title: Magnetic resonance-based total liver volume and magnetic resonance-diffusion weighted imaging for staging liver fibrosis in mini-pigs.
abstract: OBJECTIVE
  To determine whether and how magnetic resonance imaging (MRI)-based total liver volume (TLV) and diffusion weighted imaging (DWI) could predict liver fibrosis.
  
  
  METHODS
  Sixteen experimental mature mini-pigs (6 males, 10 females), weighing between 20.0 and 24.0 kg were prospectively used to model liver fibrosis induced by intraperitoneal injection of 40% CCl(4) dissolved in fat emulsion twice a week for 16 wk, and by feeding 40% CCl(4) mixed with maize flour twice daily for the subsequent 5 wk. All the survival animals underwent percutaneous liver biopsy and DWI using b = 300, 500 and 800 s/mm(2) followed by abdominal gadolinium-enhanced MRI at the 0, 5th, 9th, 16th and 21st weekend after beginning of the modeling. TLV was obtained on enhanced MRI, and apparent diffusion coefficient (ADC) was obtained on DWI. Hepatic tissue specimens were stained with hematoxylin and Masson's trichrome staining for staging liver fibrosis. Pathological specimens were scored using the human METAVIR classification system. Statistical analyses were performed to determine whether and how the TLV and ADC could be used to predict the stage of liver fibrosis.
  
  
  RESULTS
  TLV increased from stage 0 to 2 and decreased from stage 3 (r = 0.211; P < 0.001). There was a difference in TLV between stage 0-1 and 2-4 (P = 0.03) whereas no difference between stage 0-2 and 3-4 (P = 0.71). TLV could predict stage ≥ 2 [area under receiver operating characteristic curve (AUC) = 0.682]. There was a decrease in ADC values with increasing stage of fibrosis for b = 300, 500 and 800 s/mm(2) (r = -0.418, -0.535 and -0.622, respectively; all P < 0.001). Differences were found between stage 0-1 and 2-4 in ADC values for b = 300, 500 and 800 s/mm(2), and between stage 0-2 and 3-4 for b = 500 or 800 s/mm(2) (all P < 0.05). For predicting stage ≥ 2 and ≥ 3, AUC was 0.803 and 0.847 for b = 500 s/mm(2), and 0.848 and 0.887 for b = 800 s/mm(2), respectively.
  
  
  CONCLUSIONS
  ADC for b = 500 or 800 s/mm(2) could be better than TLV and ADC for b = 300 s/mm(2) to predict fibrosis stage ≥ 2 or ≥ 3.
authors: Sichuan Key Laboratory of Medical Imaging, Department of Radiology, Affiliated Hospital of North Sichuan Medical College, Nanchong 637000, Sichuan Province, China.
authors: Hang
authors: H
authors: Li
authors: Tian-Wu
authors: TW
authors: Chen
authors: Xiao-Li
authors: XL
authors: Chen
authors: Xiao-Ming
authors: XM
authors: Zhang
authors: Zhen-Lin
authors: ZL
authors: Li
authors: Nan-Lin
authors: NL
authors: Zeng
authors: Li
authors: L
authors: Zhou
authors: Li-Ying
authors: LY
authors: Wang
authors: Hong-Jie
authors: HJ
authors: Tang
authors: Chun-Ping
authors: CP
authors: Li
authors: Li
authors: L
authors: Li
authors: Xian-Yong
authors: XY
authors: Xie
mesh_terms: D000818:Animals; D019540:Area Under Curve; D002251:Carbon Tetrachloride; D003287:Contrast Media / Q000494:pharmacology; D004058:Diffusion; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D004195:Disease Models, Animal; D005260:Female; D005682:Gadolinium / Q000494:pharmacology; D008099:Liver / Q000473:pathology*; D008103:Liver Cirrhosis / Q000473:pathology*; D008297:Male; D015233:Models, Statistical; D009929:Organ Size; D012372:ROC Curve; D013552:Swine; D013556:Swine, Miniature
chemical_list: D003287:Contrast Media; D005682:Gadolinium; D002251:Carbon Tetrachloride
keywords: Apparent diffusion coefficient; Liver fibrosis; Magnetic resonance imaging; Stage; Total liver volume