Coupling of vessel wall morphology and function in the aorta and the carotid artery: an evaluation with MRI.

To evaluate the regional association between vessel wall morphology [i.e. cross-sectional vessel wall area (VWA)] and function [i.e. wall stiffness expressed in the pulse wave velocity (PWV)] in both the aortic arch and the left carotid artery. Thirty-two healthy volunteers (mean age 41 ± 16 years) underwent 3T MRI examination to assess PWV and VWA of the aorta and the left carotid artery. PWV was determined by the transit-time method with velocity-encoded MRI recordings of the systolic blood flow propagation. VWA was assessed for both the aorta and the carotid artery, by detecting lumen and outer vessel wall contours in cross-sectional black blood images. Linear regression analyses were used to test associations between aortic and carotid vessel wall area and stiffness. Within the same vascular territory, correlation between PWV and VWA was stronger than across vascular territories. For the aorta, the correlation between PWVAO and VWAAO (r = 0.71, p < 0.0001) was stronger than between PWVAO and VWACA (r = 0.53, p = 0.002). For the carotid artery, the correlation between PWVCA and VWACA (r = 0.61, p < 0.0001) was stronger than between PWVCA and VWAAO (r = 0.46, p = 0.008). Morphologic and functional vessel wall properties assessed in the aortic arch and the left carotid artery are significantly stronger associated within the same vascular territory rather than across different vascular territories.