was missed by both readers with TOF-MRA in the same 3 aneurysms. Moreover, both readers judged CE-MRA better than TOF-MRA to assess parent-artery patency in group 2. Interobserver agreement was excellent for TOF-MRA and CE-MRA (κ = 0.9 and 1, respectively). Conclusions In our study, both TOF-MRA and CE-MRA had high and comparable sensitivity and specificity for the assessment of immediate aneurysm occlusion after selective embolization, except when a stent-assisted technique was used. In such cases, CE-MRA was superior to TOF-MRA to evaluate aneurysm occlusion and parent-artery patency.