HELICAL AND ELECTRON-BEAM CT SCANNING IN THE EVALUATION OF RENAL-VEININVOLVEMENT IN PATIENTS WITH RENAL-CELL CARCINOMA

Purpose: The purpose of this study was to assess helical and electron beam CT scanning in the evaluation of renal vein involvement in patien ts with renal cell carcinoma (RCC). Method: Seventy-three patients wit h 76 pathologically proven RCC who underwent surgical resection or aut opsy were evaluated for the accuracy of helical and electron beam CT s canning in the detection of renal vein tumor thrombus in patients with RCC. Patients were entered into the study only if they were scanned o n either electron beam or helical CT scanners with intravenous contras t medium enhancement. The tumors involved the right kidney in 38 cases and the left kidney in 38 cases, with tumor size ranging from 1.5 to 19 cm (mean 7 cm). The pathologic grade of the tumor was Grade I in 21 , Grade II in 37, Grade III in 15, and Grade IV in 3 patients. Results : The accuracy of preoperative CT evaluation of the renal vein for pre sence or absence of tumor thrombus was 96%. The negative predictive va lue was 97% and the positive predictive value was 92%. Sensitivity was 85% with a specificity of 98%. In two cases we were unable to detect small intrarenal venous thrombus, although this was present on a micro scopic level and did not affect surgical resection. A single false-pos itive CT result occurred secondary to un-opacified blood flow from a c apsular vein into the affected renal vein, resulting in a small flow v oid on CT. Conclusion: The data show that preoperative staging of the renal vein in the patients with RCC is effectively provided with helic al and electron beam CT scanning.