title: Differences in regional bone metabolism at the spine and hip: a quantitative study using (18)F-fluoride positron emission tomography.
abstract: CONCLUSIONS
  This study showed that regional bone blood flow and (18)F-fluoride bone plasma clearance measured by positron emission tomography are three times lower at the hip than the lumbar spine.
  
  
  BACKGROUND
  Measurements of effective bone plasma flow (K (1)), bone plasma clearance (K ( i )) and standardised uptake values (SUV) using (18)F-fluoride positron emission tomography ((18)F-PET) provide a useful means of studying regional bone metabolism at different sites in the skeleton. This study compares the regional (18)F-fluoride kinetics and SUV at the hip and lumbar spine (LS).
  
  
  METHODS
  Twelve healthy postmenopausal women with no history of metabolic bone disease apart from two with untreated osteoporosis were recruited. Each subject underwent 60-min dynamic (18)F-PET scans at the LS and proximal femur two weeks apart. K (1), K ( i ) and SUV were measured at the LS (mean of L(1)-L(4)), femoral neck (FN), total hip (TH) and femoral shaft (FS). Differences between sites were assessed using the nonparametric Kruskal-Wallis test with a Bonferroni correction for multiple comparisons.
  
  
  RESULTS
  Values of K (1), K ( i ) and SUV at the FN, TH and FS were three times lower than at the LS (p = 0.003). Amongst the proximal femur sites, K ( i ) and SUV were lower at the FS compared with the FN and TH, and SUV was lower at the TH compared with the FN (all p < 0.05). The volume of distribution was lower at the TH and FS compared with the LS (p < 0.05).
  
  
  CONCLUSIONS
  The lower values of K (1), K ( i ) and SUV at the hip suggest that lower bone blood flow in the proximal femur is an important factor explaining the principal reason for the differences in bone fluoride kinetics between the LS and hip sites.
authors.affiliation: King's College London, PET Imaging Centre, Imaging Sciences and Biomedical Engineering, St. Thomas' Hospital, London, UK. tanujpuri82@gmail.com
authors.forename: T
authors.initials: T
authors.lastname: Puri
authors.forename: M L
authors.initials: ML
authors.lastname: Frost
authors.forename: K M
authors.initials: KM
authors.lastname: Curran
authors.forename: M
authors.initials: M
authors.lastname: Siddique
authors.forename: A E B
authors.initials: AE
authors.lastname: Moore
authors.forename: G J R
authors.initials: GJ
authors.lastname: Cook
authors.forename: P K
authors.initials: PK
authors.lastname: Marsden
authors.forename: I
authors.initials: I
authors.lastname: Fogelman
authors.forename: G M
authors.initials: GM
authors.lastname: Blake
mesh_terms: D015502:Absorptiometry, Photon; D015519:Bone Density / Q000502:physiology; D005260:Female; D005272:Femur Neck / Q000098:blood supply / Q000000981:diagnostic imaging / Q000378:metabolism / Q000502:physiology; D019788:Fluorodeoxyglucose F18; D006621:Hip Joint / Q000098:blood supply / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000502:physiology; D006801:Humans; D008159:Lumbar Vertebrae / Q000098:blood supply / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000502:physiology; D008875:Middle Aged; D010865:Pilot Projects; D049268:Positron-Emission Tomography / Q000379:methods; D017698:Postmenopause / Q000502:physiology; D019275:Radiopharmaceuticals; D012039:Regional Blood Flow
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18