Bilateral symmetry of human carotid artery atherosclerosis

Background and Purpose - Atherosclerosis is a principal cause of stroke and myocardial infarction. The carotid arteries provide a site at which progression of atherosclerosis can be monitored reproducibly and noninvasively. This study was conducted to determine the similarity of atherosclerotic plaques in the left and right carotid arteries. This question was explored with the use of perfusion-fixed cadaveric carotid arteries and 2 noninvasive clinical imaging techniques, MRI and electron-beam CT. Methods - Fifty pairs of carotid arteries from cadaveric donors (aged 48 to 98 years) were imaged with MRI and electron-beam CT. Thirty-eight of the pairs met the criteria for rigorous analysis. Carotid artery wall volumes were measured from the MRI images, and calcification scores were computed from the electron-beam CT images. Results - Total wall volumes of the left (972.5±241.6 mm³) and right (1016.3±275.0 mm³) carotid arteries were moderately correlated (concordance correlation coefficient [r_c]=0.71). Calcification scores were highly correlated, with r_c=0.95 for the Agatston scores and r_c=0.94 for the calcium volume scores. Conclusions - Total wall volume and plaque calcification in the left and right human carotid arteries are substantially similar. These results suggest that atherosclerosis of the human carotid arteries is generally a bilaterally symmetrical disease. This evidence of symmetry suggests that diagnostic information about atherosclerotic plaque in one carotid artery can be used to infer information about the composition and volume of atherosclerotic plaque in the contralateral artery.