In:
NMR in Biomedicine, Wiley, Vol. 27, No. 7 ( 2014-07), p. 826-834
Abstract:
Wall shear stress (WSS) is involved in many pathophysiological processes related to cardiovascular diseases, and knowledge of WSS may provide vital information on disease progression. WSS is generally quantified with computational fluid dynamics (CFD), but can also be calculated using phase contrast MRI (PC‐MRI) measurements. In this study, our objectives were to calculate WSS on the entire luminal surface of human carotid arteries using PC‐MRI velocities (WSS MRI ) and to compare it with WSS based on CFD (WSS CFD ). Six healthy volunteers were scanned with a 3 T MRI scanner. WSS CFD was calculated using a generalized flow waveform with a mean flow equal to the mean measured flow. WSS MRI was calculated by estimating the velocity gradient along the inward normal of each mesh node on the luminal surface. Furthermore, WSS was calculated for a down‐sampled CFD velocity field mimicking the MRI resolution (WSS CFDlowres ). To ensure minimum temporal variation, WSS was analyzed only at diastole. The patterns of WSS CFD and WSS MRI were compared by quantifying the overlap between low, medium and high WSS tertiles. Finally, WSS directions were compared by calculating the angles between the WSS CFD and WSS MRI vectors. WSS MRI magnitude was found to be lower than WSS CFD (0.62 ± 0.18 Pa versus 0.88 ± 0.30 Pa, p 〈 0.01) but closer to WSS CFDlowres (0.56 ± 0.18 Pa, p 〈 0.01). WSS MRI patterns matched well with those of WSS CFD. The overlap area was 68.7 ± 4.4% in low and 69.0 ± 8.9% in high WSS tertiles. The angles between WSS MRI and WSS CFD vectors were small in the high WSS tertiles (20.3 ± 8.2°), but larger in the low WSS tertiles (65.6 ± 17.4°). In conclusion, although WSS MRI magnitude was lower than WSS CFD , the spatial WSS patterns at diastole, which are more relevant to the vascular biology, were similar. PC‐MRI‐based WSS has potential to be used in the clinic to indicate regions of low and high WSS and the direction of WSS, especially in regions of high WSS. Copyright © 2014 John Wiley & Sons, Ltd.
Type of Medium:
Online Resource
ISSN:
0952-3480
,
1099-1492
Language:
English
Publisher:
Wiley
Publication Date:
2014
detail.hit.zdb_id:
2002003-X
detail.hit.zdb_id:
1000976-0
