title: Predictive value of [18F]-fluoride PET for monitoring bone remodeling in patients with orthopedic conditions treated with a Taylor spatial frame.
abstract: OBJECTIVE
  The Taylor Spatial Frame (TSF) is used to correct orthopedic conditions such as correction osteotomies in delayed fracture healing and pseudarthrosis. Long-term TSF-treatments are common and may lead to complications. Current conventional radiological methods are often unsatisfactory for therapy monitoring. Hence, an imaging technique capable of quantifying bone healing progression would be advantageous.
  
  
  METHODS
  A cohort of 24 patients with different orthopedic conditions, pseudarthrosis (n = 10), deformities subjected to correction osteotomy (n = 9), and fracture (n = 5) underwent dynamic [18F]-fluoride (Na18F) PET/CT at 8 weeks and 4 months, respectively, after application of a TSF. Parametric images, corresponding to the net transport rate of [18F]-fluoride from plasma to bone, Kiwere calculated. The ratio of the maximum Kiat PET scan 2 and 1 ([Formula: see text]) as well as the ratio of the maximum Standard Uptake Value at PET scan 2 and 1 ([Formula: see text]) were calculated for each individual. Different treatment end-points were scored, and the overall treatment outcome score was compared with the osteoblastic activity progression as scored with [Formula: see text] or [Formula: see text].
  
  
  RESULTS
  [Formula: see text] and [Formula: see text] were not correlated within each orthopedic group (p > 0.1 for all groups), nor for the pooled population (p = 0.12). The distribution of [Formula: see text] was found significantly different among the different orthopedic groups (p = 0.0046) -also for [Formula: see text] (p = 0.022). The positive and negative treatment predictive values for [Formula: see text] were 66.7 % and 77.8 %, respectively. Corresponding values for [Formula: see text] were 25 % and 33.3 % CONCLUSIONS: The [Formula: see text] obtained from dynamic [18F]-fluoride-PET imaging is a promising predictive factor to evaluate changes in bone healing in response to TSF treatment.
authors.affiliation: Department of Hospital Physics, Nuclear medicine, Karolinska University Hospital, Stockholm, Sweden. alejandro.sanchez-crespo@karolinska.se.|Karolinska University Hospital, Nuklearmedicin A3:01, S-171 76, Stockholm, Sweden. alejandro.sanchez-crespo@karolinska.se.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Sanchez-Crespo
authors.affiliation: Department of Radiology, Nyköpings Hospital, Nyköping, Sweden.
authors.forename: Frederik
authors.initials: F
authors.lastname: Christiansson
authors.affiliation: Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Charlotte Karlsson
authors.initials: CK
authors.lastname: Thur
authors.affiliation: Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Henrik
authors.initials: H
authors.lastname: Lundblad
authors.affiliation: Department of Radiology and Molecular Imaging, Uppsala University Hospital, Uppsala, Sweden.
authors.forename: Anders
authors.initials: A
authors.lastname: Sundin
mesh_terms: D000328:Adult; D000368:Aged; D016723:Bone Remodeling; D016267:External Fixators / Q000009:adverse effects; D005260:Female; D019788:Fluorodeoxyglucose F18; D050723:Fractures, Bone / Q000000981:diagnostic imaging* / Q000628:therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D019637:Orthopedic Procedures / Q000009:adverse effects* / Q000295:instrumentation / Q000379:methods; D000072078:Positron Emission Tomography Computed Tomography; D011237:Predictive Value of Tests; D011542:Pseudarthrosis / Q000000981:diagnostic imaging* / Q000628:therapy; D019275:Radiopharmaceuticals
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: Fluoride; Influx rate; PET/CT; Parametric PET imaging; SUV; TSF