^(11)C-MET PET/CT诊断脑胶质瘤术后复发残留的初步研究

A preliminary study of ^(11)C-methionine PET/CT in diagnosis of recurrence or residue after glioma surgery

目的探讨^(11)C标记的蛋氨酸(^(11)C-methionine,^(11)C-MET)PET/CT在诊断脑胶质瘤术后复发残留的应用价值。方法回顾性分析因胶质瘤术后行CT或MRI检查可疑术后复发残留的患者17例。患者均行^(11)C-MET PET/CT检查,均经二次手术病理或临床随访证实为脑胶质瘤术后复发残留(postoperative relapse and residue, PORR)或治疗后相关良性病变(therapy-related benign changes, TRBC)。双盲法由2名>5年PET/CT诊断经验的医师测量病灶最大标准摄取值(maximum standardized uptake value,SUV_(max))及靶/本底比值(target/normal background ratio,T/N:病灶SUV_(max)/对侧正常额叶SUV_(mean))并作出定性诊断。比较2位医师之间病灶半定量测量和定性诊断的一致性。计算^(11)C-MET PET/CT诊断胶质瘤术后复发残留的敏感度、特异度和准确率。比较PORR组与TRBC组SUV_(max)及T/N值的差异。胶质瘤PORR组病灶SUV_(max)及T/N值与胶质瘤WHO初次手术病理分级行相关分析。结果在半定量测量方面(SUV_(max)及T/N值),2位医师测量值比较,差异均无统计学意义(均P>0.05);在定性诊断上,2名医师诊断一致率为100%。17例胶质瘤术后患者中,PORR 14例,TRBC 3例。^(11)C-MET PET/CT诊断胶质瘤术后复发的敏感度85.7%(12/14),特异度为100%(3/3),准确率88.2%(15/17)。PORR组与TRBC组SUV_(max)及T/N值比较,差异均具有统计学意义(均P<0.05)。14例胶质瘤术后复发残留患者中WHO分级Ⅰ级1例,Ⅱ级6例,Ⅲ级5例,Ⅳ级2例。复发残留病灶的SUV_(max)与T/N值有相关性(r=0.86,P<0.01);SUV_(max)与肿瘤WHO分级无相关性(r=0.102,P=0.728);T/N值与肿瘤WHO分级无相关性(r=0.056,P=0.848)。结论 ^(11)C-MET PET/CT能清楚显示复发残留病灶,不同医师之间诊断有很高的一致性,诊断准确率高,易于胶质瘤术后复发残留的检出。病灶的^(11)C-MET摄取程度与肿瘤分级无相关性,有利于低级别肿瘤复发的检出。

Objective To evaluate the value of ^(11) C-methionine(MET)PET/CT in the diagnosis of postoperative recurrence or residue of brain glioma.Methods A retrospective analysis was performed on 17 patients who underwent CT or MRI examination for suspected postoperative recurrence or residue due to glioma.^(11) C-MET PET/CT was performed.All the patients were confirmed to have postoperative recurrence or residue(PORR)or therapy-related benign changes(TRBC)of brain glioma via the pathology of second operation or clinical follow-up.The maximum standardized uptake value(SUVmax)and target/nomal background ratio(T/N):lesion SUVmax/contralateral normal frontal lobe SUVmean)values were measured by two doctors with more than 5 years of diagnostic experience in PET/CT,and qualitative diagnosis was made.The consistency of semi-quantitative measurement and qualitative diagnosis was compared between the two doctors.The sensitivity,specificity and accuracy of ^(11) C-MET PET/CT in the diagnosis of postoperative recurrence and residue were calculated.The differences of SUVmax value and T/N ratio between the PORR group and TRBC group were compared.Correlation analysis was performed between the value of SUVmax and T/N of the lesion and the primary operative pathological tumor grade in the PORR group.Results In terms of the semi-quantitative measurement(SUVmax value and T/N ratio),there were no significant differences between the measurement values of doctor 1 and doctor 2(both P>0.05).In terms of qualitative diagnosis,the diagnosis consistency rate between the two doctors was 100%.There were 17 patients with glioma,14 in the PORR group and 3 in the TRBC group.The sensitivity,specificity and accuracy of ^(11) C-MET PET/CT in the diagnosis of postoperative recurrence or residue of glioma were 85.7%(12/14),100%(3/3),and 88.2%(15/17).SUVmax and T/N were statistically different between the PORR group and TRBC group(both P<0.05).Of the 14 patients in the PORR group,there was 1 patient in tumor gradeⅠ,6 patients in gradeⅡ,5 patients in gradeⅢ,and 2 patients in gradeⅣ.SUVmax value of relapse or residual lesions was correlated with T/N ratio(r=0.86,P<0.01).There was no correlation between SUVmax value and tumor grade(r=0.102,P=0.728),and between T/N ratio and tumor grade(r=0.056,P=0.848).Conclusions ^(11) C-MET PET/CT can clearly show relapse or residual lesions with high consistency of diagnosis among different doctors.The diagnosis accuracy is high and it is easy to detect the recurrence and residual lesions of glioma after operation.The MET uptake levels of the lesions are not correlated with the tumor grade,which are beneficial to the detection of low-grade tumor recurrence or residue.