Wall shear stress calculations based on 3D cine phase contrast MRI and computational fluid dynamics: a comparison study in healthy carotid arteries. (12th May 2014)

• Record Type: Journal Article
• Authors: Cibis, Merih; Potters, Wouter V.; Gijsen, Frank J. H.; Marquering, Henk; vanBavel, Ed; van der Steen, Antonius F. W.; Nederveen, Aart J.; Wentzel, Jolanda J.
• Is Part Of: NMR in biomedicine. Volume 27:Number 7(2014:Jul.)
• Page Start: 826
• Page End: 834
• Publication Date: 2014-05-12
• Subjects: Nuclear magnetic resonance -- Periodicals; Magnetic Resonance Spectroscopy -- Periodicals; 574
• DOI: 10.1002/nbm.3126
• Languages: English
• ISSNs: 0952-3480

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <p>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<sub>MRI</sub>) and to compare it with WSS based on CFD (WSS<sub>CFD</sub>).</p> <p>Six healthy volunteers were scanned with a 3 T MRI scanner. WSS<sub>CFD</sub> was calculated using a generalized flow waveform with a mean flow equal to the mean measured flow. WSS<sub>MRI</sub> 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<sub>CFDlowres</sub>). To ensure minimum temporal variation, WSS was analyzed only at diastole. The patterns of WSS<sub>CFD</sub> and WSS<sub>MRI</sub> 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<sub>CFD</sub> and WSS<sub>MRI</sub> vectors.</p> <p>WSS<sub>MRI</sub> magnitude was found to be lower than WSS<sub>CFD</sub> (0.62 ± 0.18 Pa versus 0.88 ± 0.30 Pa, <italic>p</italic> < 0.01) but closer to WSS<sub>CFDlowres</sub> (0.56 ± 0.18 Pa, <italic>p</italic> < 0.01). WSS<sub>MRI</sub> patterns matched well with those of WSS<sub>CFD.</sub> The overlap area was 68.7 ± 4.4% in low and 69.0 ± 8.9% in high WSS tertiles. The angles between WSS<sub>MRI</sub> and WSS<sub>CFD</sub> vectors were small in the high WSS tertiles (20.3 ± 8.2°), but larger in the low WSS tertiles (65.6 ± 17.4°).</p> <p>In conclusion, although WSS<sub>MRI</sub> magnitude was lower than WSS<sub>CFD</sub>, 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.</p> </abstract>