Methodology for Optimal Quantitative Flow Analysis by planar analysis of CINE Phase Contrast 2D or 3D MR data

Introduction: Time-resolved (CINE) phase contrast (PC) MRI allows measurement of time resolved threedirectional velocities within entire 3D vascular structures [1, 2]. The information contained in the PC data is not limited to volumetric flow, but also includes derived quantities such as wall shear stress (WSS), the viscous drag of blood on the arterial wall, which is believed to play a key role in atherogenesis [3-6]. However, the lack of suitable analysis tools for the evaluation of complex 2D and 3D CINE PC MRI datasets still prevents the routine clinical use of such predictors. High dimensional 3D visualizations methods do exist but remain complex and permit only subjective and qualitative evaluation of blood flow characteristics. The purpose of this study was the development of quantitative analysis tools in order to derive flow parameters from CINE PC MR data. The method presented here combines accurate segmentation and robust data analysis methodologies into a planar analysis tool providing blood flow and vessel wall parameters [2]. Particular attention was given to methodological challenges such as arterial motion and limited resolution of the 2D or 3D CINE PC MRI data. Initial results in volunteer and patient studies of the thoracic aorta illustrate the potential of such parameters to characterize the link between disturbed blood flow and mechanical properties of the vessel wall. Furthermore, synthetic flow data was used to test the accuracy of the proposed quantification method.