Cerebral Microhemorrhages and Meningeal Siderosis in Infective Endocarditis

Patients with infective endocarditis (IE) frequently experience cerebral insults, and neurological involvement in IE has been reported to herald a worse prognosis. In this manuscript, we describe a distinctive pattern of findings on susceptibility-weighted imaging (SWI) sequences in subjects with IE.

Patients with IE who underwent SWI MRI at an academic hospital from 2009 to 2014 were retrospectively analyzed. The pattern of findings was compared to SWI findings in groups of subjects with cerebral amyloid angiopathy (CAA) or severe hypertension.

Sixty-six subjects with IE were included; 64 (94%) had microhemorrhages and the average number per patient was 21.5. In 11 (17%) patients, microhemorrhages were the only neuroimaging abnormality. The majority of microhemorrhages were between 1 and 3 mm. In a direct comparison of gradient-echo T2* (GRE-T2*) and SWI, many microhemorrhages in this size range were not detected by GRE-T2*. Microhemorrhages in IE involved every part of the brain with a significant predilection for the cerebellum. This pattern was distinct from that seen in hypertension or CAA. Small subarachnoid hemorrhage or meningeal siderosis were also frequently detected in IE, but were not associated with mycotic aneurysms.

SWI is a sensitive diagnostic technique for detecting infectious cerebral angiopathy in subjects with IE, producing a pattern of microhemorrhages that were distinct from other common microangiopathies.