title: Evaluation of a short dynamic 18F-fluoride PET/CT scanning method to assess bone metabolic activity in spinal orthopedics.
abstract: OBJECTIVE
  A complication after spinal fusion surgery is pseudarthrosis, but its radiological diagnosis is of limited value. (18)F-fluoride PET with its ability to assess bone metabolism activity could be of value. The goal of this study was to assess the clinical feasibility of calculating the static standardized uptake value (SUV) from a short dynamic scan without the use of blood sampling, thereby obtaining all dynamic and static parameters in a scan of only 30 min. This approach was tested on a retrospective patient population with persisting pain after spinal fusion surgery.
  
  
  METHODS
  In 16 patients, SUVs (SUV max, SUV mean) and kinetic parameters (K 1, k 2, k 3, v b, K i,NLR, K 1/k 2, k 3/(k 2 + k 3), K i,patlak) were derived from static and dynamic PET/CT scans of operated and control regions of the spine, after intravenous administration of 156-214 MBq (18)F-fluoride. Parameter differences between control and operated regions, as well as between pseudarthrosis and fused segments were evaluated. SUVmean at 30 and 60 min was calculated from kinetic parameters obtained from the dynamic data set (SUV mean,2TCM). Agreement between measured and calculated SUVs was evaluated through Bland-Altman plots.
  
  
  RESULTS
  Overall, statistically significant differences between control and operated regions were observed for SUV max, SUV mean, K i,NLR, K i,patlak, K 1/k 2 and k 3/(k 2 + k 3). Diagnostic CT showed pseudarthrosis in 6/16 patients, while in 10/16 patients, segments were fused. Of all parameters, only those regarding the incorporation of bone [K i,NLR, K i,patlak, k 3/(k 2 + k 3)] differed statistically significant in the intervertebral disc space between the pseudarthrosis and fused patients group. The mean values of the patient-specific blood clearance rate [Formula: see text] differed statistically significant between the pseudarthrosis and the fusion group, with a p value of 0.011. This may correspond with the lack of statistical significance of the SUV values between pseudarthrosis and fused patients. Bland-Altman plots show that calculated SUV mean,2TCM values corresponded well with the measured SUV mean values.
  
  
  CONCLUSIONS
  This study shows the feasibility of a 30-min dynamic (18)F-fluoride PET/CT scanning and this may provide dynamic parameters clinically relevant to the diagnosis of pseudarthrosis.
authors.affiliation: Department of Orthopedic Surgery, Maastricht University Medical Center, Postbox 5800, 6202 AZ, Maastricht, The Netherlands. marloes.peters@mumc.nl.
authors.forename: Marloes J M
authors.initials: MJ
authors.lastname: Peters
authors.affiliation: Department of Nuclear Medicine, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Roel
authors.initials: R
authors.lastname: Wierts
authors.affiliation: Department of Orthopedic Surgery, Maastricht University Medical Center, Postbox 5800, 6202 AZ, Maastricht, The Netherlands.
authors.forename: Elisabeth M C
authors.initials: EM
authors.lastname: Jutten
authors.affiliation: Department of Nuclear Medicine, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Servé G E A
authors.initials: SG
authors.lastname: Halders
authors.affiliation: Department of Orthopedic Surgery, Maastricht University Medical Center, Postbox 5800, 6202 AZ, Maastricht, The Netherlands.
authors.forename: Paul C P H
authors.initials: PC
authors.lastname: Willems
authors.affiliation: Department of Nuclear Medicine, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Boudewijn
authors.initials: B
authors.lastname: Brans
mesh_terms: D000328:Adult; D001842:Bone and Bones; D015331:Cohort Studies; D005240:Feasibility Studies; D005260:Female; D005462:Fluorine Radioisotopes; D006801:Humans; D017116:Low Back Pain / Q000000981:diagnostic imaging / Q000378:metabolism / Q000601:surgery; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods; D009985:Orthopedics; D010149:Postoperative Pain / Q000000981:diagnostic imaging / Q000378:metabolism; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D013123:Spinal Fusion / Q000009:adverse effects; D013131:Spine / Q000000981:diagnostic imaging* / Q000378:metabolism* / Q000601:surgery; D013997:Time Factors; D014057:Tomography, X-Ray Computed
chemical_list: D005462:Fluorine Radioisotopes; D019275:Radiopharmaceuticals
keywords: 18F-fluoride PET/CT; Kinetic modeling; Lumbar spine; SUV; Spinal fusion