Feasibility of aortic pulse pressure and pressure wave velocity MRI measurement in young adults

Abstract

Purpose:To investigate the feasibility of assessing, noninvasively, aortic pulse pressure (APP) and pulse wave velocity (PWV) in the ascending aorta of young adults by means of velocity-encoded magnetic resonance (MR) imaging. Materials and Methods:In a series of 11 healthy volunteers, velocity-encoded MR imaging provided pairs of magnitude and phase-contrast images. Blood flow velocity and aortic cross-sectional area (CSA) were determined with a 30-msec temporal resolution. A model analysis revealed that variation in aortic CSA and in maximal blood flow velocity throughout systole could be used to estimate APP and, hence, to derive PWV by means of two different methods. Results:Mean Ϯ SD values of the APP for the series were 54.2 Ϯ 16.4 mmHg (range 32.2-84.1 mmHg). The ascending aortic PWV mean Ϯ SD values were 5.03 Ϯ 1.10 m/second and 5.37 Ϯ 1.23 m/second according to the two methods, and both estimates were not significantly different (95% confidence level). Conclusion:These results are in agreement with previously published data, suggesting that APP and PWV can be determined, noninvasively, in young adults using MRI.

Quantification of the pulse wave velocity of the descending aorta using axial velocity profiles from phase‐contrast magnetic resonance imaging

“…Multivariate analysis showed that both age and CAD were independent risk factors and significantly correlated with the increase in PWV. The results are consistent with data reported in the literature (4,13,23).…”

“…With the use of phase-contrast magnetic resonance imaging (PC-MRI), PWV can be measured from the slope of the curve of aortic flow plotted against aortic area in systole (12,13), or from the ratio of the traveling distance to the traveling time of the pulse wave (12,14). Although these methods are applicable by noninvasive means, and hence are feasible in the clinical setting, they are subject to inaccuracies owing to assumptions or simplifications made in individual methods.…”

“…Although these methods are applicable by noninvasive means, and hence are feasible in the clinical setting, they are subject to inaccuracies owing to assumptions or simplifications made in individual methods. In the flow-area changing ratio method, which has been dubbed the flow-area (QA) method (12,13), a constant aortic compliance over a range of pressures from diastole to peak systole is assumed. This assumption, however, is contradictory to findings obtained from invasive measurements, which showed a viscoelastic property of human aortic tissue (6,15).…”

Compliance and pulse wave velocity assessed by MRI detect early aortic impairment in young patients with mutation of the smooth muscle myosin heavy chain

“…By considering the arterial blood volume to be the aortic cross-sectional area multiplied by the slice thickness, and as the slice thickness is constant, the precedent equation becomes (28,29):…”

Estimation of global aortic pulse wave velocity by flow‐sensitive 4D MRI

“…To provide a noninvasive estimate of PWV, phase contrast (PC) MRI has been applied in a number of in vivo studies determining blood flow based on flow waveform measurements in single two-dimensional (2D) planes transecting the aorta (8)(9)(10). For PWV estimation, typically transit-time methods are employed estimating temporal differences of specific features of blood flow waveforms, e.g., time from foot to foot or peak to peak, between two locations of the vessel with known distance (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24). However, the precision of this method highly depends on the exact calculation of flow difference and distance between only two measuring points (16,25,26).…”