title: [Application of diffusion-weighted intravoxel incoherent motion imaging in diagnosis of renal cell carcinoma subtypes].
abstract: OBJECTIVE
  To evaluate the value of parameters derived from intravoxel incoherent motion diffusion-weighted magnetic resonance imaging in differentiating histopathological subtypes of renal cell carcinoma (RCC).
  
  
  METHODS
  Between May 2014 and December 2015, a total of 69 patients who were surgically and pathologically diagnosed as renal cell carcinoma were recruited for the study. We examined 61 clear cell RCC (ccRCC), and 8 non-clear cell carcinoma (non-ccRCC, including 7 chromophobe RCC and 1 papillary RCC). All the ccRCC were divided into well differentiated group (n=46), moderately differentiated group (n=8), and poorly differentiated group (n=7). In addition to routine renal magnetic resonance imaging examination performed on a 3.0-Tesla MR system, all patients were imaged with axial intravoxel incoherent motion diffusion-weighted imaging. Using biexponential model, we calculated the diffusion coefficient (D), pseudodiffusion coefficient (D(*)), and perfusion fraction (f).
  
  
  RESULTS
  The D and f values of the ccRCC were higher (each P<0.05) than that for non-ccRCC [D (1.29±0.30)×10(-3)mm(2)/s, D(*) (42.92±20.21)×10(-3)mm(2)/s, and f (35.71±6.61)% versus D (0.78±0.23)×10(-3)mm(2)/s, D(*) (32.60±11.33)×10(-3)mm(2)/s, and f (21.52±8.44)% ]. In the well differentiated group of ccRCC, we found D of (1.36±0.29)×10(-3)mm(2)/s, D(*) (38.39±18.51)×10(-3)mm(2)/s, and f (36.40±6.96)%. The D, D(*,) f values of moderately differentiated lesions were (1.10±0.24)×10(-3)mm(2)/s, (59.90±20.23)×10(-3) mm(2)/s, and (32.88±4.02)%, respectively, those of the poorly differentiated group were (1.03±0.16)×10(-3)mm(2)/s, (53.28±18.74)×10(-3)mm(2)/s, and (34.42±6.21)%. The well differentiated group of ccRCC showed a higher D value than the moderately differentiated and poorly differentiated groups (each P<0.05). D(*) values were significantly lower for the well differentiated group than for the moderately differentiated group (P<0.05). The sensitivity and specificity of D values were 90.2% and 87.5% when focusing on the differentiation of ccRCC. For the diagnosis of ccRCC, the sensitivity and specificity of f values were 98.4% and 75.0%, respectively.
  
  
  CONCLUSIONS
  IVIM-DWI can provide certain reliable value in evaluating pathological subtype and differentiation degree of renal cell carcinomas. D and f values are useful to distinguish ccRCC from non-ccRCC. D value is also promising for estimating the differentiation degree of ccRCC, and to indicate the biological behavior of RCC.
authors.affiliation: Department of Diagnostic Imaging, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China.
authors.forename: X Y
authors.initials: XY
authors.lastname: Cong
authors.affiliation: Department of Diagnostic Imaging, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Department of Diagnostic Imaging, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China.
authors.forename: J
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Diagnostic Imaging, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China.
authors.forename: X D
authors.initials: XD
authors.lastname: Yu
authors.affiliation: Department of Diagnostic Imaging, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China.
authors.forename: F
authors.initials: F
authors.lastname: Ye
authors.affiliation: Department of Diagnostic Imaging, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China.
authors.forename: W J
authors.initials: WJ
authors.lastname: Yu
authors.affiliation: Department of Diagnostic Imaging, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China.
authors.forename: M M
authors.initials: MM
authors.lastname: Zhang
authors.affiliation: Department of Diagnostic Imaging, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China.
authors.forename: H
authors.initials: H
authors.lastname: Ouyang
authors.affiliation: Department of Diagnostic Imaging, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China.
authors.forename: X M
authors.initials: XM
authors.lastname: Zhao
mesh_terms: D002292:Carcinoma, Renal Cell / Q000000981:diagnostic imaging*; D038524:Diffusion Magnetic Resonance Imaging; D006801:Humans; D009038:Motion; D012680:Sensitivity and Specificity