Figure 10e. Vascular impression on the left renal pelvis in a 25-year-old woman. (a) Intravenous urogram demonstrates a nonspecific filling defect in the left renal pelvis (arrows). (b) Three-dimensional VR image (posterior projection) demonstrates the filling defect (arrows). (c, d) Sagittal reformatted image (c) and axial excretory-phase CT scan (d) demonstrate an extrinsic impression on the posterior aspect of the renal pelvis (arrows). (e) Axial nephrographic-phase CT scan demonstrates a branch of the left renal vein (arrowheads) that is causing the extrinsic impression on the renal pelvis.