Department of Biomedical Sciences, Humanitas University, Pieve Emanuele, Milan, Italy.
Department of Radiology, Humanitas Clinical and Research Center- IRCCS, Rozzano, Milan, Italy.
Eur J Nucl Med Mol Imaging. 2019 Jul;46(8):1605-1615. doi: 10.1007/s00259-019-04336-1. Epub 2019 May 1.
Complete fracture healing is crucial for positive patient outcome. A major complication in fracture treatment is non-union. Infection is among the main causes of non-union and hence of osteosynthesis failure. For the treatment of non-union, it is crucial to understand whether a fracture is not healing because of an underlying septic process, since the surgical approach to non-unions definitely differs according to whether the fracture is infected or aseptic. We aimed to assess the diagnostic performance of 2-deoxy-2-[F]fluoro-D-glucose positron emission tomography-computed tomography ([F]FDG PET/CT) in the evaluation of infection as possible cause of non-union.
We retrospectively evaluated images of 47 patients treated in our trauma center who, between January 2011 and June 2017, underwent preoperative [F]FDG PET/CT aiming to exclude infection in non-union. Clinical data, diagnostic examinations, laboratory and microbiology results, and patient outcome were collected and analyzed. [F]FDG PET/CT images were visually and semiquantitatively evaluated using the maximum standardized uptake value (SUV). Imaging findings, as assessed by an experienced nuclear medicine physician and an experienced musculoskeletal radiologist, were compared with intraoperative microbiological culture results, which were used for final diagnosis (reference standard). The diagnostic performance of [F]FDG PET/CT in detecting infected non-union was assessed.
Twenty-two patients were not infected, while the remaining 25 had positive intraoperative microbiological results. C-reactive protein (CRP) was within the normal range in 13 cases (five with a final diagnosis of infection) and higher than normal in 25 patients (13 with a final diagnosis of infection). Infection was correctly detected on visual analysis of PET/CT images in 23 cases, while 2/25 infected patients had no significant [F]FDG uptake and were considered false negatives. In seven cases, [F]FDG PET/CT showed false positive results; 15/22 disease-free patients were correctly diagnosed. The diagnostic accuracy of [F]FDG PET/CT in the final diagnosis of infection was 81% (38/47); its sensitivity, specificity, positive predictive value, and negative predictive value were 92%, 68%, 77%, and 88% respectively. The likelihood ratio for a positive test (LR+) was 2.89 and for a negative test, 0.12. Pretest probability of disease was 53%. Post-test probability based on LR+ was 77%.
[F]FDG PET/CT is a promising tool for diagnoses of infected non-unions. Both PET and CT images should be interpreted to achieve a high sensitivity (92%) and a very good negative post-test probability (12%).
完全骨折愈合对于患者的积极预后至关重要。骨折治疗的主要并发症是骨折不愈合。感染是骨折不愈合的主要原因之一，也是内固定失败的主要原因。对于骨折不愈合的治疗，了解骨折是否因潜在的感染过程而不愈合至关重要，因为根据骨折是否感染，非感染性，手术方法肯定会有所不同。我们旨在评估 2-脱氧-2-[F]氟-D-葡萄糖正电子发射断层扫描-计算机断层扫描（[F] FDG PET / CT）在评估感染作为骨折不愈合的可能原因方面的诊断性能。
我们回顾性评估了 2011 年 1 月至 2017 年 6 月期间在我们的创伤中心接受术前[F] FDG PET / CT 检查以排除骨折不愈合感染的 47 例患者的图像。收集并分析了临床数据，诊断检查，实验室和微生物学结果以及患者的预后。使用最大标准化摄取值（SUV）对[F] FDG PET / CT 图像进行视觉和半定量评估。由经验丰富的核医学医师和经验丰富的肌肉骨骼放射科医师评估成像结果，并与术中微生物培养结果进行比较，后者用于最终诊断（参考标准）。评估了[F] FDG PET / CT 检测感染性骨折不愈合的诊断性能。
22 例患者未感染，而其余 25 例患者术中微生物学结果阳性。在 13 例（最终诊断为感染的 5 例）中 C-反应蛋白（CRP）在正常范围内，在 25 例患者中CRP 高于正常值（最终诊断为感染的 13 例）。在 23 例中，PET / CT 图像的视觉分析正确检测到感染，而 2/25 例感染患者没有明显的[F] FDG摄取，被认为是假阴性。在七种情况下，[F] FDG PET / CT 显示出假阳性结果；22/22 例无疾病患者的诊断正确。[F] FDG PET / CT 在感染最终诊断中的准确性为 81％（47/47）；其敏感性，特异性，阳性预测值和阴性预测值分别为 92％，68％，77％和 88％。阳性试验（LR +）的可能性比为 2.89，阴性试验的可能性比为 0.12。疾病的术前可能性为 53％。基于 LR +的测试后概率为 77％。
[F] FDG PET / CT 是诊断感染性骨折不愈合的有前途的工具。为了获得高敏感性（92％）和非常好的阴性测试后概率（12％），应解释 PET 和 CT 图像。
