title: Breast dynamic contrast-enhanced examinations with fat suppression: are contrast-agent uptake curves affected by magnetic field inhomogeneity?
abstract: OBJECTIVE
  To investigate the effect of magnetic field heterogeneity in breast dynamic contrast-enhanced examinations with fat saturation (DCE-FS).
  
  
  METHODS
  The magnetic field was mapped over the breasts in ten patients. DCE-FS was undertaken at 1.5 T with fast spoiled gradient echoes and spectrally selective fat saturation. Signal intensity was calculated for T1 values 25-1,200 ms both on and off resonance, and results were verified with a test object. Clinical examinations were evaluated for the predicted effects of field heterogeneity.
  
  
  RESULTS
  Magnetic field was found to vary by 3.6 ± 1.2 ppm over the central transaxial slice and 5.1 ± 1.5 over the whole breast volume (mean ± standard deviation). Computer simulations predict a reduction in the dynamic range if field heterogeneity leads to unintended water suppression, and distortion to CA uptake curves due to fat suppression failure (for fat containing pixels). A compromise between dynamic range and fat saturation performance is required. Both water suppression and fat suppression failure are apparent in clinical examinations.
  
  
  CONCLUSIONS
  Magnetic field heterogeneity is likely to reduce the sensitivity of DCE-FS by distorting the CA uptake curves because of fat suppression failure (for fat containing pixels) and by reducing the dynamic range because of unintended water suppression.
  
  
  CONCLUSIONS
  • Magnetic field heterogeneity is significant in breast magnetic resonance. • Contrast-agent uptake curves are distorted by a non-uniform magnetic field. • Radiologist must be aware of possibility of distortion to interpret uptake curves correctly. • Compromise between fat suppression and dynamic range is required.
authors.affiliation: Royal Marsden NHS Foundation Trust and Institute of Cancer Research, MRI Unit, Downs Rd, Sutton SM2 5 PT, UK. maria.schmidt@icr.ac.uk
authors.forename: Maria A
authors.initials: MA
authors.lastname: Schmidt
authors.forename: M
authors.initials: M
authors.lastname: Borri
authors.forename: E
authors.initials: E
authors.lastname: Scurr
authors.forename: G
authors.initials: G
authors.lastname: Ertas
authors.forename: G
authors.initials: G
authors.lastname: Payne
authors.forename: E
authors.initials: E
authors.lastname: O'Flynn
authors.forename: N
authors.initials: N
authors.lastname: Desouza
authors.forename: M O
authors.initials: MO
authors.lastname: Leach
mesh_terms: D000273:Adipose Tissue / Q000473:pathology; D000465:Algorithms; D001940:Breast / Q000473:pathology*; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000473:pathology*; D003198:Computer Simulation; D003287:Contrast Media / Q000493:pharmacokinetics*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional; D060526:Magnetic Fields; D015203:Reproducibility of Results; D014867:Water / Q000737:chemistry
chemical_list: D003287:Contrast Media; D014867:Water