^(18)F-FDGPET/CT早期动态显像与常规显像诊断下肢骨折内固定术后感染的价值

The Value of Early Dynamic and Conventional Whole-body^(18)F-FDG PET/CT in Diagnosing the Infection After Internal Fixation of Lower Limb Fracture

目的:利用^(18)F-氟代脱氧葡萄糖(^(18)F-FDG)正电子发射计算机体层成像(PET/CT)早期动态灌注成像技术结合传统常规显像,评估^(18)F-FDG灌注与代谢参数在下肢骨折内固定术后感染中的应用价值。方法:前瞻性纳入下肢骨折内固定术后愈合不良患者40例,其中男28例,女12例,年龄(40.0±14.0)岁。以病理及细菌培养结果作为术后感染的金标准。对^(18)F-FDGPET/CT早期动态显像进行重建处理得到时间放射性曲线,分析骨折部位最大标准摄取值(SUV_(max))的达峰时间、早期动态显像峰值(EDSUV_(max))、达峰速率。常规显像获得骨折部位SUV_(max)值及靶本底比值(TBR)。通过受试者工作特征(ROC)曲线分别获得EDSUV_(max)值与常规显像SUVmx值诊断下肢骨折内固定术后感染的最佳阈值,并计算诊断效能。结果:在早期动态显像中,下肢骨折内固定术后感染者骨折部位EDSUV_(max)值为5.3(4.1,8.0),高于单纯骨折愈合不良者的4.0(3.0,5.5),差异有统计学意义(P<0.05)。感染者达峰时间缩短、峰时提前,在时间放射性曲线中,感染者均表现为早期达峰后下降,而单纯骨折愈合不良者为持续上升型曲线。在常规显像中,下肢骨折内固定术后感染者骨折部位SUVmx值、TBR值分别为11.2(6.0,14.0)、4.97(2.90,7.30),均高于单纯骨折愈合不良者的4.80(3.25,7.05)、2.80(2.39,4.00),差异有统计学意义(P<0.05)。ROC曲线分析获得EDSUVmx值与常规显像SUV_(max)值诊断下肢骨折内固定术后感染的最佳界值分别为6.5和8.1,获得的灵敏度分别为42.1%、63.2%,特异度分别为100%、90.5%。结论:早期动态与常规"8F-FDGPET/CT显像诊断下肢骨折内固定术后感染效能大致相当,早期动态显像获得的时间放射性曲线特点有助于进一步明确下肢骨折内固定术后感染的诊断。

Purpose:To evaluate the diagnostic value of the perfusion and metabolism parameters in the infection after internal fixation of lower limb fracture by combining the early dynamic^(18)F-fluorode-oxyglucose(^(18)F-FDG)positron emission tomography and computed tomography(PET/CT)and conventional static imaging.Methods:A total of 40 patients[28 males,12 females,with an average of(40.0±14.0)years]were included in this prospective study.The final diagnosis was made by the pathology and bacterial culture results.The early dynamic^(18)F-FDG PET/CT was used to acquire time activity curve(TAC)and dynamic imaging data,including peak early dynamic(ED)SUV_(max)s time to peak and rate-to peak ED SUV_(max)-The SUV_(max)of fracture point and the target-to-background ratio(TBR)was obtained by the conventional^(18)F-FDG PET/CT.The ED SUV_(max)and SUV_(max)cutoff value in detection of the infection after internal fixation of lower limb fracture was determined by the ROC curve,and the diagnostic efficiencies were calculated.Results:In the early dynamic imaging,the ED SUV_(max)of the lower limb post internal fixation operative infection was 5.3(4.1,8.0),which was significantly higher than that of 4.0(3.0,5.5)for the malunion group,respectively(P<0.05).Infections groups showed time to peak was shorter than the malunion group.The TAC of the infection group showed that ED SUVmx declined after the peak,while the malunion groups rose continuously without declining.In the conventional static imaging,the SUV_(max)and TBR of the infection after internal fixation of lower limb fracture were 11.2(6.0,14.0)and 4.97(2.90,7.30),which were also significantly higher than that of malunion group[4.80(3.25,7.05)and 2.80(2.39,4.00),respectively](P<0.05).The cutoff values were 6.5 and 8.1 for the ED SUV_(max)and conventional SUV_(max)to diagnose the infection after internal fixation of lower limb fracture.The diagnostic sensitivity were 42.1%and 63.2%,and the specificity were 100%and 90.5%.Conclusion:There was no significant difference in the diagnostic performances between the early dynamic IsF-FDG PET/CT and conventional 18F-FDG PET/CT in detecting the infection after internal fixation of lower limb fracture.The TAC curve and time to peak from the early dynamic isF-FDG PET/CT could help to confirm the diagnosis of the infection after internal fixationof lower limb fracture.