Black-blood vessel wall magnetic resonance imaging – A new imaging biomarker for regrowth of coiled saccular aneurysms?

Abstract

Background: Vessel wall imaging (VWI) of cerebral aneurysms is a new tool to risk stratify unruptured aneurysms. We hypothesized that the degree and pattern of aneurysm wall enhancement may predict the regrowth of these aneurysms. The aim of this study was to identify patient risk factors and VWI parameters associated with aneurysm regrowth. Methods: We retrospectively reviewed 71 saccular aneurysms and 75 follow-up VWI studies in patients who underwent the coil embolization procedure for unruptured saccular aneurysm. The relationship between VWI enhancement and aneurysm regrowth was analyzed by Pearson's chi-square test. Diagnostic performance of VWI enhancement in the diagnosis of regrowth aneurysm was determined to compare with digital subtraction angiography (DSA), and contrast-enhanced magnetic resonance angiography (CE-MRA) or time-of-flight MRA (TOF-MRA). Inter-rater agreement was measured by Cohen's kappa coefficient. Results: Fourteen of 71 aneurysms (19.71%) were categorized into the aneurysm regrowth group, while aneurysm wall enhancement was found in 55 studies (73.33%). All wall enhancements were found in the aneurysm regrowth group, and no significant association was found between aneurysm regrowth and patient risk factors or VWI parameters. The diagnostic performance parameters of VWI relative to the DSA, and CE-MRA or TOF-MRA results were 100% sensitivity, 38.5% specificity, 30.4% positive predictive value, 100% negative predictive value, and 52% accuracy. Conclusions: Wall enhancement of post-coil embolization of saccular aneurysm on VWI may be used as a screening imaging test to predict aneurysm regrowth, and may help to identify an unstable aneurysm, if the degree of enhancement increase or change of the pattern.