Gadolinium-enhanced Breathhold Three-dimensional Time-of-Flight Renal MR Angiography in the Evaluation of Potential Renal Donors

Abstract

To evaluate the utility of gadolinium-enhanced three-dimensional (3D) time-of-flight (TOF) magnetic resonance angiography (MRA) of the renal arteries in the evaluation of potential renal donors. Fifty consecutive patients underwent gadolinium-enhanced 3D-TOF MRA of the renal arteries as part of their evaluation as possible renal donors. All imaging was performed on a 1.5-T system with use of a torso phased-array coil. Conventional T1-weighted axial spin-echo and T2-weighted axial fast spin-echo imaging was performed to evaluate the renal parenchyma. Coronal dynamic MRA was performed during bolus injection of 40 mL of gadolinium with use of a 3D-TOF sequence requiring a breathhold of approximately 30 seconds. Maximum-intensity-projection reconstructions were obtained of the renal arterial and venous anatomy. All studies were prospectively evaluated by a single radiologist experienced with body MRA. Intraoperative findings were used as the reference standard in 35 patients. To evaluate interobserver variability, each examination was evaluated for image quality, renal artery number, and anatomy by two radiologists experienced with MRA and blinded to the other's interpretations and surgical results. Ninety-eight percent of all MRAs were graded as diagnostic quality (Kappa value = 0.38; P < .05). Multiple renal arteries were identified in 29 (29%) of 100 kidneys. Four of 50 patients studied (8%) had renal parenchymal abnormalities identified with MR imaging. Sensitivity and specificity for accessory renal artery detection was 71% and 95%, respectively. Overall, accuracy for MRA in determining renal artery number was 90%. Gadolinium-enhanced breathhold 3D-TOF renal MRA is sufficient to assess the renal arteries in potential donors.