自身免疫性脑炎儿童伴癫痫发作且MRI阴性的^(18)F-FDG PET/CT半定量分析诊断模型优化研究

Optimization of ^(18)F-FDG PET/CT semi-quantitative diagnostic model for children with autoimmune encephalitis with epilepsy and negative MRI

目的探讨^(18)F-FDG PET/CT显像在癫痫发作且MRI阴性的疑似自身免疫性脑炎(AE)患儿中的诊断价值。方法回顾性分析2019年5月至2022年8月期间在上海交通大学医学院附属新华医院有癫痫发作症状且MRI阴性的94例临床疑似AE患儿(男49例、女45例;年龄1~15岁)。所有患儿行^(18)F-FDG PET/CT脑显像,按临床最终诊断分为AE组与非AE组,并评估其^(18)F-FDG PET/CT视觉诊断的效能。评估所有患儿皮质病灶范围评分(S),测量皮质病灶(L)、基底节(B)和丘脑(T)的SUVmax、SUVmean和最小SUV(SUVmin),获得L/B、L/T的各SUV比值(SUVR)。采用两独立样本t检验和Mann-Whitney U检验分析数据,采用二元logistic回归分析确定AE的独立预测因素,并建立诊断模型。通过ROC曲线分析和Delong检验评价诊断效能。结果AE组53例,非AE组41例。^(18)F-FDG PET/CT视觉分析诊断AE的灵敏度为100%(53/53),特异性为43.9%(18/41),准确性为75.5%(71/94)。LSUVmax、LSUVmean、LSUVmin、L/BSUVRmax、L/BSUVRmean、L/BSUVRmin、L/TSUVRmax、L/TSUVRmean、L/TSUVRmin和S在AE组和非AE组间差异具有统计学意义(z=-6.74,t值:-8.51~-3.97,均P<0.001)。ROC曲线分析示参数L/BSUVRmax的AUC最高(0.914)。Logistic回归分析示,S[比值比(OR)=11.40,95%CI:2.18~59.52,P=0.004]、L/BSUVRmax(OR=13.19,95%CI:2.11~82.51,P=0.006)和L/TSUVRmax(OR=9.66,95%CI:1.57~59.55,P=0.015)是AE的独立影响因素。建立诊断模型:P=1/(1+e-x),x=2.433×S+2.580×L/BSUVRmax+2.267×L/TSUVRmax-3.802。该模型的AUC为0.948,其诊断AE的灵敏度、特异性和准确性分别为98.1%(52/53)、90.2%(37/41)和94.7%(89/94);优化后的评分系统诊断效能与优化前的模型一致,且均优于L/BSUVRmax(z值:2.01和2.01,P值:0.040和0.040)。结论基于^(18)F-FDG PET/CT半定量分析建立的诊断模型和评分系统对儿童AE有较好的诊断效能,且优于单独的半定量参数。

Objective To investigate the value of ^(18)F-FDG PET/CT imaging in the diagnosis of suspected autoimmune encephalitis(AE)in children with epilepsy and negative MRI.Methods From May 2019 to August 2022,94 suspected AE children(49 males,45 females;age 1-15 years)with epilepsy and negative MRI who underwent brain ^(18)F-FDG PET/CT imaging at Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine were retrospectively analyzed.All patients were divided into AE and non-AE groups based on clinical final diagnosis.The effectiveness of visual diagnosis was evaluated.The cortical lesion extent score(S),and SUVmax,SUVmean and minimum of SUV(SUVmin)of cortical lesions(L),basal ganglia(B)and thalamus(T)were measured and SUV ratios(SUVR)of L/B or L/T were obtained.Independent-sample t test or Mann-Whitney U test was used to analyze data.Binary logistic regression analysis was used to screen the diagnostic factors of AE,and a diagnostic model was established.The diagnostic efficiency was evaluated by ROC curve analysis and Delong test.Results There were 53 cases in AE group and 41 cases in non-AE group.Based on visual analysis,the sensitivity,specificity and accuracy of ^(18)F-FDG PET/CT for AE were 100%(53/53),43.9%(18/41)and 75.5%(71/94),respectively.Differences of LSUVmax,LSUVmean,LSUVmin,L/BSUVRmax,L/BSUVRmean,L/BSUVRmin,L/TSUVRmax,L/TSUVRmean,L/TSUVRmin and S between AE and non-AE groups were statistically significant(z=-6.74,t values:from-8.51 to-3.97,all P<0.001).ROC curve analysis showed that the AUC of L/BSUVRmax was the highest(0.914)among visual analysis and semi-quantitative parameters.Logistic regression analysis showed that S(odds ratio(OR)=11.40,95%CI:2.18-59.52,P=0.004),L/BSUVRmax(OR=13.19,95%CI:2.11-82.51,P=0.006)and L/TSUVRmax(OR=9.66,95%CI:1.57-59.55,P=0.015)were independent diagnostic factors for AE.Regression model was established:P=1/(1+e-x),x=2.433×S+2.580×L/BSUVRmax+2.267×L/TSUVRmax-3.802.The AUC of this model was 0.948,with the sensitivity,specificity and accuracy of 98.1%(52/53),90.2%(37/41)and 94.7%(89/94),respectively.The diagnostic efficacy of the optimized scoring system was consistent with the pre-optimization model,and were both superior to L/BSUVRmax(both z=2.01,both P=0.040).Conclusion The diagnostic model and scoring system based on the semi-quantitative analysis of ^(18)F-FDG PET/CT have better diagnostic efficacy for AE and are superior to semi-quantitative parameters alone.