Supplementary Material for: Morphological Classification of Mobile Plaques and Their Association with Early Recurrence of Stroke T.Ogata M.Yasaka Y.Wakugawa T.Kitazono Y.Okada 2010 <i>Background:</i> The present study investigated the frequency and morphological characteristics of carotid mobile plaques and examined the relationship between carotid mobile plaques and recurrent strokes. <i>Methods:</i> The study included 94 consecutive acute stroke patients with large-artery atherosclerosis associated with extracranial carotid stenosis. We investigated the presence of mobile plaques by carotid ultrasonography and classified patients into two groups (mobile group and non-mobile group). We compared backgrounds, MRI and ultrasonographic findings, neurological severity on admission and at discharge, and the rate of early recurrent stroke between both groups. <i>Results:</i> Mobile plaques were detected in 12 patients (12.8%). There were four types of mobile plaques: (1) the jellyfish-type plaque, in which the fibrous cap fluctuated like a jellyfish; (2) the streaming-band-type plaque, in which the string attached to the plaque was swaying; (3) the mobile-thrombus-type plaque, in which a mobile mass was attached to the plaque surface, and (4) the fluctuating-ulcer-type plaque, which contained a mobile substance in the plaque ulcer. Although National Institutes of Health Stroke Scale (NIHSS) scores on admission were less severe in the mobile group than in the non-mobile group (median 1 vs. 4, respectively; p = 0.004), the rate of early recurrent stroke was significantly higher in the mobile group than in the non-mobile group (33.3 vs. 7.3%, respectively; p = 0.022). There were no significant differences in NIHSS scores at discharge between groups. <i>Conclusions:</i> Morphologically, several types of mobile plaques were detected in consecutive patients with acute stroke associated with carotid stenosis. Mobile plaques are strongly associated with an early recurrence of stroke.