Abstract

Renal cell carcinoma is the most common primary tumor of the kidney, with more than 30,000 new cases diagnosed in the United States each year. With the widespread use of cross-sectional imaging, many tumors are detected incidentally. Single- and multidetector computed tomography (CT) have helped refine the diagnostic work-up of renal masses by allowing image acquisition in various phases of renal enhancement after intravenous administration of a single bolus of contrast material. The scanning protocol should include unenhanced CT followed by imaging during the corticomedullary and nephrographic phases of enhancement. The nephrographic phase is the most sensitive for tumoral detection, while the corticomedullary phase is essential for imaging the renal veins for possible tumoral extension and the parenchymal organs for potential metastases. Knowledge of the tumoral stage at the time of diagnosis is essential for prognosis and surgical planning. The accuracy of CT for staging has been reported to reach 91%, with most staging errors related to the diagnosis of perinephric extension of tumor. Three-dimensional CT provides the urologist with an interactive road map of the relationships among the tumor, the major vessels, and the collecting system. This information is particularly critical if the tumor extends into the inferior vena cava and if nephron-sparing surgery is being planned.