title: Diffusion tensor imaging of the median nerve at 3.0 T using different MR scanners: agreement of FA and ADC measurements.
abstract: OBJECTIVE
  To assess the agreement of fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values of the median nerve on 3.0 T MR scanners from different vendors.
  
  
  METHODS
  IRB approved study including 16 healthy volunteers (9 women; mean age 30.6 ± 5.3 years). Diffusion tensor imaging (DTI) of the dominant wrist was performed on three 3.0 T MR scanners (GE, Siemens, Philips) using similar imaging protocols and vendor-proprietary hard- and software. Intra-, inter-reader and inter-vendor agreements were assessed.
  
  
  RESULTS
  ICCs for intra-/inter-reader agreements ranged from 0.843-0.970/0.846-0.956 for FA, and 0.840-0.940/0.726-0.929 for ADC, respectively. ANOVA analysis identified significant differences for FA/ADC measurements among vendors (p < 0.001/p < 0.01, respectively). Overall mean values for FA were 0.63 (SD ± 0.1) and 0.999 × 10(-3)mm(2)/s (SD ± 0.134 × 10(-3)) for ADC. A significant negative measurement bias was found for FA values from the GE scanner (-0.05 and -0.07) and for ADC values from the Siemens scanner (-0.053 and -0.063 × 10(-3)mm(2)/s) as compared to the remainder vendors
  
  
  CONCLUSIONS
  FA and ADC values of the median nerve obtained on different 3.0 T MR scanners differ significantly, but are in comparison to the standard deviation of absolute values small enough to not have an impact on larger group studies or when substantial diffusion changes can be expected. However, caution is warranted in an individual patient when interpreting diffusion values from different scanner acquisitions.
authors.affiliation: Department of Radiology, University Hospital, Raemistrasse 100, Zurich, 8091, Switzerland. roman.guggenberger@usz.ch
authors.forename: Roman
authors.initials: R
authors.lastname: Guggenberger
authors.forename: Daniel
authors.initials: D
authors.lastname: Nanz
authors.forename: Lorenz
authors.initials: L
authors.lastname: Bussmann
authors.forename: Avneesh
authors.initials: A
authors.lastname: Chhabra
authors.forename: Michael A
authors.initials: MA
authors.lastname: Fischer
authors.forename: Jürg
authors.initials: J
authors.lastname: Hodler
authors.forename: Christian W A
authors.initials: CW
authors.lastname: Pfirrmann
authors.forename: Gustav
authors.initials: G
authors.lastname: Andreisek
mesh_terms: D000328:Adult; D056324:Diffusion Tensor Imaging / Q000295:instrumentation* / Q000379:methods*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000295:instrumentation* / Q000379:methods*; D008297:Male; D008475:Median Nerve / Q000033:anatomy & histology*; D015588:Observer Variation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
keywords: Diffusion tensor imaging; Magnetic resonance imaging; Median nerve; Peripheral neuropathy