Computed tomography of the kidney.

Computed tomography is an extremely accurate method of obtaining more definitive diagnostic information about a renal mass discovered on a urogram. Benign renal cysts are readily distinguished from solid renal neoplasms, and CT is often valuable in characterizing possible juxtarenal masses. The cause of a nonfunctioning kidney(s) on a urogram can often be discerned, and hydronephrosis is easily detected.