Preferential arterial imaging using gated thick-slice gadolinium-enhanced phase-contrast acquisition in peripheral MRA

Purpose: To investigate the feasibility of preferential arterial Imaging us ing gadolinium-enhanced thick-slice phase-contrast imaging. Methods: Six he althy volunteers were studied using a peripheral-gated segmented k-space CI NE phase-contrast pulse sequence using four views per RR interval with flow encoding in the superior-inferior direction. Images at the level of the po piteal trifurcation were acquired postcontrast with different section thick nesses (4-8 cm) and VENC values (20-150 cm/sec), and phase-difference proce ssing. Results: The post-gadolinium contrast-enhanced thick-slice phase-con trast acquisitions demonstrated the ability to visualize the tibio-peroneal (trifurcation) arteries, especially in systole. With MR contrast agents, t he signal from blood is raised significantly above that of stationary tissu e from T-1 shortening such that the partial volume artifact is reduced in t hick-slice acquisitions. Furthermore, by selecting the VENC value as a func tion of the cardiac cycle, the noise floor can be raised to selectively sup press flow values less than that of the noise threshold, allowing better ac centuation of arterial structures at systole. Conclusions: Thick-slice phas e-contrast acquisition with phase-difference processing has been observed t o reduce partial volume artifacts when an MR contrast agent substantially i ncreases signal in the vasculature over that of normal background tissue. P referential arterial Images can be obtained by either increasing the VENC v alue to selectively suppress signal from slow flow in the veins or by subtr acting the diastolic phase image from the peak systolic phase image. (C) 20 01 Wiley-Liss, Inc.