Value of intravoxel incoherent motion diffusion-weighted imaging in differentiating the pathological grade of clear cell renal cell carcinoma

We explored the value of intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) in differentiating the pathological grades of clear cell renal cell carcinoma (ccRCC). Preoperative IVIM-DWI data from 42 patients with ccRCC were prospectively analyzed. IVIM-DWI parameters (apparent diffusion coefficient [ADC], pure diffusion coefficient [D], pseudo-diffusion coefficient [D*] and perfusion fraction [f]) were compared between the low Fuhrman grade (grades I and II) and high Fuhrman grade (grades III and IV) ccRCC groups. The high-grade ccRCC group exhibited significantly lower ADC ([1.10 +/- 0.58] x 10(-3) mm(2)/s vs. [1.62 +/- 0.24] x 10(-3) mm(2)/s, P = 0.003), D ([1.40 +/- 0.20] x 10(-3) mm(2)/s vs. [1.73 +/- 0.18] x 10(-3) mm(2)/s, P<0.001) and f (0.15 +/- 0.09 vs. 0.27 +/- 0.08, P<0.001) values compared with the low-grade group. There was no significant difference in the D* values between the two groups ([72.18 +/- 90.28] x 10(-3) mm(2)/s vs. [109.46 +/- 129.07] x 10(-3) mm(2)/s, P = 0.772). The optimal cut-off values (area under the curve, sensitivity and specificity) for distinguishing low-and high-grade ccRCCs were as follows: ADC = 1.14 x 10(-3) mm(2)/s (0.768, 95.2% and 66.7%), D = 1.64 x 10(-3) mm(2)/s (0.931, 81.0% and 100.0%), and f = 0.18 (0.829, 85.7% and 66.7%). IVIM-DWI may be helpful in differentiating the Fuhrman grades of ccRCC.