title: Evaluation of fibrosis and inflammation in diffuse liver diseases using intravoxel incoherent motion diffusion-weighted MR imaging.
abstract: The purpose of the study was to evaluate the role of intravoxel incoherent motion (IVIM) diffusion model for the assessment of liver fibrosis and inflammation in diffuse liver disorders, also considering the presence of liver steatosis and iron deposits.
  
  
  
  Seventy-four patients were included, with liver biopsy and a 3 Tesla abdominal magnetic resonance imaging examination, with an IVIM diffusion-weighted sequence (single-shot spin-echo echo-planar sequence, with gradient reversal fat suppression; 6 b-values: 0, 50, 200, 400, 600, and 800 s/mm2). Histological evaluation comprised the Ishak modified scale, for grading inflammation and fibrosis, plus steatosis and iron loading classification. The liver apparent diffusion coefficient (ADC) and IVIM parameters (D, D*, f) were calculated from the IVIM images. The relationship between IVIM parameters and histopathological scores were evaluated by ANOVA and Spearman correlation tests. A test-retest experiment assessed reproducibility and repeatability in 10 healthy volunteers and 10 randomly selected patient studies.
  
  
  
  ADC and f values were lower with higher fibrosis stages (p = 0.009, p = 0.006, respectively) and also with higher necro-inflammatory activity grades (p = 0.02, p = 0.017, respectively). Considered together, only fibrosis presented a significant effect on ADC and f measurements (p < 0.05), whereas inflammation had no significant effect (p > 0.05). A mild correlation was found between ADC and f with fibrosis (RS= -0.32 and RS= -0.38; p < 0.05) and inflammation (RS= -0.31 and RS= -0.32, p < 0.05; respectively). The AUROC for ADC and f measurements with the different dichotomizations between fibrosis or inflammation grades were only fair (0.670 to 0.749, p < 0.05). Neither D nor D* values were significantly different between liver fibrosis or inflammation grades. D measurements were significantly different across histologic grades of steatosis (p < 0.001) and iron overload (p < 0.001), whereas f measurements showed significant differences across histologic steatosis grades (p = 0.005). There was an excellent agreement between the different readers for ADC, f, and D.
  
  
  
  Although fibrosis presented a significant effect on ADC and f, IVIM measurements are not accurate enough to stage liver fibrosis or necro-inflammatory activity in diffuse liver diseases. D values were influenced by steatosis and iron overload.
authors.affiliation: Imaging Department, Centro Hospitalar do Porto, Largo Prof Abel Salazar, 4099-001, Porto, Portugal. mariamanuela.franca@gmail.com.
authors.forename: Manuela
authors.identifier: 0000-0003-1068-8577
authors.initials: M
authors.lastname: França
authors.affiliation: Radiology Department, Hospital Universitario y Politécnico La Fe and Biomedical Imaging Research Group (GIBI230), Valencia, Spain.
authors.forename: Luis
authors.initials: L
authors.lastname: Martí-Bonmatí
authors.affiliation: Radiology Department, Hospital Universitario y Politécnico La Fe and Biomedical Imaging Research Group (GIBI230), Valencia, Spain.
authors.forename: Ángel
authors.initials: Á
authors.lastname: Alberich-Bayarri
authors.affiliation: Population Studies Department, Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, Porto, Portugal.|Epidemiology Research Unit (EPI Unit), Institute of Public Health of the University of Porto, Porto, Portugal.
authors.forename: Pedro
authors.initials: P
authors.lastname: Oliveira
authors.affiliation: Pathology Department, Centro Hospitalar de S. João, Porto, Portugal.
authors.forename: Susana
authors.initials: S
authors.lastname: Guimaraes
authors.affiliation: Radiology Department, Centro Hospitalar do Porto, Porto, Portugal.
authors.forename: João
authors.initials: J
authors.lastname: Oliveira
authors.affiliation: Radiology Department, Centro Hospitalar do Porto, Porto, Portugal.
authors.forename: João
authors.initials: J
authors.lastname: Amorim
authors.affiliation: MR Clinical Science, Philips Healthcare, Madrid, Spain.
authors.forename: Javier Sanchez
authors.initials: JS
authors.lastname: Gonzalez
authors.affiliation: Pathology Department, Centro Hospitalar do Porto, Porto, Portugal.
authors.forename: José Ramón
authors.initials: JR
authors.lastname: Vizcaíno
authors.affiliation: Epidemiology Research Unit (EPI Unit), Institute of Public Health of the University of Porto, Porto, Portugal.|Liver and Pancreas Transplantation Unit and Medicine Department, Centro Hospitalar do Porto, Porto, Portugal.
authors.forename: Helena Pessegueiro
authors.initials: HP
authors.lastname: Miranda
mesh_terms: D000328:Adult; D001706:Biopsy; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005234:Fatty Liver / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007249:Inflammation / Q000000981:diagnostic imaging / Q000473:pathology; D019190:Iron Overload / Q000000981:diagnostic imaging* / Q000473:pathology; D008103:Liver Cirrhosis / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D015203:Reproducibility of Results