Aneurysm Wall Enhancement Can Predict Rupture Point in Intracranial Aneurysms With Multiple Blebs.

Abstract

Ruptured aneurysms visualized by vessel wall MRI (VW-MRI) exhibit characteristic aneurysm wall enhancement (AWE). A secondary bulge of the aneurysmal wall, called a bleb, is often the site of rupture in ruptured aneurysms. We hypothesized that a higher degree of AWE would identify the rupture point in aneurysms with multiple blebs. AWE was quantitatively analyzed in consecutive ruptured intracranial aneurysms with multiple blebs (31 aneurysms with a total of 72 blebs) using VW-MRI. A 3-dimensional T1-weighted fast spin-echo sequence was obtained after contrast media injection, and the contrast ratio of the aneurysm wall against the pituitary stalk (CR stalk ) was calculated as the AWE indicator. Bleb characteristics, including CR stalk and wall shear stress (WSS), were compared between ruptured and unruptured blebs. Odds ratios with 95% confidence intervals for ruptures were calculated by conditional logistic regression analysis. Ruptured blebs had a higher CR stalk and lower WSS compared with unruptured blebs. CR stalk remained significantly associated with the bleb rupture status in the conditional logistic regression (adjusted odds ratio 3.9, 95% CIs 1.6-9.7). AWE is associated with the bleb rupture status independent of WSS. Contrast-enhanced VW-MRI may be a useful noninvasive tool for identifying the rupture point and guiding the treatment strategy.