MR angiography after renal revascularization: Spectrum of expected anatomic results and postintervention complications

The use of magnetic resonance (MR) angiography in screening for renal arter y stenosis has been extensively evaluated. However, the MR angiographic fin dings after renal artery revascularization are not as well characterized. T he renal artery and parenchyma can be evaluated after revascularization wit h a comprehensive MR imaging protocol that includes T1- and T2-weighted spi n-echo sequences, three-dimensional (3D) gadolinium-enhanced MR angiography , and 3D phase-contrast MR angiography, Because surgical techniques for rev ascularization vary, knowledge of the surgical procedure is necessary to en sure inclusion of the pertinent anatomy at 3D gadolinium-enhanced MR angiog raphy and to define appropriate 3D phase-contrast MR angiography volumes. T he 3D gadolinium-enhanced MR angiography volume can be manipulated to view relevant vascular anatomy at the optimal obliquity and section thickness. T his protocol allows robust, noninvasive evaluation of the expected arterial anatomy after revascularization, including renal artery endarterectomy, ao rtorenal bypass grafts, and extraanatomic reconstructions. In cases of susp ected postrevascularization complications, gadolinium-enhanced MR angiograp hy is useful because of its lack of nephrotoxicity and radiation exposure. Immediate complications of renal revascularization include renal artery thr ombosis, renal infarction, and perinephric hemorrhage, Long-term complicati ons include aneurysms of bypass grafts and recurrent stenosis of the renal artery.