title: Intravoxel incoherent motion MRI for liver fibrosis assessment: a pilot study.
abstract: BACKGROUND
  There has been a growing need for an imaging method for the accurate diagnosis and staging of liver fibrosis as a non-invasive alternative to liver biopsy.
  
  
  OBJECTIVE
  To evaluate the feasibility of intra-voxel incoherent motion (IVIM) imaging for classifying the severity of liver fibrosis.
  
  
  METHODS
  Fifty-seven patients who underwent navigator-triggered, diffusion-weighted imaging (DWI) of the liver on a 1.5-T system using nine b-values and had a reliable reference standard for the diagnosis of liver fibrosis (histopathologic findings [n = 27] or clinical findings for normal [n = 18] or cirrhotic liver [n = 12]), were included in our study. Liver apparent diffusion coefficient (ADC), pure diffusion (Dslow), perfusion fraction (f), and perfusion-related diffusion (Dfast), and the product f · Dfast were compared with the liver fibrosis stages (F). The accuracies of these parameters in diagnosing severe liver fibrosis (F ≥3) were evaluated using the receiver-operating characteristic (ROC) curve analysis.
  
  
  RESULTS
  The liver fibrosis stages had the strongest negative correlation with f · Dfast (ρ = -0.52). All of the parameters, except for Dslow, were significantly lower in patients with F ≥3 than in those with F ≤2 (P ≤ 0.001). The area under the ROC curve for diagnosing severe fibrosis was the largest for f · Dfast (0.844) with an overall accuracy of 79.0% (45/57) at the optimal cutoff value and followed by f (0.834), Dfast (0.773), ADC (0.762), and Dslow (0.656).
  
  
  CONCLUSIONS
  IVIM imaging is a promising method for classifying the severity of liver fibrosis, with the product f · Dfast being the most accurate parameter.
authors.affiliation: Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea.
authors.forename: Sae Rom
authors.initials: SR
authors.lastname: Chung
authors.affiliation: Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea seungsoolee@amc.seoul.kr.
authors.forename: Seung Soo
authors.initials: SS
authors.lastname: Lee
authors.affiliation: Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea.
authors.forename: Namkug
authors.initials: N
authors.lastname: Kim
authors.affiliation: Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea.
authors.forename: Eun Sil
authors.initials: ES
authors.lastname: Yu
authors.affiliation: Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea Current address: Georgia Institute of Technology, North Avenue, Atlanta, GA, USA.
authors.forename: Eunki
authors.initials: E
authors.lastname: Kim
authors.affiliation: Siemens AG, Healthcare, Oncology Applications Development, Erlangen, Germany.
authors.forename: Bernd
authors.initials: B
authors.lastname: Kühn
authors.affiliation: Siemens Healthcare Korea, Seoul, Republic of Korea.
authors.forename: In Seong
authors.initials: IS
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008099:Liver / Q000473:pathology; D008103:Liver Cirrhosis / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009038:Motion; D010865:Pilot Projects; D012372:ROC Curve; D015203:Reproducibility of Results; D012720:Severity of Illness Index
keywords: Intra-voxel incoherent motion; diffusion-weighted imaging; fibrosis; liver; magnetic resonance imaging; quantitative image analysis