Background: High-resolution contrast-enhanced magnetic resonance imaging (CEMRI) has been proven to be an effective tool for the identification of carotid atherosclerotic vulnerable plaque, such as a large lipid core and thin fibrous cap. The aim of this study was to evaluate the relationship between carotid plaque characteristics and the types of stroke in patients who had carotid artery (CA) stenosis >= 50%. Methods: 102 consecutive subjects (mean age 67.2 +/- 10.2 years; 73 males) who initially had ischemic stroke or asymptomatic CA stenosis from 50 to 100% diagnosed by ultrasound were included in this study. Carotid CEMRI, brain MRI and magnetic resonance angiography were performed to understand the infarct patterns and to exclude intracranial artery stenosis. The modified American Heart Association (AHA) plaque classification was used in our study. Results: Our study demonstrated that 45 patients had CA stroke, and 55 patients had lacunar and asymptomatic lesions. The majority of patients had AHA classification type IV-V and VI which presented as vulnerable plaques. Of 63 patients with mild to moderate stenosis (<= 70%), 44 (69.8%) had type IV-V vulnerable plaques, which was significantly higher than those of patients with severe stenosis (>70%; p < 0.001). In CA stroke, the number of patients with a thin or ruptured fibrous cap was twice that of those with a thick and intact fibrous cap. Conclusions: CEMRI may have important applications in clinical risk evaluations in CA atherosclerosis. Physicians ought to recognize that different types of stroke should be identified by brain MRI detection before invasive therapies. Copyright (C) 2009 S. Karger AG, Basel