[Imaging of the kidney and the urinary tract].

Radiologic imaging is very important for urologic diagnostics. Acute flank pain is frequently caused by an obstructive ureteral stone which is diagnosed by native computed tomography (CT) or alternatively by intravenous urography (IVU). In suspicion of a parenchymal renal tumor a CT is performed. Tumors of the renal pelvis or the ureter are diagnosed by IVU followed by a retrograde pyelography to achieve a selective local wash-cytology. A CT or MRI of the abdomen are necessary for staging (local lymphnodes or systemic metastasis?) and to show also the local tumor extension. Exophytic and invasive processes of the bladder can be seen by CT or by ultrasound, but if a bladder tumor is suspected a cystoscopy is mandatory as primary diagnostic tool and can't be replaced by any imaging modalities. Cystography shows bladder injuries and serves together with a voiding image to identify vesicoureteral reflux. In strictures and injuries of the urethra a retro- and antegrade urethrography should be performed.