An untapped potential for imaging of peripheral osteomyelitis in paediatrics using [18F]FDG PET/CT —the inference from a juvenile porcine model

Abstract

PurposeTo examine parameters affecting the detection of osteomyelitis (OM) by [18F]FDG PET/CT and to reduce tracer activity in a pig model.Background[18F]FDG PET/CT is recommended for the diagnosis of OM in the axial skeleton of adults. In children, OM has a tendency to become chronic or recurrent, especially in low-income countries. Early diagnosis and initiation of therapy are therefore essential. We have previously demonstrated that [18F]FDG PET/CT is promising in juvenile Staphylococcus aureus (S. aureus) OM of peripheral bones in a pig model, not failing even small lesions. When using imaging in children, radiation exposure should be balanced against fast diagnostics in the individual case.MethodsTwenty juvenile pigs were inoculated with S. aureus. One week after inoculation, the pigs were [18F]FDG PET/CT scanned. PET list-mode acquired data of a subgroup were retrospectively processed in order to simulate and examine the image quality obtainable with an injected activity of 132 MBq, 44 MBq, 13.2 MBq, and 4.4 MBq, respectively.ResultsAll lesions were detected by [18F]FDG PET and CT. Some lesions were very small (0.01 cm3), and others were larger (4.18 cm3). SUVmax was higher when sequesters (p = 0.023) and fistulas were formed (p < 0.0001). The simulated data demonstrated that it was possible to reduce the activity to 4.4 MBq without compromising image quality in pigs.Conclusions[18F]FDG PET/CT localized even small OM lesions in peripheral bones. It was possible to reduce the injected activity considerably without compromising image quality, impacting the applicability of PET/CT in peripheral OM in children.

Kinetic Modelling of [68Ga]Ga-DOTA-Siglec-9 in Porcine Osteomyelitis and Soft Tissue Infections

“…All pigs in the table except no. 24 were also included in [21] (with different numbering). Blood sample data on [ 68 Ga]Ga-DOTA-Siglec-9 in pig no.…”

Lymph Nodes Draining Infections Investigated by PET and Immunohistochemistry in a Juvenile Porcine Model

“…Thus, the increase in area fractions of IL-8 positive cells of mammary lymph nodes is probably an effect of the activation and migration of neutrophils. We have also previously reported that IL-8 plays a role in OM, as [99mTc]Tc-IL-8 detects 70% of OM lesions compared to a 100% sensitivity of [ 18 F]FDG PET/CT [17].…”

“…The glucose analog 2-[ 18 F]fluoro-2-deoxyglucose ([ 18 F]FDG) is used extensively in PET for cancer diagnostics and staging, but also, to some extent, in inflammatory and infectious diseases [1]. Thus, [ 18 F]FDG PET cannot distinguish malignancy from inflammation or infection [2]. Another issue is the physiological accumulation of [ 18 F]FDG in normal tissues such as growth zones of juvenile bones, the heart muscle, and the brain.…”

“…We, therefore, have tested multiple radiotracers, and improved a juvenile pig model for osteomyelitis, using S. aureus as the infectant due to this pathogen's commonness in osteomyelitis [5]. Though [ 18 F]FDG was the most sensitive tracer to detect osteomyelitis and soft tissue abscesses, [ 11 C]methionine appeared to be more sensitive than [ 18 F]FDG for identifying the lymph nodes draining the infected limb [6][7][8][9]. [ 11 C]methionine accumulated in all enlarged lymph nodes, whereas [ 18 F]FDG accumulated in 50% [8].…”

Attempts to Target Staphylococcus aureus Induced Osteomyelitis Bone Lesions in a Juvenile Pig Model by Using Radiotracers

“…[ 18 F]FDG secures that no OM is unnoticed. We have previously addressed a possible reduction of [ 18 F]FDG activity in children [ 26 ].…”