Preoperative examination of potential renal transplant donors: Value of gadolinium-enhanced 3D-MR-Angiography in comparison with DSA and urography.

Purpose: To assess a contrast-enhanced standardized MRA protocol for the pr esurgical evaluation of potential renal transplant donors. Methods: Twenty- three potential donors for renal transplantations were examined with gadoli nium-enhanced, two-phase MR angiograms (1.5 T) and DSA/urography for the nu mber of renal arteries, the presence of aberrant arterial and venous branch es, renal artery stenoses and anatomy of the renal collecting system and ur eters. The diagnostic value was assessed by evaluating different image proc essing modalities and interobserver variability. Results: Using maximum int ensity projections (MIP) together with multiplanar reformatting (MPR), acce ssory arteries were detected with a sensitivity/specificity of 100%/98%. De pending on diagnostic experience, exclusive evaluation of MIP yielded a sen sitivity/specificity of 67-100%/95-100%. Using MIP/MPR, venous depiction wa s good in 80%, with MIP solely in 30-40%. At least the proximal third of th e ureter was visible in 67%. Conclusion: MPR/MIP evaluation of two-phase, c ontrast-enhanced MRA provides an excellent depiction of renal vessel anatom y for presurgical evaluation of renal transplant donors. Exclusive MIP asse ssment is less reliable and depends strongly on the examiner's experience. For sufficient visualization of the ureters, either additional measurements or low-dose diuretic injection have to performed.