Purpose: This study aimed to assess the diagnostic performances of multimodal imaging [i.e., white blood cell single-photon emission computed tomography/CT (^99mTc-HMPAO-WBC SPECT/CT) and 18-fluoride-fluorodeoxyglucose positron emission tomography/CT ([¹⁸F]FDG PET/CT)] in patients with suspected infection after the Bentall procedure, proposing new specific diagnostic criteria for the diagnosis.

Methods: Between January 2009 and December 2019, we selected within a cardiovascular infections registry, 76 surgically treated patients (27 women and 49 men, median 66 years, and range 29–83 years). All the patients underwent molecular imaging for a suspected infection after the replacement of the aortic valve and ascending aorta according to the Bentall procedure. We analyzed 98 scans including 49 ^99mTc-WBC and 49 [¹⁸F]FDG PET/CT. A total of 22 patients with very early/early suspected infection (<3 months after surgery) were imaged with both the techniques. Positive imaging was classified according to the anatomical site of increased uptake: to the aortic valve (AV), to both the AV and AV tube graft (AVTG) or to the TG, to surrounding tissue, and/or to extracardiac sites (embolic events or other sites of concomitant infection). Standard clinical workup included in all the patients having echocardiography/CT, blood culture, and the Duke criteria. Pretest probability and positive/negative likelihood ratio were calculated. Sensitivity and specificity of ^99mTc labeled hexamethylpropylene amine oxime-WBC SPECT/CT (^99mTc-HMPAO-WBC SPECT/CT) and [¹⁸F]FDG PET/CT imaging were calculated by using microbiology (n = 35) or clinical follow-up (n = 41) as final diagnosis. ^99mTc-HMPAO-WBC scintigraphy and [¹⁸F]FDG PET/CT findings were compared with 95% CIs by using the McNemar test to those of echocardiography/CT, blood culture, and the Duke criteria.

Results: Sensitivity, specificity, and accuracy of ^99mTc-HMPAO-WBC were 86, 92, and 88%, respectively, with a slightly higher sensitivity for tube graft infection (TGI) as compared to isolated AV and combined AVTG. Overall, sensitivity, specificity, and accuracy of [¹⁸F]FDG PET/CT were 97, 73, and 90%, respectively. In 22 patients with suspected very early and early postsurgical infections, the two imaging modalities were concordant in 17 cases [10 true positive (TP) and 7 true negative (TN)]. [¹⁸F]FDG PET/CT presented a higher sensitivity than ^99mTc-HMPAO-WBC scan. ^99mTc-HMPAO-WBC scan correctly classified as negative three false-positive (FP) PET/CT findings.

Conclusion: Our findings supported the use of ^99mTc-HMPAO-WBC SPECT/CT and [¹⁸F]FDG PET/CT in patients with suspicion infection after the Bentall procedure early in the course of the disease onset to confirm the diagnosis and provide a comprehensive assessment of disease burden through the proposed criteria.

目的：本研究旨在评估多模态成像 [即，白细胞单光子发射计算机断层扫描/CT ( ^99m Tc-HMPAO-WBC SPECT/CT) 和 18-氟化物-氟脱氧葡萄糖正电子发射断层扫描/CT ([ ¹⁸ F]FDG PET/CT)] 在 Bentall 手术后疑似感染的患者中，提出了新的具体诊断标准。

方法：2009 年 1 月至 2019 年 12 月期间，我们在心血管感染登记处选择了 76 名接受手术治疗的患者（27 名女性和 49 名男性，中位年龄为 66 岁，范围为 29-83 岁）。所有患者在根据 Bentall 手术置换主动脉瓣和升主动脉后，均对疑似感染进行了分子影像学检查。我们分析了 98 次扫描，包括 49 ^99m Tc-WBC 和 49 [ ¹⁸F]FDG PET/CT。共有 22 名非常早期/早期疑似感染（手术后 <3 个月）的患者使用这两种技术进行了成像。根据摄取增加的解剖部位对阳性成像进行分类：主动脉瓣 (AV)、AV 和 AV 管移植物 (AVTG) 或 TG、周围组织和/或心外部位（栓塞事件或其他伴随感染的部位）。标准临床检查包括所有具有超声心动图/CT、血培养和杜克标准的患者。计算前测概率和阳性/阴性似然比。^99m Tc 标记的六甲基丙烯胺肟-WBC SPECT/CT ( ^99m Tc-HMPAO-WBC SPECT/CT) 和 [ ^{18 的}灵敏度和特异性F]FDG PET/CT 成像使用微生物学计算（n = 35) 或临床随访 (n= 41) 作为最终诊断。^99m Tc-HMPAO-WBC 闪烁扫描和 [ ¹⁸ F] FDG PET/CT 结果与 95% CIs 通过使用 McNemar 测试与超声心动图/CT、血培养和杜克标准的结果进行比较。

结果：^99m Tc-HMPAO-WBC 的敏感性、特异性和准确性分别为 86%、92% 和 88%，与分离的 AV 和联合 AVTG 相比，对移植管感染 (TGI) 的敏感性略高。总体而言，[ ¹⁸ F]FDG PET/CT 的敏感性、特异性和准确性分别为 97%、73% 和 90%。在疑似极早期和早期术后感染的 22 例患者中，17 例两种影像学检查结果一致 [10 例真阳性 (TP) 和 7 例真阴性 (TN)]。[ ¹⁸ F]FDG PET/CT 表现出比^99m Tc-HMPAO-WBC 扫描更高的灵敏度。^99m Tc-HMPAO-WBC 扫描正确分类为阴性三个假阳性 (FP) PET/CT 结果。

结论：我们的研究结果支持在疾病早期在 Bentall 手术后怀疑感染的患者中使用^99m Tc-HMPAO-WBC SPECT/CT 和 [ ¹⁸ F]FDG PET/CT 以确认诊断并提供全面评估疾病负担的建议标准。