title: Influence of bone marrow composition on measurements of trabecular microstructure using decay due to diffusion in the internal field MRI: simulations and clinical studies.
abstract: OBJECTIVE
  Decay due to diffusion in the internal field (DDIF) MRI allows for measurements of microstructures of porous materials at low spatial resolution and thus has potential for trabecular bone quality measurements. In trabecular bone, solid bone changes (osteoporosis) as well as changes in bone marrow composition occur. The influence of such changes on DDIF MRI was studied by simulations and in vivo measurements.
  
  
  METHODS
  Monte Carlo simulations of DDIF in various trabecular bone models were conducted. Changes in solid bone and marrow composition were simulated with numerical bone erosion and marrow susceptibility variations. Additionally, in vivo measurements were performed in the lumbar spine of healthy volunteers aged 23-62 years.
  
  
  RESULTS
  Simulations and in vivo results showed that 1) DDIF decay times decrease with increasing marrow fat and 2) the marrow fat percentage needs to be incorporated in the DDIF analysis to discriminate between healthy and osteoporotic solid bone structures.
  
  
  CONCLUSIONS
  Bone marrow composition plays an important role in DDIF MRI: incorporation of marrow fat percentage into DDIF MRI allowed for differentiation of young and old age groups (in vivo experiments). DDIF MRI may develop into a means of assessing osteoporosis and disorders that affect marrow composition.
authors.affiliation: Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts, USA.
authors.forename: Sara M
authors.initials: SM
authors.lastname: Sprinkhuizen
authors.forename: Jerome L
authors.initials: JL
authors.lastname: Ackerman
authors.forename: Yi-Qiao
authors.initials: YQ
authors.lastname: Song
mesh_terms: D000328:Adult; D016477:Artifacts; D001854:Bone Marrow Cells / Q000166:cytology*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008159:Lumbar Vertebrae / Q000166:cytology*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
keywords: Monte Carlo; diffusion; marrow; osteoporosis; stimulated echo; trabecular bone