title: IVIM Diffusion-weighted Imaging of the Liver at 3.0T: Comparison with 1.5T.
abstract: OBJECTIVE
  To compare intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) of the liver between 1.5T and 3.0 T in terms of parameter quantification and inter-platform reproducibility.
  
  
  METHODS
  In this IRB approved prospective study, 19 subjects (17 patients with chronic liver disease and 2 healthy volunteers) underwent two repeat scans at 1.5T and 3.0T. Each scan included IVIM DWI using 16 b values from 0 to 800 s/mm2. A single observer measured IVIM parameters for each platform and estimated signal to noise ratio (eSNR) at b0, 200, 400 and 800 s/mm2. Wilcoxon paired tests were used to compare liver eSNR and IVIM parameters. Inter-platform reproducibility was assessed by calculating within-subject coefficient of variation (CV) and Bland-Altman limits of agreement. An ice water phantom was used to test ADC variability between the two MRI systems.
  
  
  RESULTS
  The mean invitro difference in ADC between the two platforms was 6.8%. eSNR was significantly higher at 3.0T for all selected b values (p=0.006-0.020), except for b0 (p=0.239). Liver IVIM parameters were significantly different between 1.5T and 3.0T (p=0.005-0.044), except for ADC (p=0.748). The inter-platform reproducibility of true diffusion coefficient (D) and ADC were good, with mean CV of 10.9% and 11.1%, respectively. Perfusion fraction (PF) and pseudodiffusion coefficient (D*) showed more limited inter-platform reproducibility (mean CV of 22.6% for PF and 46.9% for D*).
  
  
  CONCLUSIONS
  Liver D and ADC values showed good reproducibility between 1.5T and 3.0T platforms; while there was more variability in PF, and large variability in D* parameters between the two platforms. These findings may have implications for drug trials assessing the role of IVIM DWI in tumor response and liver fibrosis.
authors.affiliation: Department of Radiology/Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, NY 10029 USA.
authors.forename: Yong
authors.initials: Y
authors.lastname: Cui
authors.affiliation: Department of Radiology/Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, NY 10029 USA.
authors.forename: Hadrien
authors.initials: H
authors.lastname: Dyvorne
authors.affiliation: Department of Radiology/Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, NY 10029 USA.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Besa
authors.affiliation: Department of Radiology/Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, NY 10029 USA.
authors.forename: Nancy
authors.initials: N
authors.lastname: Cooper
authors.affiliation: Department of Radiology/Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, NY 10029 USA.
authors.forename: Bachir
authors.initials: B
authors.lastname: Taouli
keywords: 3.0T; diffusion-weighted imaging; intravoxel incoherent motion; liver; reproducibility