Osteomyelitis is a serious disease which can be difficult to treat despite properly instituted antibiotic therapy. This appears to be related at least partly to degraded vascularisation in the osteomyelitic (OM) lesions. Studies of perfusion in OM bones are, however, few and not quantitative. Quantitative assessment of perfusion could aid in the selection of therapy. A non-invasive, quantitative way to study perfusion is dynamic [15O]water positron emission tomography (PET). We aim to demonstrate that the method can be used for measuring perfusion in OM lesions and hypothesize that perfusion will be less elevated in OM lesions than in soft tissue (ST) infection. The study comprised 11 juvenile pigs with haematogenous osteomyelitis induced by injection of Staphylococcus aureus into the right femoral artery 1 week before scanning (in one pig, 2 weeks). The pigs were dynamically PET scanned with [15O]water to quantify blood perfusion. OM lesions (N = 17) in long bones were studied, using the left limb as reference. ST lesions (N = 8) were studied similarly. Perfusion was quantitatively determined. Perfusion was elevated by a factor 1.5 in OM lesions and by a factor 6 in ST lesions. Blood perfusion was successfully determined in pathological subacute OM lesions; average perfusion was increased compared to that in a healthy bone, but as hypothesized, the increase was less than in ST lesions, indicating that the infected bone has less perfusion reserve than the infected soft tissue.

Introduction: Radiotracers are widely used in medical imaging, using techniques of gamma-camera imaging (scintigraphy and SPECT) or positron emission tomography (PET). In bone marrow infection, there is no single routine test available that can detect infection with sufficiently high diagnostic accuracy. Here, we review radiotracers used for imaging of bone marrow infection, also known as osteomyelitis, with a focus on why these molecules are relevant for the task, based on their physiological uptake mechanisms. The review comprises [⁶⁷Ga]Ga-citrate, radiolabelled leukocytes, radiolabelled nanocolloids (bone marrow) and radiolabelled phosphonates (bone structure), and [¹⁸F]FDG as established radiotracers for bone marrow infection imaging. Tracers that are under development or testing for this purpose include [⁶⁸Ga]Ga-citrate, [¹⁸F]FDG, [¹⁸F]FDS and other non-glucose sugar analogues, [¹⁵O]water, [¹¹C]methionine, [¹¹C]donepezil, [^99mTc]Tc-IL-8, [⁶⁸Ga]Ga-Siglec-9, phage-display selected peptides, and the antimicrobial peptide [^99mTc]Tc-UBI_29-41 or [⁶⁸Ga]Ga-NOTA-UBI_29-41. Conclusion: Molecular radiotracers allow studies of physiological processes such as infection. None of the reviewed molecules are ideal for the imaging of infections, whether bone marrow or otherwise, but each can give information about a separate aspect such as physiology or biochemistry. Knowledge of uptake mechanisms, pitfalls, and challenges is useful in both the use and development of medically relevant radioactive tracers.

Objective. Sjögren's syndrome (SS) is considered to be a universal exocrinopathy most likely based on autoimmune mechanisms. The degree of exocrine involvement in SS with the exception of salivary and lachrymal glands is, however, not yet established. Material and methods. We therefore examined the morphology, the exocrine and endocrine functions of the pancreas in 12 healthy consecutively included levolunteers with established SS, but without known pancreatic disease, using secretin-stimulated magnetic resonance cholangiopancreatography (MRCP), a Lundh test, oral glucose tolerance test, and blood sampling. Results. Twenty-five percent of the patients had morphological changes of pancreas as evaluated by secretin-stimulated MRCP, and two patients had chronic pancreatitis-like changes. Four patients had reduced exocrine function of the pancreas with either significantly reduced amylase and/or lipase in the pancreatic juice. Conclusions. The prevalence of pancreatic dysfunction was increased to 25–33% in the study population which is much higher than in the background population. Thus, pancreatic dysfunction and chronic pancreatitis should be considered in SS.

To assess distal blood pressures (BPs) in ankle and toe, walking capacity, intermittent claudication symptoms, physical activity and self-rated health after intermittent vacuum treatment (IVT) for peripheral artery disease (PAD). Forty-eight patients with PAD were randomised to either a control (C)-group with lifestyle changes or lifestyle changes in combination with VacuMed((R)) treatment thrice weekly for 6 weeks. Ankle and toe BPs were measured before, after 6 weeks of intervention and after 6 weeks follow-up. Walking capacity, intermittent claudication symptoms, physical activity and self-rated health (Likert scale) were also assessed. The ankle to brachial index (ABI) and BPs in the ankle and toe decreased after 6 and 12 weeks in both groups with no difference between the groups. In the legs with the lowest ABI at baseline in each patient, there were no differences regarding ABI, BPs and toe-systolic BP index between the groups after either the intervention or the follow-up period. The BPs decreased in both groups. The walking distance and the time to pain were unchanged in the IVT-group and increased in the C-group after the follow-up period, but without any significant differences between the groups. The level of objectively tested physical activity and self-rated health remained unchanged throughout the study in both the IVT- and the C-group. There were no differences between the changes of the self-rated health data during the study period between the IVT- and the C-group. VacuMed((R)) had no effect per se on distal blood pressures, walking capacity, intermittent claudication symptoms, physical activity and self-rated health.