[Imaging tumor extension of renal cell carcinomas with magnetic resonance tomography. Improved tumor-tissue contrast with Gd-DTPA-assisted spin-echo sequences and simultaneous fat suppression].

PURPOSE

To evaluate the use of contrast-enhanced T1-weighted images with fat suppression (T1FS) to improve the contrast-to-noise ratio of renal cancer and renal parenchyma as well as perirenal fat.

METHODS

25 patients with histologically proven unilateral renal cancer after nephrectomy were examined before surgery. In addition to plane and contrast-enhanced T1-weighted as well as T2-weighted spin-echo images, all patients had T1 FS immediately after administration of Gd-DTPA in two planes. The contrast-to-noise ratio was calculated using circular regions-of-interest which outlined the tumor, the renal parenchyma, pyelon, and the perirenal fat.

RESULTS

T1 FS significantly improved the contrast-to-noise ratio of renal cancer and renal parenchyma compared to all conventional spinecho sequences (p < 0.001; Wilcoxon-Test). Compared to contrast-enhanced T1-weighted images without fat-suppression T1 FS yielded a higher CNR of the tumor, the perirenal fat and the pyelon. Another advantage was the absence of the chemical-shift artifact which is mostly pronounced in T2-weighted images and a reduced number of observed artifacts due to breathing.

CONCLUSION

T1 FS should replace conventional contrast-enhanced T1-weighted spin-echo images in the work-up of renal cancer using MRI.