Figure 16a. Complex vascular anatomy in a 31-year-old woman. The patient had undergone renal transplantation 9 years earlier and placement of a venous patch graft due to renal artery stenosis 4 years after transplantation. Anteroposterior (a) and oblique (b) volume-rendered MR angiograms demonstrate clear patency of the patch graft between the external iliac artery and the main transplant renal artery (arrow), thereby illustrating the usefulness of being able to view MR angiograms in any 3D projection.