Imaging of renal cell carcinoma with gadolinium-enhanced magnetic resonance: radiological and pathological study.

The use of gadolinium-DTPA enhanced MR imaging (Gd-MR) in detecting and staging of large and small renal neoplasm was investigated in 61 patients with 66 renal cell carcinoma confirmed at surgery. The purpose of the study was also to evaluate the signal intensity of the lesions and to correlate the contrast-enhanced pattern to the pathological components and architecture of the surgical specimens. Forty-four tumors were larger than 3 cm and 22 lesions were smaller than 3 cm. Unenhanced MRI detected all large lesions (44/44) and 63% (14/22) of small lesions, while Gd-MRI detected all large and small neoplasms (100%). The overall staging accuracy was 79 and 87% for plain MRI and Gd-MRI, respectively, but both modalities led to an overstaging of the disease. Enhanced MRI was an excellent staging modality for the evaluation of tumor vascular extension and tumor spread to adjacent structures. The most frequent Gd-MRI pattern of small RCC was hyperintensity, while large lesions were mostly hypointense. The presence of fibrohyaline components seemed responsible for the hyperintense pattern. No specific contrast-enhanced MRI pattern was observed according to the tumor architecture (alveolar, tubular or papillar) of noncystic lesions. On the contrary, cystic lesion appeared as an area of low signal intensity and the use of contrast media improved detection and characterization. The inhomogeneous signal intensity increased the detectability of the lesion.