['To retrospectively assess the relationship between carotid intraplaque hemorrhage (IPH), which indicates plaque instability, and brain white matter hyperintense lesions (WMHLs) by using a within-patient design.', 'All patients gave written informed consent for the initial magnetic resonance (MR) studies, and the institutional review board and local research ethics committee waived initial informed consent for the pooled analysis. A total of 190 patients with symptomatic carotid artery disease underwent fluid-attenuated inversion-recovery imaging of the brain and fat-suppressed black-blood T1-weighted MR imaging of the carotid arteries. The volumes of periventricular lesions, subcortical lesions, and total WMHLs were calculated and compared between hemispheres in relation to symptoms and IPH, and their interaction was calculated and compared by using repeated measures three-factorial multivariate analysis.', 'After exclusion of 12 patients, 178 patients (116 men, 62 women; mean age, 70.2 years +/- 8.6 [standard deviation]) remained. There was no significant difference in WMHL volume between the symptomatic and asymptomatic hemispheres, and WMHL volume was not related to the degree of carotid stenosis. The presence of carotid IPH significantly interacted with the interhemispheric WMHL difference (Wilks lambda test, F = 9.95; df = 3; P < .001). Univariate analysis showed larger total and periventricular WMHL volumes (P < .05) in patients with ipsilateral IPH.'] Are brain white matter hyperintensities associated with carotid intraplaque hemorrhage?