Campagna Giuseppe, Lauri Chiara, Manta Ringo, Ottaviani Roberta, Vella Walter Davide, Signore Alberto
Department of Medical-Surgical Sciences and of Translational Medicine, Sant'Andrea Hospital, "Sapienza" University of Rome, 00161 Rome, Italy.
Department of Nuclear Medicine, Université Libre de Bruxelles, 1050 Brussels, Belgium.
Diagnostics (Basel). 2024 Sep 14;14(18):2043. doi: 10.3390/diagnostics14182043.
White blood cell (WBC) scintigraphy plays a major role in the diagnostic approach to periprosthetic infections. Although the procedure has been standardized by the publication of several guidelines, the interpretation of this technique may be susceptible to intra and inter-variability. We aimed to assess the reproducibility of interpretation between nuclear medicine physicians and by the same physician and to demonstrate that Cohen's coefficient is more unstable than Gwet's coefficient, as the latter is influenced by the prevalence rates. We enrolled 59 patients who performed a Technetium-99m WBC (Tc-WBC) scintigraphy for suspected hip or knee prosthesis infection. Three physicians, blinded to all patient clinical data, performed two image readings. Each WBC study was assessed both visually and semi-quantitatively according to the guidelines of the European Association of Nuclear Medicine (EANM). For semi-quantitative analysis, readers drew an irregular Region of Interest (ROI) over the suspected infectious lesion and copied it to the normal contralateral bone. The mean counts per ROI were used to calculate lesion-to-reference tissue (LR) ratios for both late and delayed images. An increase in LR over time (LRlate> LRdelayed) of more than 20% was considered indicative of infection. Agreement between readers and between readings was assessed by the first-order agreement coefficient (Gwet's AC). Reading time for each scan was compared between the three readers in both the first and the second reading, using the Generalized Linear Mixed Model. An excellent agreement was found among all three readers: 0.90 for the first reading and 0.94 for the second reading. Both inter- and intra-variability showed values ≥0.86. Gwet's method demonstrated greater robustness than the Cohen coefficient when assessing the intra and inter-rater variability, since it is not influenced by the prevalence rate. These studies can contribute to improving the reliability of nuclear medicine imaging techniques and to evaluating the effectiveness of trainee preparation.
白细胞（WBC）闪烁扫描在人工关节周围感染的诊断方法中起着重要作用。尽管该检查程序已通过多项指南的发布实现标准化，但这项技术的解读可能容易受到内部和外部变异性的影响。我们旨在评估核医学医师之间以及同一位医师对结果解读的可重复性，并证明科恩系数比格韦特系数更不稳定，因为后者受患病率的影响。我们招募了59例因疑似髋或膝关节假体感染而进行锝-99m白细胞（Tc-WBC）闪烁扫描的患者。三位对所有患者临床数据不知情的医师进行了两次图像解读。每项白细胞检查均根据欧洲核医学协会（EANM）的指南进行了视觉和半定量评估。对于半定量分析，读者在疑似感染病灶上绘制一个不规则的感兴趣区域（ROI），并将其复制到对侧正常骨上。利用每个ROI的平均计数计算晚期和延迟图像的病灶与参考组织（LR）比值。LR随时间增加（LR晚期>LR延迟）超过20%被认为提示感染。通过一阶一致性系数（格韦特AC）评估读者之间以及不同次解读之间的一致性。在第一次和第二次解读中，使用广义线性混合模型比较三位读者对每次扫描的阅读时间。三位读者之间均发现了极佳的一致性：第一次解读为0.90，第二次解读为0.94。内部和外部变异性的值均≥0.86。在评估评分者内部和评分者之间的变异性时，格韦特方法比科恩系数表现出更强的稳健性，因为它不受患病率的影响。这些研究有助于提高核医学成像技术的可靠性，并评估实习生培训的效果。
