目的:探讨n 18F-脱氧葡萄糖(n 18F-FDG)正电子发射计算机断层显像(PET)/CT脑代谢显像在颅内原发性中枢神经系统淋巴瘤中的影像学特征及诊断价值。n 方法:选取2012年3月至2020年1月北部战区总医院核医学科收治的74例疑似颅内原发性中枢神经系统淋巴瘤(PCNSL)的患者。男48例，女26例，年龄(62.3±10.6)岁，年龄范围为24～85岁。以最终病理结果为“金标准”，总结颅内PCNSL患者n 18F-FDG PET/CT的图像特征，并比较n 18F-FDG PET/CT与MRI在颅内PCNSL中的诊断效能。采用Fisher精确检验分析数据，并应用受试者操作特征(ROC)曲线对PCNSL患者的最大标准摄取值(SUVmax)进行分析，确定最佳诊断阈值。n 结果:病理结果显示，74例疑似PCNSL患者中，53例确诊为PCNSL。n 18F-FDG PET/CT准确诊断52例，误诊1例；21例非PCNSL患者中，n 18F-FDG PET/CT排除19例，不确定诊断2例。MRI准确诊断出34例，误诊19例；21例非PCNSL患者中，MRI排除8例，诊断不确定13例。n 18F-FDG PET/CT与MRI对PCNSL的灵敏度、特异度、准确度、阳性预测值、阴性预测值分别为98.1%(52/53)、90.5%(19/21)、95.9%(71/74)、96.3%(52/54)、95.0%(19/20)及64.2%(34/53)、38.1%(8/21)、56.8%(42/74)、72.3%(34/47)、29.6%(8/27)。n 18F-FDG PET/CT与MRI的诊断准确性比较，差异有统计学意义(n P<0.001)。53例PCNSL患者共72处病灶，所有病灶n 18F-FDG放射性摄取均明显增高，4处病灶放射性摄取环形不均匀增高，1处病灶放射性摄取马蹄形增高，余病灶放射性摄取均为结节状及团块状增高，病灶周围见轻中度水肿带，SUVmax为18.1±6.1，SUVmax范围为10.5～38.8。应用ROC曲线分析SUVmax诊断颅内PCNSL的最佳截断值为14.2。n 结论:颅内PCNSL的n 18F-FDG PET/CT图像有一定的特征性，n 18F-FDG PET/CT在其定位诊断中具有非常重要的价值，半定量指标SUVmax有助于PCNSL的诊断。n “,”Objective:To investigate the diagnostic value of 18-fluorine flurode oxyglucos(n 18F-FDG)positron emission tomography(PET)/CT in intracranial primary central nervous system lymphoma(PCNSL).n Methods:A retrospective study was performed on 74 patients with clinically suspected intracranial PCNSL who were admitted to the General Hospital of Northern Theater Command from March 2012 to January 2020.There were 48 males and 26 females, aged(62.3±10.6)years old, ranging from 24 to 85 years old.Using the final pathological results as the gold standard, the imaging characteristics of n 18F-FDG PET/CT in intracranial PCNSL patients were summarized, and the diagnostic efficacy of n 18F-FDG PET/CT and MRI in intracranial PCNSL were compared.Fisher′s exact test was used to analyze the data, and the receiver operating characteristic curve(ROC curve)was applied to analyze the SUVmax of PCNSL patients to determine the optimal diagnostic threshold.n Results:Pathological results showed that of the 74 suspected PCNSL patients, 53 were confirmed as PCNSL.The 52 cases were accurately diagnosed by n 18F-FDG PET/CT, and 1 case was misdiagnosed.Among the 21 non-PCNSL patients, 19 were excluded by n 18F-FDG PET/CT, and 2 were indeterminate.MRI accurately diagnosed 34 cases and misdiagnosed 19 cases.Among the 21 non-PCNSL patients, 8 were excluded by MRI and 13 were diagnosed indeterminate.The sensitivity, specificity, accuracy, positive predictive value and negative predictive value of n 18F-FDG PET/CT and MRI for PCNSL were 98.1%(52/53), 90.5%(19/21), 95.9%(71/74), 96.3%(52/54), 95.0%(19/20)and 64.2%(34/53), 38.1%(8/21), 56.8%(42/74), 72.3%(34/47), 29.6%(8/27).n 18F-FDG PET/CT and MRI, the diagnosis of intracranial PCNSL accuracy difference was statistically significant(n P<0.001). The 53 PCNSL patients had a total of 72 lesions, the radiation uptake ofn 18F-FDG in all the lesions was significantly increased, with uneven ring uptake in 4 cases, horseshoe uptake in 1 case, nodular and mass uptake in the remaining lesions, mild and moderate edema zone around the lesions, SUVmax was 18.1±6.1, SUVmax range of 10.5 to 38.8.ROC curve analysis showed that the best cut-off value of SUVmax in the diagnosis of intracranial PCNSL was 14.2.n Conclusion:The n 18F-FDG PET/CT images of intracranial primary central nervous system lymphoma have certain characteristics, and n 18F-FDG PET/CT has a very important value in its localization diagnosis, and the semi-quantitative indicator SUVmax is helpful for the diagnosis of PCNSL.n