[Hemodynamic analysis of pulsatile blood flow in arteries by MRI].

The purpose of this study was to analyze the hemodynamics of pulsatile blood flow in arteries by MRI. The blood flow velocity was calculated by dividing the traveled distance of blood bolus by the echo time obtained from DBI images. Pulsatile water flow in the phantom and blood flow in abdominal aorta of 27 volunteers were estimated by means of both the DBI image and an approximate equation of flow velocity. The measured flow well agreed with the actual flow in the flow phantom study. Three-dimensional flow velocity profiles calculated using the approximate equation were similar to the DBI images and had the characteristics of pulsatile flow. The negative flow velocity near the aortic wall could be expressed in the flow velocity profiles by the approximate equation. The maximum flow velocities at the center of the abdominal aorta and the time-averaged wall shear stress calculated by the approximate equation decreased with aging (r = -0.78 P < 0.0001 and r = -0.64 P < 0.0003, respectively). The present results suggest that the DBI method and analysis based on the approximate equation proposed here will be valuable to analyze the hemodynamics of pulsatile blood flow.