title: 18-Fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography scan for monitoring the therapeutic response in experimental Staphylococcus aureus foreign-body osteomyelitis.
abstract: BACKGROUND
  18-Fluoro-2-deoxy-D-glucose positron emission tomography combined with computed tomography ((18)F-FDG PET/CT) scan is useful for diagnosis of osteoarticular infections. Whether (18)F-FDG PET/CT scanning may be used for therapeutic monitoring is not clear. The objective of this study was to develop (18)F-FDG PET/CT scanning for monitoring therapeutic response to antimicrobials in experimental Staphylococcus aureus osteomyelitis.
  
  
  METHODS
  A total of 22 rabbits were studied. In 20 animals, the right tibia was inoculated intraoperatively with S. aureus. Two control animals were inoculated with normal saline. A needle was placed in the tibia as a foreign body. Infection was allowed to develop for 21 days when (18)F-FDG PET/CT was performed, the needle was removed, and bone specimens were cultured to confirm infection. Antimicrobial therapy with daptomycin was initiated in all successfully infected animals for 1, 3, or 6 weeks. Following completion of treatment, a second (18)F-FDG PET/CT was performed, animals were euthanized, and infected tibias were harvested for quantitative cultures and histology. A positive scan was defined as (18)F-FDG signal activity greater in the infected tibia than that of the contralateral non-infected control tibia. Therapeutic response was measured by the change of (18)F-FDG signal activity in the infected tibia.
  
  
  RESULTS
  All successfully infected animals (n = 14), with microbiologically and/or histologically confirmed osteomyelitis, had positive (18)F-FDG PET/CT scans, while the two control animals had negative scans despite the presence of the foreign body [mean maximum standardized uptake value (SUVmax) (±SD) values 2.96 (±0.80) vs. 1 (±1.10), respectively, P = 0.04]. In the 14 successfully infected animals, the mean SUVmax was significantly higher in the infected compared to the uninfected tibia (P < 0.0001). A SUVmax of 1.4, when used as a cutoff for infection, yielded a diagnostic accuracy of 93 %. At the end of treatment, successfully treated animals and saline controls had a negative (18)F-FDG PET/CT scan (n = 4), while animals with persistent infection despite treatment (n = 12) had a positive (18)F-FDG PET/CT scan (SUVmax 1.0-3.0) (p < 0.001). SUVmax values were significantly reduced after 42 days of treatment from 3.15 ± 0.5 (day 7) to 1.71 ± 0.37 (day 42) (p = 0.05).
  
  
  CONCLUSIONS
  (18)F-FDG PET/CT scan is a sensitive and specific tool in therapeutic monitoring of experimental foreign-body osteomyelitis.
authors: Second Department of Radiology, Medical School, National and Kapodistrian University of Athens, Athens, Greece. sofiac@bcm.edu.|PET/CT Section, Foundation for Biomedical Research of the Academy of Athens, Athens, Greece. sofiac@bcm.edu.
authors: Sofia
authors: S
authors: Chatziioannou
authors: Third Department of Orthopedics, Medical School, National and Kapodistrian University of Athens, Athens, Greece. papamichosod@yahoo.gr.
authors: Odysseas
authors: O
authors: Papamichos
authors: Department of Pathophysiology, Medical School, National and Kapodistrian University of Athens, Mikras Asias 75, Athens, 115 27, Greece. magama@med.uoa.gr.
authors: Maria N
authors: MN
authors: Gamaletsou
authors: PET/CT Section, Foundation for Biomedical Research of the Academy of Athens, Athens, Greece. ageorgakop@bioacademy.gr.
authors: Alexandros
authors: A
authors: Georgakopoulos
authors: Center for Experimental Surgery, Foundation for Biomedical Research of the Academy of Athens, Athens, Greece. nkostom@bioacademy.gr.
authors: Nikolaos G
authors: NG
authors: Kostomitsopoulos
authors: Department of Pathology, Medical School, National and Kapodistrian University of Athens, Athens, Greece. stseleni@med.uoa.gr.
authors: Sofia
authors: S
authors: Tseleni-Balafouta
authors: Department of Microbiology, Medical School, National and Kapodistrian University of Athens, Athens, Greece. ipapapar@med.uoa.gr.
authors: Joseph
authors: J
authors: Papaparaskevas
authors: Departments of Medicine, Pediatrics, and Microbiology & Immunology, Weill Cornell Medical Center of Cornell University, New York, NY, USA. thw2003@med.cornell.edu.
authors: Thomas J
authors: TJ
authors: Walsh
authors: Third Department of Orthopedics, Medical School, National and Kapodistrian University of Athens, Athens, Greece. irosp@bcm.tmc.edu.
authors: Spiros G
authors: SG
authors: Pneumaticos
authors: Department of Pathophysiology, Medical School, National and Kapodistrian University of Athens, Mikras Asias 75, Athens, 115 27, Greece. nsipsas@med.uoa.gr.
authors: Nikolaos V
authors: NV
authors: Sipsas
mesh_terms: D000818:Animals; D019788:Fluorodeoxyglucose F18; D005547:Foreign Bodies / Q000000981:diagnostic imaging*; D008297:Male; D010019:Osteomyelitis / Q000000981:diagnostic imaging*; D049268:Positron-Emission Tomography / Q000379:methods; D011817:Rabbits; D013203:Staphylococcal Infections / Q000000981:diagnostic imaging*; D013211:Staphylococcus aureus / Q000302:isolation & purification; D014057:Tomography, X-Ray Computed / Q000379:methods; D016896:Treatment Outcome
chemical_list: D019788:Fluorodeoxyglucose F18