In vivo magnetic resonance evaluation of atherosclerotic plaques in the human thoracic aorta: A comparison with transesophageal echocardiography

Background - The structure and composition of aortic atherosclerotic plaques are associated with the risk of future cardiovascular events. Magnetic resonance (MR) imaging may allow accurate visualization and characterization of aortic plaques. Methods and Results - We developed a noninvasive MR method, free of motion and blood flow artifacts, for submillimeter imaging of the thoracic aortic wall. MR imaging was performed on a clinical MR system in 10 patients with aortic plaques identified by transesophageal echocardiography (TEE). Plaque composition, extent, and size were assessed from T1-, proton density-, and T2- weighted images. Comparison of 25 matched MR and TEE cross sectional aortic plaque images showed a strong correlation for plaque composition (χ²=43.5, P<0.0001; 80% overall agreement; n=25) and mean maximum plaque thickness (r=0.88, n=25; 4.56±0.21 mm by MR and 4.62±0.31 mm by TEE). Overall aortic plaque extent as assessed by TEE and MR was also statistically significant (χ²=61.77, P<0.0001; 80% overall agreement; n=30 regions). Conclusions - This study demonstrates that noninvasive MR evaluation of the aorta compares well with TEE imaging for the assessment of atherosclerotic plaque thickness, extent, and composition. This MR method may prove useful for the in vivo study of aortic atherosclerosis.