Background.Patients presenting with pyrexia of unknown origin, symptoms of sepsis or bacteraemia without a confirmed or suspected source can present a significant diagnostic dilemma. 67 Ga-citrate scanning has had a role in the investigation of patients of sepsis of unknown origin since the 1970s, however the introduction of SPECT/CT over the last two decades has offered improved specificity of diagnosis.Aims.To evaluate the diagnostic yield of modern 67 Ga-citrate scanning in the investigation of patients without a confirmed site of infection, including those with or without a suspected site of infection.Methods.A retrospective audit was undertaken of 100 consecutive records of patients undergoing 67 Ga-citrate scanning at Royal North Shore Hospital, Sydney.Recorded information included general patient demographics, provided clinical information/history, and primary and secondary diagnoses.A subgroup analysis was performed on patients without a confirmed site of infection prior to their study.Results.61/100 patients in the cohort did not have a confirmed site of infection prior to their 67 Ga-citrate scan as per their clinical history.32/61 had a suspected site of infection based on localising symptoms and examination findings.34/61 patients had a positive scan result identifying an infective or inflammatory process.20/29 patients with no clinically suspicious site of infection had a documented positive blood culture.Of this blood culture positive group, 9/20 had a site of infection identified (5 skeletal).Among the 9 patients with a negative blood culture, 2 scans localised the infection (both pyelonephritis).23/32 patients with a suspected site of infection had the culprit lesion identified on 67 Ga-citrate scanincluding 16 likely infections and 7 inflammatory processes (including tenosynovitis, plantar fasciitis and seronegative arthritis).11/61 patients were investigated for possible spinal infection, with a diagnosis of active spinal infection made in 7/11. Conclusion.67 Ga-citrate scanning has demonstrated value in evaluating patients with suspected but unconfirmed patients.In this cohort, almost two thirds of patients with localising symptoms had a culprit infective or inflammatory lesion confirmed, and a site of occult infection was found in almost half of patients with bacteraemia.

AIM: To evaluate the diagnostic performance of whole-body (WB) integrated single photon emission tomography (SPECT)/computed tomography (CT) in detecting bone metastasis (BM) and to investigate whether WB-SPECT/CT offered any additional benefit value compared to planar bone scintigraphy (PBS) with 99mTc-hydroxy-methylene diphosphonate or 99mTc methylene diphosphonate. MATERIALS AND METHODS: Medline, EMBASE, SCOPUS, Web of Science, and CINAHL were searched systematically up to 28 August 2019. All studies using histopathological analysis and/ or follow-up imaging and clinical data as the reference standard were eligible for inclusion. RESULTS: Eleven studies (1,611 patients) were analysed. Based on patient analysis, the sensitivity, specificity, and area under the curve (AUC) of WB-SPECT/CT were 92% (92% con-fidence interval [CI], 89-95%), 95% (95% CI, 94-96%), and 0.9835, respectively, in the case of negative equivocal findings for BM, and 94% (95% CI, 91-96%), 94% (95% CI, 92-95%), and 0.9790, respectively, when regarded positive. On a lesion basis, these parameters were 91% (95% CI, 89-94%), 96% (95% CI, 94-97%), and 0.9906, respectively, in the case negative equivocal findings, and 92% (95% CI, 89-94%), 95% (95% CI, 94-97%), and 0.9898, respectively, when regarded positive. Comparing 1,265 patients from eight studies, higher sensitivity (92% versus 74%, p=0.04) and specificity for WB-SPECT/CT against PBS (93% versus 80%, p=0.01) in the case of positive equivocal findings; however, when regarded negative, WB-SPECT/CT demonstrated higher sensitivity (91% versus 70%, p=0.01), but no significant difference was apparent in specificity (94% versus 89%, p=0.07). CONCLUSION: Compared to PBS, WB-SPECT/CT had superior diagnostic accuracy in BM detection and exhibited a more reliable performance with less equivocal results. (c) 2020 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

aNorthern Ireland Medical Physics Agency bDept of Radiology, Royal Victoria Hospital, Belfast, UK Abstracts of the spring 2005 meeting of the British Nuclear Medicine Society Manchester International Convention Centre, UK; 14–16 March, 2005

To quantify changes in neuronal nAChR binding in vivo, quantitative dynamic SPECT studies were performed with 5-[(123)I]-iodo-A-85380 in baboons pre and post chronic treatment with (-)-nicotine or saline control. Infusion of (-)-nicotine at a dose of 2.0 mg/kg/24h for 14 days resulted in plasma (-)-nicotine levels of 27.3 ng/mL. This is equivalent to that found in an average human smoker (20 cigarettes a day). In the baboon brain the regional distribution of 5-[(123)I]-iodo-A-85380 was consistent with the known densities of nAChRs (thalamus > frontal cortex > cerebellum). Changes in nAChR binding were estimated from the volume of distribution (V(d) ) and binding potential (BP) derived from 3-compartment model fits. In the (-)-nicotine treated animal V(d) was significantly increased in the thalamus (52%) and cerebellum (50%) seven days post cessation of (-)-nicotine treatment, suggesting upregulation of nAChRs. The observed 33% increase in the frontal cortex failed to reach significance. A significant increase in BP was seen in the thalamus. In the saline control animal no changes were observed in V(d) or BP under any experimental conditions. In this preliminary study, we have demonstrated for the first time in vivo upregulation of neuronal nAChR binding following chronic (-)-nicotine treatment.

s: Abstracts of the 30th Annual Scientific Meeting of the Australian and New Zealand Society of Nuclear Medicine

Department of PET and Nuclear Medicine, Royal Prince Alfred Hospital and School of Medical Radiation Technology, University of Sydney, Sydney, NSW, Australia

Meikle, S. R.; Eberl, S.; Kassiou, M.; Robertson, A.; Constable, C.; Forster, J.; Katsifis, A.; Papazian, V.; Birrell, A.; Gillin, A.; Fulham, M. J. Author Information