Abstract 162: Microhemorrhages in MRI Predict Infectious Intracranial Aneurysm in Infective Endocarditis

Abstract

Background: MRI features such as cerebral microbleeds and sulcal susceptibility weighted imaging (SWI) or gradient-echo T2* (GRE-T2*) lesions have been reported to be associated with the presence of infectious intracranial aneurysm (IIA) in infective endocarditis (IE). We aimed to describe the MRI imaging features that predict the presence of IIA. Methods: The derivation cohort comprised 116 IE patients with neurological evaluation at a single tertiary referral center from January 2015 to July 2016. The MRI predictors associated with IIA was evaluated, and we developed the MRI imaging predictors and assessed sensitivity and specificity. External validation was performed in a cohort of 129 IE patients who underwent digital subtraction angiogram (DSA) at the same center from 2010-2014. We assessed the validity using a receiver operating characteristic curve (ROC). Results: Of 116 IE patients in the derivation cohort, 10 (9%) had IIAs. Of 129 in the validation cohort, 19 (15%) IIAs were identified. The MRI imaging predictors for IIA consist of 1) contrast enhancement with SWI lesions, 2) cerebral microbleeds > 5mm plus sulcal SWI lesions, and 3) any MRI hemorrhages. The sensitivity for the presence of IIA in each group of the derivation cohort was: 90%, 80%, and 100%, respectively. The sensitivity in the validation cohort was: 47%, 68%, and 94% respectively. The specificity in the derivation cohort was: 87%, 85%, and 18%. In the validation cohort, the specificity was similar (87%, 75%, and 27%). Conclusions: The suggested MRI imaging predictors can be used as a sensitive and specific tool to support clinical decision-making, especially when invasive DSA is considered for assessment for presence of IIA. The absence of MRI hemorrhages may not necessitate the need for DSA.