Abstract TP143: Longitudinal Evaluation of Vessel Wall MRI Demonstrates Bilaterally Symmetric Evolution of Carotid Atherosclerosis

Introduction: Carotid atherosclerosis is a leading cause of stroke worldwide. Previous studies demonstrated bilateral symmetry in atherosclerotic plaque burden and calcification scores. By leveraging longitudinal 3D vessel wall MRI, this study aims to investigate if there is a symmetrical trend of bilateral plaque progression. Methods: Asymptomatic patients with confirmed carotid stenosis were prospectively recruited in the study. Subjects underwent baseline and follow-up 3D vessel wall imaging for a time span up to 8 years. A deep learning-based pipeline was used to bilaterally segment the carotid lumen and vessel wall on axial image slices. Within each artery, the range of slices with wall thickness > 2mm on any scan was included as potential atherosclerotic plaque. Plaque burden, positively associated with stroke risk, was defined as the percent wall volume (wall volume / total vessel volume х 100%). For each plaque, a linear model was fitted across all available time points to determine the growth rate of plaque burden. We used generalized estimating equation-based linear regression models to evaluate associations of the growth rate of each side with the contralateral side, adjusted for clinical risk factors and medications. Effect sizes were summarized using the partial correlation coefficient. Results: 20 subjects (mean age 73.5 years, 3 females, 14 on statins) who underwent at least three scans with bilateral carotid plaque were included in the analysis. Each subject underwent an average of 4.8 scans over 5.2 years. Overall, the plaque growth rate of one side was moderately correlated with the contralateral side (r=0.50, p=0.004), even after adjusting for age, sex and statins use. Then, for each subject, the larger of the two plaques at baseline (left or right side) was identified. The growth rate of the larger plaque was also predictive of the growth rate of the smaller plaque over the same time period (r=0.66, p=0.004). Conclusion: The systemic nature of atherosclerotic disease entails an association in symmetrical disease evolution for left and right carotid arteries. In bilaterally diseased patients, the longitudinal monitoring of the more advanced carotid lesion may provide prognostic information on the less advanced contralateral plaque.