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

Abstract

Background and objectives: 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.

Methods: 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 (CRstalk) was calculated as the AWE indicator. Bleb characteristics, including CRstalk 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.

Results: Ruptured blebs had a higher CRstalk and lower WSS compared with unruptured blebs. CRstalk remained significantly associated with the bleb rupture status in the conditional logistic regression (adjusted odds ratio 3.9, 95% CIs 1.6-9.7).

Conclusion: 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.