MRI features of infarcts with potential cardiac source of embolism in the Yonsei Stroke Registry (YSR), Korea

The determination of the embolic source is crucial to understanding the pat hogenesis of ischemic stroke, the initiation of appropriate therapy, and th e prevention of recurrent infarctions. In this study we undertook to identi fy the characteristic features on magnetic resonance images of patients who had suffered from stroke due co cardiac embolism (CE), as classified by TO AST (possible and probable). We retrospectively studied magnetic resonance imaging (MRI) findings of patients with ischemic stroke from the Yonsei Str oke Registry (YSR). On the basis of the TOAST classification, 92 patients w ere identified to have a potential cardiac source of embolism (PCSE), in wh ich 69 patients were found to have high-risk PCSE and 23 patients medium-ri sk PCSE. To compare their imaging characteristics, another group of 49 pati ents who were found to have had a stroke due to large artery-to-artery (ATA ) embolism-common or internal carotid artery (CCA, ICA)-were identified. In volvement of the simultaneous superficial and deep territories (58.7%; 6.1% , p<0.001), and combined new anterior and old posterior circulation (15.2%; 2.0%, p=0.016) were more frequent in PCSE than ATA embolism. Bilateral ant erior hemispheric involvement was also more frequent in the PCSE group, but it did nor reach statistical significance (13.0%; 4.1%, p=0.090). ATA embo lism tended to involve only superficial territories compared to PCSE (71.4% ; 28.3%, p<0.001). There were no topographic differences between the high-r isk and medium-risk groups. With respect to the etiology of PCSE in our pop ulation, atrial fibrillation was the most common. Characteristic MRI featur es of patients with PCSE, which were not documented previously by computed tomography (CT) included: old and new, involvement of multiple different va scular territories, bilateral anterior hemisphere, as well as anterior and posterior circulation. These MRI features, together with simultaneous super ficial and deep territorial involvement, help to differentiate the underlyi ng embolic sources, whether they are cardiac or ATA in origin.