Comparison of wall shear stress estimates obtained by laser Doppler velocimetry, magnetic resonance imaging and numerical simulations

The wall shear stress (WSS) acting on human vessel walls may play an important role in the emergence of cardiovascular diseases such as aneurysms or arteriosclerosis and is of great interest in the medical context. Magnetic resonance velocimetry (MRV) is a possible method to measure this quantity; however, the most appropriate procedure for the measurement and the achievable accuracy are open and controversial topics. In this study, we examine the accuracy of WSS estimates obtained from in vitro MRV measurements by comparing results with those obtained using laser Doppler velocimetry, with numerical simulations and for some cases with analytic solutions, all for flow conditions typical of the human aorta. The comparisons indicate that under certain conditions, WSS measurements from MRV are feasible and reliable. This work forms the basis for a systematic assessment of WSS estimators using newly developed post-processing algorithms and is considered a first step to improving the in vivo measurements of wall shear stress. [GRAPHICS]