Computed tomography–derived elastic modulus as a noninvasive marker of aortic wall integrity: Correlation with histopathology in the ascending aorta

Background: Ascending aortic aneurysms and dissections are life-threatening conditions often requiring prophylactic surgeries. Current guidelines rely primarily on aortic diameter for intervention; however, many dissections occur without severe dilation. Mechanical properties, such as elastic modulus, have emerged as potential predictors of disease progression; nonetheless, noninvasive clinical applications remain limited. This study evaluated the relationship between the computed tomography (CT)-derived elastic modulus of the ascending aorta and the histopathologic characteristics of the aortic media. Methods: Thirty patients who underwent surgical ascending aorta replacement were included in this study. Preoperative CT was used to calculate the aortic elastic modulus based on geometric measurements and pulse pressure. Resected aortic specimens were subjected to histologic and immunohistochemical analyses to assess elastin, collagen, vascular smooth muscle cells (VSMCs), and smoothelin expression. Correlation analyses between the CT-derived elastic modulus and aortic media composition were conducted after adjusting for age and aortic diameter. Results: The CT-derived elastic modulus exhibited a significant negative correlation with elastin area and a positive correlation with collagen area. Additionally, a moderate negative correlation was observed between the elastic modulus and elastin fiber waviness. A strong negative correlation was detected between the elastic modulus and the proportion of contractile-type (ie, smoothelin-positive) VSMCs. These findings remained significant after adjusting for confounders. Conclusions: CT-derived elastic modulus of the ascending aorta reflects underlying pathologic changes, including extracellular matrix remodeling and VSMC phenotypic modulation. Noninvasive assessment of aortic mechanical properties may provide novel insights into aortic disease progression and therapeutic responses.