Comparison of 18F-FDG and 68Ga PET imaging in the assessment of experimental osteomyelitis due to Staphylococcus aureus
- 450 Downloads
Although positron emission tomography (PET) using 2-[18F]fluoro-2-deoxy-D-glucose (18F-FDG) is a promising imaging modality for bone infections, the technique may still give false-positive results due to unspecific uptake in healing bone. This experimental study compared 18F-FDG and 68Ga in PET imaging of osteomyelitis and normal bone healing.
A diffuse osteomyelitis model of the tibia was applied in the rat (n=50). Two weeks after operation, PET imaging with 18F-FDG and 68Ga was performed, followed by peripheral quantitative computed tomography (pQCT) and radiography. Osteomyelitis was verified by quantitative bacteriology. In addition to in vivo imaging, ex vivo measurements of tissue radioactivity were performed to verify uptake of the tracers.
Compared with controls with normal bone healing, the osteomyelitic tibias showed increased SUV ratios (i.e. radioactivity ratios between the operated and non-operated sides) for both 18F-FDG (1.74±0.37) and 68Ga (1.62±0.28) (P<0.001). Ex vivo measurements also showed increased tracer accumulation in the infected bone (P=0.003 for 18F-FDG and P<0.001 for 68Ga). The intensity of 68Ga uptake reflected pathological changes of osteomyelitic bones measured by pQCT. The uptake of 18F-FDG, however, did not show as close a correlation with the anatomical changes. The healing bones without infection exhibited slightly elevated uptake of 18F-FDG (SUV ratio 1.16±0.06), but 68Ga did not accumulate in the healing bone, as judged on the basis of both in vivo imaging (SUV ratio 1.02±0.05) and ex vivo measurements (SUV 0.92±0.21) (P=0.003 and P=0.022 compared with 18F-FDG uptake, respectively).
This study suggests the feasibility of 68Ga PET imaging of bone infections. However, further studies are needed to clarify the value of 68Ga PET for clinical purposes.
KeywordsInfectious disease PET Osteomyelitis 18F-FDG 68Ga
This work was funded by grants from the National Technology Agency of Finland (TEKES), Academy of Finland (grants No. 205757 and No. 103032), the Instrumentarium Foundation and the Finnish Cultural Foundation. T.J.M. and P.L. are PhD students supported by the Finnish Graduate School for Musculoskeletal Diseases. The authors thank Anni Virolainen-Julkunen, MD, PhD, for conducting the PFGE analysis and Tero Vahlberg, MSc, for statistical consultation.
- 3.de Winter F, van de Wiele C, Vogelaers D, de Smet K, Verdonk B, Dierckx RA. Fluorine-18 fluorodeoxyglucose-positron emission tomography: a highly accurate imaging modality for the diagnosis of chronic musculoskeletal infections. J Bone Joint Surg 2001;83A:651–60Google Scholar
- 6.Sugawara Y, Gutowski TD, Fisher SJ, Brown RS, Wahl RL. Uptake of positron emission tomography tracers in experimental bacterial infections: a comparative biodistribution study of radiolabeled FDG, thymidine, L-methionine, 67Ga-citrate, and 125I-HSA. Eur J Nucl Med 1999;26:333–41PubMedCrossRefGoogle Scholar
- 14.Alazraki NP. Gallium-67 imaging in infection. In: Early PJ, Sodee DB, editors. Principles and practice of nuclear medicine, 2nd ed. St. Louis: Mosby-Year Book; 1995. p. 702–13Google Scholar
- 24.Petty W, Spanier S, Shuster JJ, Silverthorne C. The influence of skeletal implants on incidence of infection. Experiments in a canine model. J Bone Joint Surg 1985;67A:1236–44Google Scholar
- 34.Govender S, Csimma C, Genant HK, Valentin-Opran A, Amit Y, Arbel R, et al. Recombinant human bone morphogenetic protein-2 for treatment of open tibial fractures: a prospective, controlled, randomized study of four hundred and fifty patients. J Bone Joint Surg 2002;84A:2123–34Google Scholar