Staging and differential diagnosis of renal cell carcinoma: a comparison of magnetic resonance imaging (MRI) and computed tomography (CT)

The usefulness of magnetic resonance imaging (MRI) was compared with that of computed tomography (CT). Twenty-nine patients with renal cell carcinoma, 3 with angiomyolipomas and 1 with renal pelvic cancer, were examined by both MRI and CT. MRI and CT showed similar results in staging cases of renal cell carcinoma. However, MRI may be more sensitive in detecting the venous extension, metastatic adenopathy, and adjacent organ invasion. In predicting the involvement of perinephric fat, however, MRI is only marginally superior to CT. To demonstrate the usefulness of MRI in differentiating renal cell carcinoma from other renal tumors, the density of renal tumor and that of the psoas muscle were determined using a densitiometer, and the percent (%) contrast (the intensity of the renal tumor/the intensity of the psoas muscle X 100) was calculated. In most patients with clear cell type renal carcinoma, the % contrast value in the T1 weighted images was about 100. In the T2 weighted images, the maximum value of the % contrast value was 50 or less in most patients. In one patient with spindle cell type (sarcomatoid type) carcinoma, the % contrast value was 109 in the T1 weighted images, but was 65-85, at most, in the T2 weighted images. In patients with renal angiomyolipomas, the % contrast values were calculated exclusive of the fatty components. The % contrast value of the T1 weighted images was 50 or less in all 3 patients, and that of the T2 weighted images was 50 or more in 2 patients and 21-38 in the others.(ABSTRACT TRUNCATED AT 250 WORDS)