title: Evaluation of hepatic focal lesions using diffusion-weighted MR imaging: comparison of apparent diffusion coefficient and intravoxel incoherent motion-derived parameters.
abstract: OBJECTIVE
  To determine whether parameters obtained from intravoxel incoherent motion (IVIM)-diffusion-weighted imaging (DWI) using multiple b-values can improve characterization of common focal liver lesions (FLLs), compared with the apparent diffusion coefficient (ADCtotal ).
  
  
  METHODS
  Our Institutional Review Board approved this retrospective study and informed consent was waived. In all, 142 patients with 169 FLLs underwent liver magnetic resonance imaging (MRI) including IVIM-DWI with multiple b factors at 3.0T. ADCtotal and IVIM-DWI-derived parameters including true diffusion (Dt ), pseudodiffusion (Dp ), and perfusion fraction (f) were calculated for each lesion and compared using dedicated software.
  
  
  RESULTS
  Dt and ADCtotal were significantly lower in malignancies (0.95 ± 0.21, 1.14 ± 0.24, (×10(-3) mm(2) /sec)) than in benign FLLs (1.61 ± 0.34, 1.72 ± 0.37, (×10(-3) mm(2) /sec)). In the differential diagnosis of malignancies from benign lesions, Dt (Az value: 0.971) showed better diagnostic performance than ADCtotal (Az: 0.933) (P < 0.0005). Dt (Az: 0.961) also showed better diagnostic performance than ADCtotal (Az: 0.919) in differentiating hypervascular malignancies from benign hypervascular FLLs (P < 0.0005). In addition, Dp and f were significantly higher in hypervascular FLLs (35.74 ± 20.08 (×10(-3) mm(2) /sec), 28.14 ± 11.82 (%)) than hypovascular FLLs (21.87 ± 13.8 (×10(-3) mm(2) /sec), 12.2 ± 5.92 (%)) (P < 0.0001).
  
  
  CONCLUSIONS
  Dt provided better diagnostic performance than ADCtotal in differentiating benign from malignant lesions. Dp and f were significant parameters for diagnosing hypervascular FLLs.
authors: Department of Radiology, Seoul National University Hospital, Seoul, Korea.
authors: Jeong Hee
authors: JH
authors: Yoon
authors: Jeong Min
authors: JM
authors: Lee
authors: Mi Hye
authors: MH
authors: Yu
authors: Berthold
authors: B
authors: Kiefer
authors: Joon Koo
authors: JK
authors: Han
authors: Byung Ihn
authors: BI
authors: Choi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000465:Algorithms; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008099:Liver / Q000473:pathology*; D008113:Liver Neoplasms / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009038:Motion; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
keywords: diffusion-weighted imaging; focal liver lesion; intravoxel incoherent motion