title: Bone marrow diffusion in osteoporosis: evaluation with quantitative MR diffusion imaging.
abstract: OBJECTIVE
  To determine the diffusion of vertebral body marrow with quantitative MR diffusion imaging and to examine whether differences exist between subjects with postmenopausal osteoporosis and premenopausal control subjects.
  
  
  METHODS
  A total of 44 consecutive women (mean age, 70 years) with documented bone mineral density (BMD) measured by dual energy x-ray absorptiometry (T-score) and 20 normal subjects (mean age, 28 years) were examined with echo-planar diffusion imaging at 1.5 T using b values of 0, 20, 40, 60, 80, 100, 200, 300, 400, and 500 seconds/mm2. Extravascular diffusion (D) and apparent diffusion coefficient (ADC) were calculated and results from both groups compared.
  
  
  RESULTS
  Both D and ADC values tended to decrease with decreasing BMD. Mean D values were significantly lower in postmenopausal women with reduced BMD (0.42 +/- 0.12 x 10(-3) mm2/second) than normal premenopausal women (0.50 +/- 0.09 x 10(-3) mm2/second). Mean ADC values were significantly lower both in subjects with reduced BMD (0.41 +/- 0.10 x 10(-3) mm2/second) and normal BMD (0.43 +/- 0.08 x 10(-3) mm2/second) compared to normal controls (0.49 +/- 0.07 x 10(-3) mm2/second).
  
  
  CONCLUSIONS
  Accumulation of fatty bone marrow associated with osteoporosis is reflected by a decrease in D and ADC. Diffusion imaging may prove useful in the study of osteoporosis.
authors.affiliation: Department of Clinical Oncology, Prince of Wales Hospital, Hong Kong, China. dkyeung@cuhk.edu.hk
authors.forename: David K W
authors.initials: DK
authors.lastname: Yeung
authors.forename: Samuel Y S
authors.initials: SY
authors.lastname: Wong
authors.forename: James F
authors.initials: JF
authors.lastname: Griffith
authors.forename: Edith M C
authors.initials: EM
authors.lastname: Lau
mesh_terms: D000328:Adult; D000368:Aged; D015519:Bone Density / Q000502:physiology; D001853:Bone Marrow / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D008875:Middle Aged; D010024:Osteoporosis / Q000175:diagnosis*; D019047:Phantoms, Imaging; D017698:Postmenopause; D017697:Premenopause; D012016:Reference Values; D013997:Time Factors