4D flow MRI of the aorta demonstrates age- and gender-related differences in aortic size and blood flow velocity in healthy subjects

Methods 65 healthy subjects (age=43±14 yrs, 20 females) underwent aortic 4D flow MRI as part of an IRB-approved protocol. A 3D phase-contrast angiogram was generated from the 4D flow data followed by 3D segmentation of the aortic lumen. A volume centerline was calculated based on the aorta 3D segmentation and used to automatically characterize aortic diameter (AoD) and peak velocity (PV). Standardized anatomic landmarks (sinotubular junction [STJ], branchiocephalic trunk [BCT], left subclavian artery [LSA], and descending aorta [DAo]) were used to normalize the measurements along the length of the aorta length. AoD and PV association with age and gender were assessed by Pearson’s correlation and a Wilcoxon rank sum test was used to compare subjects by age (threshold 45 yrs) and gender.