Relative Aortic Blood Pressure Using 4D Flow MRI: Associations with Age and Aortic Tapering

MOUSSEAUX, E; HOURIEZ S; CRAIEM D; KACHENOURA N; DE CESAR A; SOULAT G; BOUAOU K; GENCER U; DIETENBEK T; BARGIOTAS I

Rennes

Conferencia; Computers in cardiology; 2017

MRI 4D flow velocity is used to evaluate relativeblood pressures in the aorta throughout the cardiac cycle.This (3D+t) pressure mapping is used to assess: 1)relationship between trans-aortic pressure gradient withage and aortic tapering (proximal to distal narrowing inlumen area), 2) effect of temporal resolution.We studied 47 healthy subjects (49±17.6 years, 24men) who underwent 4D flow MRI, among them 20 werereconstructed in 20 and 50 phases per cardiac cycle.Pressure gradients maps were estimated from velocityfields using the Navier-Stokes equations. Relativepressures were calculated using an iterative algorithmwhile considering a zero pressure at the aortic valve.Distal (DA) to proximal (PA) aortic pressure gradientdecreased with age (r=0.60, p<0.05) and was inverselyrelated to DA/PA areas ratio (r=0.35, p<0.05). Suchresult is in line with the physiological evidence indicatingthat in aging DA area tends to equalize with PA arealowering the DA to PA pressure gradient. Peak systolicpressure was higher when considering the 50 phasesdata. Relative pressures calculated from 4D flow withinthe whole aortic volume through time are consistent withprior physiological knowledge as demonstrated by theirvariations with age and with aortic geometry.