Role of gadolinium (Gd-DTPA) in the staging of renal carcinoma using magnetic resonance. Comparative evaluation with computerized tomography and magnetic resonance without contrast media

The correct staging of renal neoplasms is critical for both prognosis and subsequent treatment planning. This study was aimed at evaluating the accuracy of contrast-enhanced CT, of plain MR and of contrast-enhanced MR in the staging of renal cell carcinomas (RCC). Forty-four consecutive patients with renal masses were evaluated. All of them underwent plain and enhanced CT and 0.5 T plain and Gadolinium-enhanced MR. T1, T2 and Gd-DTPA T1-weighted MR sequences were acquired (500/20; 2000/100). The diagnostic studies were prospectively and separately interpreted by three radiologists. Imaging findings were then correlated with pathologic findings in all cases. The Robson Staging System was used for pathologic classification. The anatomical staging was correctly performed by CT and MR in 36/44 patients (82%) and by Gd-MR in 39/44 (89%). Seven stage-I and 1 stage-IIIC patients were overstaged by enhanced CT and by plain MR (3 patients to stage II and 5 to stage IV A); 5 stage-I patients were over-staged by Gd-MR (4 patients to stage II and 1 to stage IV A). In four cases, in which CT and MR misdiagnosed stage IV A, Gd-MR correctly identified the lack of adjacent organ infiltration. Perinephric spread, venous invasion, metastatic lymphadenopathy and distant metastases were correctly evaluated by the three imaging modalities. Our results suggest that Gd-DTPA could be useful in identifying direct tumor spread to adjacent organs, because of the different enhancement between the cancer and the other tissues.