Diffusion kurtosis versus diffusion-weighted MRI in differentiating clear cell renal cell carcinoma and renal angiomyolipoma with minimal fat: a comparative study

Abstract

Background Apparent diffusion coefficient(ADC) assessment has also shown benefit in distinguishing renal tumor types, however, there is always concern that the ADC obtained from conventional monoexponential diffusion-weighted imaging (DWI) could not accurately reflect the real diffusivity, because of the influence of microcirculation. The aim of the current study was to produce a quantitative comparison of the potential of various diffusion parameters obtained from DWI and diffusion kurtosis imaging(DKI) in differentiating clear cell renal cell carcinoma (ccRCC) and renal angiomyolipoma with minimal fat(RAMF). Methods Sixty-eight patients with ccRCC and 18 patients with RAMF were retrospectively studied. For DKI and ADC, respiratory triggered echo-planar imaging sequences were acquired in axial plane (three b-values: 0, 1000, 2000s/mm2) and (one b-value: 2000s/mm2). Mean Diffusivity (MD), fractional Anisotropy (FA), mean kurtosis (MK), kurtosis anisotropy (KA), radial kurtosis (RK) and apparent diffusion coefficient (ADC) were performed. The diagnostic efficacy of various diffusion parameters for predicting ccRCC and RAMF was compared. Results The ADC and MD values of ccRCCs were higher than those of RAMFs (p < 0.05), while comparable FA, MK and KA values were found between ccRCCs and RAMFs (p > 0.05). Moreover, the RK values of RAMFs were higher than those of ccRCCs (p < 0.05). ROC curve analyses showed that MD values had the highest diagnostic efficacy in differentiating ccRCCs from RAMFs. For pairwise comparisons of ROC curves and diagnostic efficacy, ADC was worse than DKI analysis (p < 0.05). Conclusion DKI analysis performs better than ADC analysis in differentiating ccRCC and RAMF.