Magnetic resonance diffusion kurtosis imaging in differential diagnosis of benign and malignant renal tumors

BackgroundBenign and malignant renal tumors share similar some imaging findings.MethodsSixty-six patients with clear cell renal cell carcinoma (CCRCC), 13 patients with renal angiomyolipoma with minimal fat (RAMF) and 7 patients with renal oncocytoma (RO) were examined. For diffusion kurtosis imaging (DKI), respiratory triggered echo-planar imaging sequences were acquired in axial plane (3 b-values: 0, 500, 1000s/mm(2)). Mean Diffusivity (MD), fractional Anisotropy (FA), mean kurtosis (MK), kurtosis anisotropy (KA) and radial kurtosis (RK) were performed.ResultsFor MD, a significant higher value was shown in CCRCC (3.080.23) than the rest renal tumors (2.93 +/- 0.30 for RO, 1.52 +/- 0.24 for AML, P<0.05). The MD values were higher for RO than for AML (2.930.30 vs.1.52 +/- 0.24, P<0.05), while comparable MD values were found between CCRCC and RO (3.080.23 vs. 2.93 +/- 0.30, P>0.05). For MK, KA and RK, a significant higher value was shown in AML (1.32 +/- 0.16, 1.42 +/- 0.23, 1.41 +/- 0.29) than CCRCC (0.43 +/- 0.08, 0.57 +/- 0.16, 0.37 +/- 0.11) and RO (0.81 +/- 0.08, 0.86 +/- 0.16, 0.69 +/- 0.08) (P<0.05). The MK, KA and RK values were higher for RO than for CCRCC (0.810.08 vs. 0.43 +/- 0.08, 0.86 +/- 0.16 vs. 0.57 +/- 0.16, 0.69 +/- 0.08 vs. 0.37 +/- 0.11, P<0.05). Using MD values of 2.86 as the threshold value for differentiating CCRCC from RO and AML, the best result obtained had a sensitivity of 76.1%, specificity of 72.6%. Using MK, KA and RK values of 1.19,1.13 and 1.11 as the threshold value for differentiating AML from CCRCC and RO, the best result obtained had a sensitivity of 91.2, 86.7, 82.1%, and specificity of 86.7, 83.2, 72.8%.Conclusion DKI can be used as another noninvasive biomarker for benign and malignant renal tumors' differential diagnosis.

Automated summary

Diffusion kurtosis imaging (DKI) can serve as another noninvasive biomarker for the differential diagnosis of benign and malignant renal tumors. By comparing the values of MD, MK, KA, and RK, different types of renal tumors can be effectively distinguished.