title: Quantification of skeletal blood flow and fluoride metabolism in rats using PET in a pre-clinical stress fracture model.
abstract: OBJECTIVE
  Blood flow is an important factor in bone production and repair, but its role in osteogenesis induced by mechanical loading is unknown. Here, we present techniques for evaluating blood flow and fluoride metabolism in a pre-clinical stress fracture model of osteogenesis in rats.
  
  
  METHODS
  Bone formation was induced by forelimb compression in adult rats. (15)O water and (18)F fluoride PET imaging were used to evaluate blood flow and fluoride kinetics 7 days after loading. (15)O water was modeled using a one-compartment, two-parameter model, while a two-compartment, three-parameter model was used to model (18)F fluoride. Input functions were created from the heart, and a stochastic search algorithm was implemented to provide initial parameter values in conjunction with a Levenberg-Marquardt optimization algorithm.
  
  
  RESULTS
  Loaded limbs are shown to have a 26% increase in blood flow rate, 113% increase in fluoride flow rate, 133% increase in fluoride flux, and 13% increase in fluoride incorporation into bone as compared to non-loaded limbs (p < 0.05 for all results).
  
  
  CONCLUSIONS
  The results shown here are consistent with previous studies, confirming this technique is suitable for evaluating the vascular response and mineral kinetics of osteogenic mechanical loading.
authors.affiliation: Department of Orthopaedic Surgery, Washington University in St. Louis, St. Louis, MO 63110, USA.
authors.forename: Ryan E
authors.initials: RE
authors.lastname: Tomlinson
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Silva
authors.forename: Kooresh I
authors.initials: KI
authors.lastname: Shoghi
mesh_terms: D000465:Algorithms; D000818:Animals; D001133:Bones of Upper Extremity / Q000098:blood supply* / Q000000981:diagnostic imaging / Q000293:injuries / Q000378:metabolism*; D005462:Fluorine Radioisotopes / Q000493:pharmacokinetics*; D015775:Fractures, Stress / Q000000981:diagnostic imaging* / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D010012:Osteogenesis / Q000502:physiology; D010104:Oxygen Radioisotopes / Q000493:pharmacokinetics; D049268:Positron-Emission Tomography / Q000379:methods*; D051381:Rats; D011916:Rats, Inbred F344; D013314:Stress, Mechanical; D014018:Tissue Distribution
chemical_list: D005462:Fluorine Radioisotopes; D010104:Oxygen Radioisotopes