Abstract 3703: Utility of Cardiac MRI in Evaluation of Stroke Subtypes

Abstract

Introduction : Cardiac magnetic resonance imaging (CMR) is a novel imaging modality that may aid in identifying potential cardiac etiology of ischemic stroke. We assessed the prevalence of cardiac abnormalities by the CMR in a population of patients with acute stroke. Patients and Methods : We performed CMR on 89 patients who were admitted to our stroke service between August 2009 and June 2011. None of these patients had MRI contraindication. Of those, 13 patients were excluded due to negative diffusion weighted MRI, one was excluded for having intracranial bleeding, and one for having vertebral artery dissection as the source of stroke. The remaining 74 patients with DWI positive or CT positive acute stroke were analyzed for abnormalities on cardiac MRI. CMR along with other routine stroke work up including MRI of the brain and MRA of head and neck were done for these patients within the first 48 hours of their admission. We consider cardioembolic etiology as definite, probable, or possible based on the presence of an abnormality on the CMR. We consider atherothrombotic etiology as definite, probable, or possible if there was a 50% or greater arterial stenosis identified in the territory of the infarct. Results : In our 74 patients, we found definite cardioembolic source in 21 patients (28.3%), definite atherothrombotic source in 14 patients (18.9%) and no definite etiology in 12 patients (16.2%).In the other patients (36.4%), there was at least one abnormality in CMR or MRA head /neck which could be considered as the probable or possible etiology of acute stroke. In the patients with definite cardioembolic source (21 patients), enlargement of left atrium were found in 9 (43%), systolic dysfunction in 6 (29%), mural thrombus in 5 (24%), mural scar in 4 (19%), myocardial infarction in 2 (9%) and cardiac mass in 1 (5%). Conclusion: CMR is an effective non-invasive modality in diagnosing cardioembolic etiologies in patients with stroke. Further studies to compare the effectiveness of CMR with other modalities such as transesophageal echocardiography are recommended.