title: Development of a diffusion-weighted MRI protocol for multicentre abdominal imaging and evaluation of the effects of fasting on measurement of apparent diffusion coefficients (ADCs) in healthy liver.
abstract: OBJECTIVE
  To assess the effect of fasting and eating on estimates of apparent diffusion coefficient (ADC) in the livers of healthy volunteers using a diffusion-weighted MRI protocol with b-values of 100, 500 and 900 s mm(-2) in a multicentre study at 1.5 T.
  
  
  METHODS
  20 volunteers were scanned using 4 clinical 1.5-T MR scanners. Volunteers were scanned after fasting for at least 4 h and after eating a meal; the scans were repeated on a subsequent day. Median ADC estimates were calculated from all pixels in three slices near the centre of the liver. Analysis of variance (ANOVA) was used to assess the difference between ADC estimates in fasted and non-fasted states and between ADC estimates on different days.
  
  
  RESULTS
  ANOVA showed no difference between ADC estimates in fasted and non-fasted states (p = 0.8) nor between ADC estimates on different days (p = 0.8). The repeatability of the measurements was good, with coefficients of variation of 5.1% and 4.6% in fasted and non-fasted states, respectively.
  
  
  CONCLUSIONS
  There was no significant difference in ADC estimates between fasted and non-fasted measurements, indicating that the perfusion sensitivity of ADC estimates obtained from b-values of 100, 500 and 900 s mm(-2) is sufficiently low that changes in blood flow in the liver after eating are undetectable beyond the variability in the measurements.
  
  
  CONCLUSIONS
  Assessment of the effect of prandial state on ADC estimates is critical, in order to determine the appropriate patient preparation for biological validation in clinical trials.
authors: 1 Cancer Research UK Cancer Imaging Centre, Division of Radiotherapy and Imaging, Institute of Cancer Research, London, UK.
authors: J M
authors: JM
authors: Winfield
authors: M-V
authors: MV
authors: Papoutsaki
authors: H
authors: H
authors: Ragheb
authors: D M
authors: DM
authors: Morris
authors: A
authors: A
authors: Heerschap
authors: E G W
authors: EG
authors: ter Voert
authors: J P A
authors: JP
authors: Kuijer
authors: I C
authors: IC
authors: Pieters
authors: N H M
authors: NH
authors: Douglas
authors: M
authors: M
authors: Orton
authors: N M
authors: NM
authors: de Souza
mesh_terms: D000328:Adult; D000368:Aged; D038524:Diffusion Magnetic Resonance Imaging; D005215:Fasting; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008099:Liver / Q000033:anatomy & histology*; D008297:Male; D008875:Middle Aged