The Study of Clear Cell Renal Cell Carcinoma with MR Diffusion Kurtosis Tensor Imaging and Its Histopathologic Correlation.

RATIONALE AND OBJECTIVES: The objective of this study was to compare the performance of diffusion kurtosis tensor imaging and diffusion-weighted imaging in the characterization of clear cell renal cell carcinoma (ccRCC) and their correlations with tumor histopathology.

MATERIALS AND METHODS: Ninety-one patients diagnosed with ccRCC who underwent diffusion kurtosis tensor imaging were included in this study. Fractional anisotropy, mean diffusivity, radial diffusivity, axial diffusivity, mean kurtosis (MK), radial kurtosis (Krad), and axial kurtosis (Kax) data were produced. A nuclear grade of 1-4 (G1-4) was assigned for each case based on the Fuhrman grading system, whereas tumor histopathology was characterized by the nuclear-to-cytoplasm ratio, the cell nuclei count, and the cell volume fraction.

RESULTS: All of the metric values except for Kax and fractional anisotropy could be used to discriminate G1 vs G3, G1 vs G4, G2 vs G3, and G2 vs G4, whereas MK and Kax could be used to discriminate G3 vs G4 (P <0.05). Moreover, the MK and Krad values exhibited better performance in differentiating G2 from G3 (P < 0.04 compared to the other metrics). The nuclear-to-cytoplasm ratio was positively correlated with the MK, Krad, and Kax values (P <0.001) and negatively correlated with the mean diffusivity, radial diffusivity, and axial diffusivity values (P <0.001), whereas the cell volume fraction and the cell nuclei count did not correlate with any metric examined.

CONCLUSION: The kurtosis metrics were superior to the diffusion metrics in grading ccRCC.