Associations between cardio-ankle vascular index score and aortic volume and hemodynamic parameters using four-dimensional magnetic resonance imaging

Backgroud The cardio-ankle vascular index (CAVI) is a noninvasive measure of aortic atherosclerosis (AA), but it does not assess blood flow or aortic shape. Four-dimensional (4D) magnetic resonance imaging (MRI) has emerged as a promising tool for evaluating vascular blood flow. This study investigated the correlation between thoracic aortic volume (TAV) and hemodynamic parameters using 4D MRI in patients with and without AA as defined by the CAVI score. Methods This retrospective study involved 171 patients (77 with a low CAVI score and 94 with a high CAVI score) who underwent cardiac MRI with a 4D flow sequence. Hemodynamic parameters—including energy loss (EL), vorticity (Vort), and helicity (Hel)—were obtained. Results Patients in the high CAVI group had significantly larger TAV (113.6 ± 29.3 vs. 80.6 ± 30.5 cm ³ , P < 0.0001). The TAV was positively correlated with the CAVI score (R = 0.4147, P < 0.0001). EL maximum/TAV ( P = 0.0035), Vort average/TAV ( P = 0.0004), and Hel absolute maximum/TAV ( P = 0.0002) were significantly lower in the high CAVI group. Several hemodynamic parameters, including Vort maximum/TAV (R = −0.4082, P < 0.0001) and Hel right screw maximum/TAV (R = −0.4211, P < 0.0001), were moderately negatively correlated with the CAVI score, suggesting that aortic stiffness restricts luminal blood flow, particularly during systole. Conclusions Patients with high CAVI scores exhibited a larger TAV and lower voxel-based hemodynamic parameters than those with low CAVI scores. This method represents a novel approach for the noninvasive assessment of atherosclerosis.