title: Demonstration of the reproducibility of free-breathing diffusion-weighted MRI and dynamic contrast enhanced MRI in children with solid tumours: a pilot study.
abstract: OBJECTIVE
  The objectives are to examine the reproducibility of functional MR imaging in children with solid tumours using quantitative parameters derived from diffusion-weighted (DW-) and dynamic contrast enhanced (DCE-) MRI.
  
  
  METHODS
  Patients under 16-years-of age with confirmed diagnosis of solid tumours (n = 17) underwent free-breathing DW-MRI and DCE-MRI on a 1.5 T system, repeated 24 hours later. DW-MRI (6 b-values, 0-1000 sec/mm(2)) enabled monoexponential apparent diffusion coefficient estimation using all (ADC0-1000) and only ≥100 sec/mm(2) (ADC100-1000) b-values. DCE-MRI was used to derive the transfer constant (K(trans)), the efflux constant (kep), the extracellular extravascular volume (ve), and the plasma fraction (vp), using a study cohort arterial input function (AIF) and the extended Tofts model. Initial area under the gadolinium enhancement curve and pre-contrast T1 were also calculated. Percentage coefficients of variation (CV) of all parameters were calculated.
  
  
  RESULTS
  The most reproducible cohort parameters were ADC100-1000 (CV = 3.26%), pre-contrast T1 (CV = 6.21%), and K(trans) (CV = 15.23%). The ADC100-1000 was more reproducible than ADC0-1000, especially extracranially (CV = 2.40% vs. 2.78%). The AIF (n = 9) derived from this paediatric population exhibited sharper and earlier first-pass and recirculation peaks compared with the literature's adult population average.
  
  
  CONCLUSIONS
  Free-breathing functional imaging protocols including DW-MRI and DCE-MRI are well-tolerated in children aged 6 - 15 with good to moderate measurement reproducibility.
  
  
  CONCLUSIONS
  • Diffusion MRI protocol is feasible and well-tolerated in a paediatric oncology population. • DCE-MRI for pharmacokinetic evaluation is feasible and well tolerated in a paediatric oncology population. • Paediatric arterial input function (AIF) shows systematic differences from the adult population-average AIF. • Variation of quantitative parameters from paired functional MRI measurements were within 20%.
authors.affiliation: Cancer Research UK Cancer Imaging Centre at The Institute of Cancer Research, London, SM2 5NG, UK.
authors.forename: Keiko
authors.initials: K
authors.lastname: Miyazaki
authors.forename: Neil P
authors.initials: NP
authors.lastname: Jerome
authors.forename: David J
authors.initials: DJ
authors.lastname: Collins
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Orton
authors.forename: James A
authors.initials: JA
authors.lastname: d'Arcy
authors.forename: Toni
authors.initials: T
authors.lastname: Wallace
authors.forename: Lucas
authors.initials: L
authors.lastname: Moreno
authors.forename: Andrew D J
authors.initials: AD
authors.lastname: Pearson
authors.forename: Lynley V
authors.initials: LV
authors.lastname: Marshall
authors.forename: Fernando
authors.initials: F
authors.lastname: Carceller
authors.forename: Martin O
authors.initials: MO
authors.lastname: Leach
authors.forename: Stergios
authors.initials: S
authors.lastname: Zacharoulis
authors.forename: Dow-Mu
authors.initials: DM
authors.lastname: Koh
mesh_terms: D000293:Adolescent; D002648:Child; D015331:Cohort Studies; D003287:Contrast Media; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D005682:Gadolinium; D006801:Humans; D007089:Image Enhancement; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008297:Male; D009369:Neoplasms / Q000175:diagnosis*; D010865:Pilot Projects; D015203:Reproducibility of Results; D012119:Respiration; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D005682:Gadolinium