From the Department of Radiology.
Division of Surgical Pathology.
J Comput Assist Tomogr. 2022;46(3):455-463. doi: 10.1097/RCT.0000000000001297. Epub 2022 Apr 19.
Magnetic resonance imaging around metal joint prostheses including multiacquisition variable-resonance image combination selective at 1.5 T (from April 2014 to August 2020) was retrospectively evaluated by 2 radiologists for detection of abnormal findings (joint effusion, capsular thickening, pericapsular edema, soft-tissue fluid collection, soft-tissue edema, bone marrow edema pattern around the implant [BME pattern], lymphadenopathy, and others) and overall image impression for PJI. Regarding the soft-tissue fluid collection, presence of communication to the joint or capsular-like structure was evaluated. Clinical assessments were recorded. Positive predictive values (PPVs), negative predictive values (NPVs), and odds ratios (ORs) for PJI were calculated for the abnormal findings. Overall image impression for PJI was evaluated. χ2, Fisher exact, t, and Mann-Whitney U tests and receiver operating characteristic analysis were used. Interobserver agreement was assessed with κ statistics.
Forty-three joints in 36 patients (mean ± SD age, 75.4 ± 8.8 years; 30 women; hip [n = 29], knee [n = 12], and elbow [n = 2]) were evaluated. Eighteen joints (42%) were clinically diagnosed as PJI. The findings suggesting PJI were capsular thickening (PPV, 70%; NPV, 90%; OR, 20.6), soft-tissue fluid collection (PPV, 81%; NPV, 81%; OR, 19.1), soft-tissue edema (PPV, 67%; NPV, 89%; OR, 17), pericapsular edema (PPV, 76%; NPV, 81%; OR, 13.7), and joint effusion (PPV, 55%; NPV, 100%; OR, 12). Soft-tissue fluid collection without capsular-like structure (PPV, 83%; NPV, 74%; OR, 14.4) or with communication to the joint (PPV, 75%; NPV, 71%; OR, 7.3) suggested PJI. The combinations of joint effusion, capsular thickening, pericapsular edema, soft-tissue fluid collection, and soft-tissue edema highly suggested PJI. Regarding the BME pattern, the combination with soft-tissue edema raised the possibility of PJI (PPV, 73%; NPV, 69%; OR, 5.9). Regarding the interobserver agreements for each abnormal finding, κ values were 0.60 to 0.77. Regarding the overall image impression, weighted κ value was 0.97 and areas under the receiver operating characteristic curve were 0.949 (95% confidence interval, 0.893-1.005) and 0.926 (95% confidence interval, 0.860-0.991) with no significant difference (P = 0.534).
The findings suggesting PJI were capsular thickening, soft-tissue fluid collection, soft-tissue edema, pericapsular edema, and joint effusion. The combinations of them highly suggested PJI. Regarding the BME pattern, the combination with soft-tissue edema raised the possibility of PJI.
回顾性分析了 2 位放射科医生在包括多采集可变共振图像组合选择性 1.5T 磁共振成像（2014 年 4 月至 2020 年 8 月）周围金属关节假体的异常发现（关节积液、囊增厚、囊周水肿、软组织积液、软组织水肿、植入物周围骨髓水肿模式[BME 模式]、淋巴结病和其他）和整体印象的 PJI。关于软组织积液，评估是否与关节或囊状结构相通。记录临床评估结果。计算异常发现的 PJI 的阳性预测值（PPV）、阴性预测值（NPV）和比值比（OR）。评估 PJI 的整体印象。使用 χ2、Fisher 精确检验、t 检验和曼-惠特尼 U 检验以及受试者工作特征分析。使用 κ 统计评估观察者间一致性。
36 例患者的 43 个关节（平均±标准差年龄 75.4±8.8 岁；30 名女性；髋关节[29 个]、膝关节[12 个]和肘关节[2 个]）被评估。18 个关节（42%）被临床诊断为 PJI。提示 PJI 的发现包括囊增厚（PPV70%，NPV90%，OR20.6）、软组织积液（PPV81%，NPV81%，OR19.1）、软组织水肿（PPV67%，NPV89%，OR17）、囊周水肿（PPV76%，NPV81%，OR13.7）和关节积液（PPV55%，NPV100%，OR12）。无囊状结构的软组织积液（PPV83%，NPV74%，OR14.4）或与关节相通的软组织积液（PPV75%，NPV71%，OR7.3）提示 PJI。关节积液、囊增厚、囊周水肿、软组织积液和软组织水肿的组合高度提示 PJI。关于 BME 模式，与软组织水肿结合提示 PJI 的可能性（PPV73%，NPV69%，OR5.9）。对于每个异常发现的观察者间一致性，κ 值为 0.60 至 0.77。对于整体图像印象，加权 κ 值为 0.97，受试者工作特征曲线下面积为 0.949（95%置信区间，0.893-1.005）和 0.926（95%置信区间，0.860-0.991），无显著性差异（P=0.534）。
提示 PJI 的发现包括囊增厚、软组织积液、软组织水肿、囊周水肿和关节积液。它们的组合高度提示 PJI。关于 BME 模式，与软组织水肿结合提示 PJI 的可能性。
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