Assess the impact of brain MRI/MRA on the diagnosis of neurologic complications of IE and on medical and surgical decision-making.

Neurologic complications occur in up to 55% of IE patients and lead to poor prognoses, making accurate diagnosis critical. Current guidelines recommend neuroimaging with neurologic symptoms or signs but do not explicitly recommend brain MRI. The American College of Radiology Appropriateness Criteria of IE does not address brain imaging.  A pooled analysis however found that MRI significantly influences diagnosis and decision-making.  Most studies have been small, and few have looked at the influence of MRI on medical and surgical decision-making.      

In 125 IE patients, 166 MRIs were performed. Indications for MRIs were nonspecific signs (41%), focal neurologic findings (28%) or other imaging findings suggesting systemic septic embolism (31%). MRI findings included ischemic stroke (22%), ICH (16%), septic emboli, defined as small punctate diffusion restriction or enhancement, (55%), microhemorrhages (11%), CNS infection (6%) and mycotic aneurysms (2%).  In 80% of the MRI studies, these new findings represented diagnoses not established by clinical findings or CT. Thirty-four percent of brain MRIs prompted a change in medical management, including adjustments of anticoagulants or antiplatelet agents (17%), prompting of further imaging (11%), determination to stop further testing (2%), change in medication (1%), Twelve percent of MRIs led to a change in surgical management, triggering surgery (7%) or delaying or contraindicating surgery (5%).