Demonstration of circumferential heterogeneity in displacement and strain in the abdominal aortic wall by spiral cine DENSE MRI

Background Knowledge of tissue properties of the abdominal aorta can improve understanding of vascular disease and guide interventional approaches. Existing MRI methods to quantify aortic wall displacement and strain are unable to discern circumferential heterogeneity. Purpose To assess regional variation in abdominal aortic wall displacement and strain as a function of circumferential position using spiral cine displacement encoding with stimulated echoes (DENSE). Study Type Prospective. Population Cardiovascular disease‐free men (n = 8) and women (n = 9) ages 30–42. Sequences Prospective electrocardiogram (ECG)‐gated and navigator echo‐gated spiral, cine 2D DENSE and retrospective ECG‐gated phase contrast MR (PCMR) sequences at 3T. Assessment In‐plane displacement values of the aortic wall acquired with DENSE were used to determine radial and circumferential aortic wall motion. A quadrilateral‐based 2D strain calculation method was implemented to determine strain from the displacement field. Peak displacement and its radial and circumferential contributions as well as peak circumferential strain were compared among eight circumferential wall segments. Distensibility was calculated using PCMR and compared with homogenized circumferential strain. Statistical Tests To account for repeated measurements in volunteers, linear mixed models for mean sector values were created for displacement magnitude, circumferential displacement, radial displacement, and circumferential strain. Comparisons were made between sectors. Calculated distensibility and homogenized circumferential strain were compared using Bland–Altman analysis. Statistical significance was defined as P