Plaque hemorrhage is a marker of thromboembolic activity in patients with symptomatic carotid disease

Purpose: To assess whether carotid plaque hemorrhage depicted with magnetic resonance (MR) imaging was associated with thromboembolic activity as assessed with transcranial Doppler imaging.

Materials and methods: The local research ethics committee approved the study, and all patients gave informed written consent. Between April 2005 and December 2006, patients with high-grade symptomatic carotid stenosis were prospectively recruited. All underwent MR imaging of the carotid arteries for plaque hemorrhage and diffusion-weighted imaging of the brain. Transcranial Doppler imaging of the symptomatic carotid artery was performed over 1 hour to assess the presence of microembolic signal. To determine the relationship between the presence of plaque hemorrhage and diffusion-weighted imaging-positive signal and presence of microembolic signal, a logistic regression analysis was performed.

Results: Fifty-one patients (23 women and 28 men; mean age ± standard deviation, 72 years ± 11) underwent complete MR imaging; 46 (86%) of these patients underwent complete transcranial Doppler imaging. In 32 (63%) patients, there was plaque hemorrhage in the index carotid artery. The presence of plaque hemorrhage increased the risk for ipsilateral abnormalities at diffusion-weighted imaging (odds ratio, 6.2 [95% confidence interval: 1.7, 21.8]; P < .05). Multiple diffusion-weighted imaging-depicted abnormalities of multiple ages were present exclusively in patients with plaque hemorrhage shown at MR imaging (12 of 32 [38%] patients with plaque hemorrhage versus none of 19 patients without plaque hemorrhage; P < .05). The presence of plaque hemorrhage also increased the presence of microembolic signal (odds ratio, 6.0 [95% confidence interval: 1.8, 19.9]; P = .003).

Conclusion: In patients with carotid plaque hemorrhage demonstrated at MR imaging, there was increased spontaneous microembolic activity at transcranial Doppler imaging and cerebral ischemic lesion patterns suggestive of recurrent embolic events; these findings suggest that plaque hemorrhage shown at MR imaging might be a marker of thromboembolic activity and further validate the usefulness of carotid imaging in identifying patients with active carotid arterial disease.