Wall enhancement in unruptured posterior communicating aneurysms with oculomotor nerve palsy on magnetic resonance vessel wall imaging

OBJECTIVE Recent MR vessel wall imaging studies of unruptured intracranial aneurysms (UIAs) have revealed that aneurysm wall enhancement (AWE) can be an indicator for aneurysm evolution; however, the degree of AWE among different types of evolving UIAs has yet to be clarified. The authors assessed the degree of AWE in unruptured posterior communicating artery (PcomA) aneurysms with oculomotor nerve palsy (ONP), which may be a subgroup of evolving UIAs with rapid enlargement and high rupture risk. METHODS The degree of AWE was analyzed in 35 consecutive evolving PcomA aneurysms (19 with and 16 without ONP). UIAs were considered to be evolving when showing growth or ONP. A 3D 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 indicator of AWE. The CR stalk in evolving UIAs with ONP was compared with that in UIAs without ONP. RESULTS The CR stalk was significantly higher in evolving UIAs with ONP than in those without ONP (0.85 vs 0.57; p = 0.006). In multivariable analysis, the CR stalk remained a significant indicator for ONP presentation in evolving UIAs (OR 6.13, 95% CI 1.21–31.06). CONCLUSIONS AWE was stronger in evolving PcomA aneurysms with ONP than in those without ONP, suggesting the potential utility of AWE for risk stratification in evolving UIAs. The degree of AWE can be a promising indicator of a rupture-prone UIA, which can be useful information for the decision-making process in the treatment of UIAs.