MRA of hemodialysis access grafts and fistulae using selective contrast injection and flow interruption

MR is a potentially attractive modality for evaluating hemodialysis access anatomy and function. However, the wide range of flow rates in the hemodial ysis access complicates interpretation of phase contrast, time-of-flight, a nd even contrast-enhanced MR angiograms, At high flow rates, signal voids m ay easily arise at mild narrowings or sharp-angled anastomoses. A method is proposed which Visualizes hemodialysis accesses without flow artifacts. Di luted Gd-DTPA is hand-injected directly into the access, while a cuff is us ed to reduce and subsequently interrupt access flow. Filling of the access is monitored using a fast projection technique with complex subtraction. Wh en filling is satisfactory, a 3D acquisition is started. The feasibility of this selective contrast-enhanced MR angiography technique is demonstrated in four Cimino-fistulae and four PTFE grafts. Magn Reson Med 45: 557-661, 2 001. (C) 2001 Wiley-Liss, Inc.