title: Vertebral bone mineral density, marrow perfusion, and fat content in healthy men and men with osteoporosis: dynamic contrast-enhanced MR imaging and MR spectroscopy.
abstract: OBJECTIVE
  To prospectively use hydrogen 1 (1H) magnetic resonance (MR) spectroscopy and dynamic contrast material-enhanced MR imaging to measure vertebral body marrow fat content and bone marrow perfusion in older men with varying bone mineral densities as documented with dual x-ray absorptiometry (DXA).
  
  
  METHODS
  This study had institutional review board approval, and all participants provided informed consent. DXA, 1H MR spectroscopy, and dynamic contrast-enhanced MR imaging of the lumbar spine were performed in 90 men (mean age, 73 years; range, 67-101 years). Vertebral marrow fat content and perfusion (maximum enhancement and enhancement slope) were compared for subject groups with differing bone densities (normal, osteopenic, and osteoporotic). The t test was used for comparisons between groups, and the Pearson test was used to determine correlation between marrow fat content and perfusion indexes.
  
  
  RESULTS
  Eight subjects were excluded, yielding a final cohort of 82 subjects (mean age, 73 years; range, 67-101 years) that included 42 subjects with normal bone density (mean T score, 0.8 +/- 1.1 [standard deviation]), 23 subjects with osteopenia (mean T score, -1.6 +/- 0.4), and 17 subjects with osteoporosis (mean T score, -3.2 +/- 0.5). Vertebral marrow fat content was significantly increased in subjects with osteoporosis (mean fat content, 58.23% +/- 7.8) (P = .002) or osteopenia (mean fat content, 55.68% +/- 10.2) (P = .034) compared with that in subjects with normal bone density (50.45% +/- 8.7). Vertebral marrow perfusion indexes were significantly decreased in osteoporotic subjects (mean enhancement slope, 0.78%/sec +/- 0.3) compared with those in osteopenic subjects (mean enhancement slope, 1.15%/sec +/- 0.6) (P = .007) and those in subjects with normal bone density (mean enhancement slope, 1.48%/sec +/- 0.7) (P < .001).
  
  
  CONCLUSIONS
  Subjects with osteoporosis have decreased vertebral marrow perfusion and increased marrow fat compared with these parameters in subjects with osteopenia. Similarly, subjects with osteopenia have decreased vertebral marrow perfusion and increased marrow fat compared with these parameters in subjects with normal bone density.
authors.affiliation: Department of Diagnostic Radiology, Chinese University of Hong Kong, Prince of Wales Hospital, 30-32 Ngan Shing St, Shatin, Hong Kong SAR, China.
authors.forename: James F
authors.initials: JF
authors.lastname: Griffith
authors.forename: David K W
authors.initials: DK
authors.lastname: Yeung
authors.forename: Gregory E
authors.initials: GE
authors.lastname: Antonio
authors.forename: Francis K H
authors.initials: FK
authors.lastname: Lee
authors.forename: Athena W L
authors.initials: AW
authors.lastname: Hong
authors.forename: Samuel Y S
authors.initials: SY
authors.lastname: Wong
authors.forename: Edith M C
authors.initials: EM
authors.lastname: Lau
authors.forename: Ping Chung
authors.initials: PC
authors.lastname: Leung
mesh_terms: D015502:Absorptiometry, Photon; D000273:Adipose Tissue / Q000473:pathology*; D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density; D001853:Bone Marrow / Q000098:blood supply* / Q000473:pathology*; D003287:Contrast Media; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D010024:Osteoporosis / Q000473:pathology*; D011446:Prospective Studies; D013131:Spine / Q000473:pathology*
chemical_list: D003287:Contrast Media