A renal ultrasound is a good first step. Many benign renal masses are simple cysts. In many cases the evaluation of the kidneys is finished at this point if there is no hematuria. If the renal mass is not a simple cyst or there is unexplained hematuria, the appropriate follow-up examination is a CT scan of the kidneys before and after IV contrast with renal protocol. Oral contrast is not required. CT reveals the characteristics of the renal mass as well as surrounding lymph node sites, the IVC, and the remainder of the abdomen. Cystoscopy or retrograde pyelography may ultimately be required in cases of unresolved hematuria in order to definitively evaluate the ureters and bladder. A NM renal scan may be a useful adjunct if nephrectomy is considered, since it can quantify overall renal function and determine how much function is present in the potentially resected kidney; this may occasionally indicate that partial nephrectomy or wedge resection is preferable to total nephrectomy.