Orthopedic Department, Shoulder and elbow section, Aarhus University Hospital, Palle Juul Jensens Boulevard 99, 8200, Aarhus, Denmark.
Orthopedic Department, Horsens Regional Hospital, Horsens, Denmark.
Eur J Nucl Med Mol Imaging. 2019 Sep;46(10):2013-2022. doi: 10.1007/s00259-019-04381-w. Epub 2019 Jul 11.
Chronic low-grade periprosthetic joint infection (PJI) of a shoulder replacement can be challenging to diagnose. 18F-FDG PET/CT is suggested as a modality to diagnose lower-limb PJI, but no studies on shoulder replacements exist. The aim of this study was therefore to determine the diagnostic accuracy of 18F-FDG PET/CT in diagnosing chronic PJI of the shoulder.
Patients evaluated for a failed shoulder replacement during a 3-year period were prospectively included in the study. All patients underwent pre-operative 18F-FDG PET/CT, and were evaluated for signs of infection by three independent reviewers using shoulder-specific criteria. Interrater-agreement was calculated between the reviewers. If the patient had revision surgery, biopsy specimens were obtained and cultured with bacterial growth in the cultures serving as gold standard of infection.
A total of 86 patients were included in the study. Nine patients were 18F-FDG PET/CT positive for infection, with only three true positive. Using the gold standard, infection was diagnosed after revision surgery in 22 cases. All infections were chronic and caused by low-virulent microbes. The sensitivity of 18F-FDG PET/CT was 0.14 95% CI (0.03-0.36), specificity 0.91 95% CI (0.81-0.97), positive predictive value was 0.40 95% CI (0.15-0.71) and negative predictive value 0.71 95% CI (0.67-0.75). The inter-observer agreement was 0.56 (Fleiss' kappa), indicating moderate agreement of the visual FDG-PET evaluation using the shoulder-specific criteria.
18F-FDG PET/CT has poor diagnostic accuracy in diagnosing low-grade PJI of the shoulder. 18F-FDG PET/CT cannot be recommended as a part of the routine preoperative workup to diagnose low-grade infection of a shoulder replacement.
慢性低级别假体周围关节感染（PJI）的肩关节置换可能难以诊断。18F-FDG PET/CT 被建议用于诊断下肢 PJI，但尚无关于肩关节置换的研究。因此，本研究旨在确定 18F-FDG PET/CT 诊断慢性肩 PJI 的诊断准确性。
在 3 年期间评估失败的肩部置换的患者前瞻性地纳入本研究。所有患者均进行术前 18F-FDG PET/CT 检查，并由三位独立的评估者使用肩部特异性标准评估感染迹象。评估者之间计算了组内一致性。如果患者进行了翻修手术，则获取活检标本，并进行细菌培养，如果培养物中有细菌生长，则作为感染的金标准。
共有 86 例患者纳入研究。9 例患者 18F-FDG PET/CT 感染阳性，仅有 3 例为真阳性。使用金标准，在翻修手术后诊断出 22 例感染。所有感染均为慢性且由低毒微生物引起。18F-FDG PET/CT 的敏感性为 0.14（95%置信区间 [CI]，0.03-0.36），特异性为 0.91（95%CI，0.81-0.97），阳性预测值为 0.40（95%CI，0.15-0.71），阴性预测值为 0.71（95%CI，0.67-0.75）。观察者间的一致性为 0.56（Fleiss'kappa），表明使用肩部特异性标准对 FDG-PET 视觉评估的一致性为中度。
18F-FDG PET/CT 诊断肩低位 PJI 的诊断准确性较差。18F-FDG PET/CT 不能作为诊断肩置换低级别感染的常规术前检查的一部分。
