title: Temperature dependence of the magnetic volume susceptibility of human breast fat tissue: an NMR study.
abstract: OBJECTIVE
  Proton resonance frequency shift (PRFS)-based MR thermometry (MRT) is hampered by heat-induced susceptibility changes when applied in tissues containing fat, e.g., the human breast. In order to assess the impact of fat susceptibility changes on PRFS-based MRT during thermal therapy in the human breast, reliable knowledge of the temperature dependence of the magnetic volume susceptibility of fat, dχ(fat)/dT, is a prerequisite. In this work we have measured dχ(fat)/dT of human breast fat tissue, using a double-reference method to ensure invariance to temperature-induced changes in the proton electron screening constant.
  
  
  METHODS
  Ex vivo measurements were taken on a 14.1 T five mm narrow bore NMR spectrometer. Breast fat tissue samples were collected from six subjects, directly postmortem. The susceptibility was measured over a temperature range from 24°C to 65°C.
  
  
  RESULTS
  A linear behavior of the susceptibility over temperature was observed for all samples. The resulting dχ(fat)/dT of human breast fat ranged between 0.0039 and 0.0076 ppm/°C.
  
  
  CONCLUSIONS
  It is concluded that the impact of heat-induced susceptibility changes of fat during thermal therapy in the breast may not be neglected.
authors.affiliation: Image Sciences Institute/Department of Radiology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands. sara.sprinkhuizen@gmail.com
authors.forename: Sara M
authors.initials: SM
authors.lastname: Sprinkhuizen
authors.forename: Chris J G
authors.initials: CJ
authors.lastname: Bakker
authors.forename: Johannes H
authors.initials: JH
authors.lastname: Ippel
authors.forename: Rolf
authors.initials: R
authors.lastname: Boelens
authors.forename: Max A
authors.initials: MA
authors.lastname: Viergever
authors.forename: Lambertus W
authors.initials: LW
authors.lastname: Bartels
mesh_terms: D000273:Adipose Tissue / Q000473:pathology; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001940:Breast / Q000473:pathology*; D004583:Electrons; D004867:Equipment Design; D006358:Hot Temperature; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008280:Magnetics; D008875:Middle Aged; D011522:Protons; D015203:Reproducibility of Results; D013053:Spectrophotometry / Q000379:methods; D013696:Temperature
chemical_list: D011522:Protons