CT staging of renal carcinoma: a prospective comparison of three dynamic computed tomography techniques.

Three dynamic computed tomographic methods used for staging of renal carcinoma in 70 patients are described and compared. Twenty-eight patients were examined using incremental dynamic scanning across the kidneys whilst infusing contrast via an arm vein (technique 1). Eighteen patients were staged using a single location dynamic scan sequence at the level of the renal hilum followed by an incremental sequence during an infusion of contrast into the femoral vein (technique 2). Twenty-four patients were examined using a single location sequence at the level of the renal veins and a rapid bolus incremental dynamic technique (technique 3). Technique 1 correctly staged 20 patients (72%) with 4 patients (14%) understaged and 4 (14%) overstaged, technique 2 correctly staged 11 (61%) patients with 3 (17%) overstaged and 4 (22%) understaged and technique 3 staged 17 (71%) correctly with 3 (13%) understaged and 4 (17%) overstaged. The techniques using single location scanning were more accurate in demonstrating tumour involvement of the renal vein and inferior vena cava but were less accurate in assessing extracapsular spread. Technique 3 was the most accurate in the diagnosis of lymph-node involvement. As accurate pre-operative knowledge of vascular involvement by tumour is more important to the surgeon than the presence of extracapsular spread, the combined single location and incremental scan technique is advocated.