Vessel Wall Imaging Predicts the Presence of Atherosclerotic Lesions in Unruptured Intracranial Aneurysms

Abstract

Recent studies have suggested that magnetic resonance vessel wall imaging (VWI) can visualize thickened intracranial aneurysm wall. We aimed to investigate correlations between VWI findings and intraoperative aneurysm wall features based on the hypothesis that VWI can visualize atherosclerotic changes in unruptured intracranial aneurysm (UIA) walls. A total of 36 microsurgically treated UIAs were retrospectively reviewed. All aneurysms underwent VWI before microsurgical clipping, and fusion images with time-of-flight magnetic resonance angiography were created to localize aneurysm wall enhancement (AWE) lesions. Intraoperatively, 2 neurosurgeons who were blinded to the VWI findings evaluated the aneurysm wall features, giving each aneurysm an atherosclerosis score on a 5-point scale (5: yellowish, 4: whitish, 3: normal, 2: slightly reddish, 1: reddish). We defined atherosclerotic lesions as those having average scores ≥4. We evaluated the rate of correspondence between AWE lesions and atherosclerotic lesions, and the factors associated with AWE. Sixteen of the 36 UIAs (44%) were identified as AWE. The sensitivity, specificity, positive predictive value, and negative predictive value of correspondence between AWE lesions and atherosclerotic lesions were 79%, 94%, 94%, and 80%, respectively. The average atherosclerosis scores (4.2 ± 0.5 vs. 2.7 ± 0.9; P < 0.001) were significantly higher in aneurysms with AWE. Twelve of 16 UIAs with wall enhancement had wall thinning adjacent to the part with AWE. AWE lesions corresponded with intraoperatively confirmed atherosclerotic lesions of UIAs. Detecting these lesions would be valuable in exploring UIAs with wall degeneration.