title: Hepatocellular carcinoma: short-term reproducibility of apparent diffusion coefficient and intravoxel incoherent motion parameters at 3.0T.
abstract: OBJECTIVE
  To evaluate short-term test-retest and interobserver reproducibility of IVIM (intravoxel incoherent motion) diffusion parameters and ADC (apparent diffusion coefficient) of hepatocellular carcinoma (HCC) and liver parenchyma at 3.0T.
  
  
  METHODS
  In this prospective Institutional Review Board (IRB)-approved study, 11 patients were scanned twice using a free-breathing single-shot echo-planar-imaging, diffusion-weighted imaging (DWI) sequence using 4 b values (b = 0, 50, 500, 1000 s/mm(2)) and IVIM DWI using 16 b values (0-800 s/mm(2)) at 3.0T. IVIM parameters (D: true diffusion coefficient, D*: pseudodiffusion coefficient, PF: perfusion fraction) and ADC (using 4 b and 16 b) were calculated. Short-term test-retest and interobserver reproducibility of IVIM parameters and ADC were assessed by measuring correlation coefficient, coefficient of variation (CV), and Bland-Altman limits of agreements (BA-LA).
  
  
  RESULTS
  Fifteen HCCs were assessed in 10 patients. Reproducibility of IVIM metrics in HCC was poor for D* and PF (mean CV 60.6% and 37.3%, BA-LA: -161.6% to 135.3% and -66.2% to 101.0%, for D* and PF, respectively), good for D and ADC (CV 19.7% and <16%, BA-LA -57.4% to 36.3% and -38.2 to 34.1%, for D and ADC, respectively). Interobserver reproducibility was on the same order of test-retest reproducibility except for PF in HCC. Reproducibility of diffusion parameters was better in liver parenchyma compared to HCC.
  
  
  CONCLUSIONS
  Poor reproducibility of D*/PF and good reproducibility for D/ADC were observed in HCC and liver parenchyma. These findings may have implications for trials using DWI in HCC.
authors.affiliation: Department of Radiology/Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
authors.forename: Suguru
authors.initials: S
authors.lastname: Kakite
authors.forename: Hadrien
authors.initials: H
authors.lastname: Dyvorne
authors.forename: Cecilia
authors.initials: C
authors.lastname: Besa
authors.forename: Nancy
authors.initials: N
authors.lastname: Cooper
authors.forename: Marcelo
authors.initials: M
authors.lastname: Facciuto
authors.forename: Claudia
authors.initials: C
authors.lastname: Donnerhack
authors.forename: Bachir
authors.initials: B
authors.lastname: Taouli
mesh_terms: D000328:Adult; D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000175:diagnosis*; D003287:Contrast Media; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D017352:Echo-Planar Imaging / Q000379:methods*; D019786:Gadolinium DTPA; D006801:Humans; D007089:Image Enhancement; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008099:Liver / Q000473:pathology; D008113:Liver Neoplasms / Q000175:diagnosis*; D008297:Male; D008536:Meglumine / Q000031:analogs & derivatives; D008875:Middle Aged; D009038:Motion; D015588:Observer Variation; D009942:Organometallic Compounds; D011446:Prospective Studies; D015203:Reproducibility of Results
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C073590:gadolinium ethoxybenzyl DTPA; C064572:gadobenic acid; D008536:Meglumine; D019786:Gadolinium DTPA
keywords: diffusion; hepatocellular carcinoma; perfusion; reproducibility