【作者】 吴敏；

【导师】 林承赫；

【作者基本信息】 吉林大学 ， 影像医学与核医学（专业学位）， 2015， 硕士

【摘要】 目的：通过分析18F-FDG PET/CT在PCNSL中诊断效能，评价18F-FDGPET/CT在PCNSL诊断方面的临床应用价值，为PCNSL的早期诊断提供科学规范的手段。方法：1、病例来源于在本院行18F-FDG PET/CT显像的40例患者，包括10例PCNSL患者、18例脑胶质瘤患者及12例脑转移瘤患者，共计78个病灶，所有病例均经病理学或临床随访确诊。2、显像仪器为德国Siemens Discovery16HR PET/CT扫描仪。先行螺旋CT扫描，采集条件：管电压120kV，管电流80mA，球管单圈旋转时间0.4s，层厚3.75mm。PET采集选用三维采集模式，取6～8个床位，胸腹部每个床位2min，脑每个床位5min。扫描结束后计算机对PET图像衰减校正，校正后的PET图像和CT图像的重建和融合由计算机软件自动完成，融合完成后可分别得到CT、PET和PET/CT图像。由2-3名有经验的核医学科医生与影像科医生对显像结果进行共同判读。3、根据78个病灶的18F-FDG PET/CT显像结果进行分析，归纳总结PCNSL18F-FDG PET/CT影像表现特点。4、最大标准化摄取值（maximum standardized uptake value，SUVmax）和平均标准化摄取值（mean standardized uptake value，SUVmean）为本研究18F-FDG PET/CT中PET诊断的两个主要参数。观察78个病灶的SUVmax和SUVmean的统计分布，分析PCNSL与脑胶质瘤和脑转移瘤SUVmax和SUVmean的组间差异；利用接受者操作特性曲线(receiver operatingcharacteristics curve，ROC曲线)计算SUVmax及SUVmean诊断PCNSL的最佳阈值，评价两个PET参数的诊断价值。5、统计学处理应用SPSS18.0统计软件进行数据分析。PCNSL、脑胶质瘤及脑转移瘤病灶中放射性浓聚程度SUVmax及SUVmean以x±s表示，组间比较采用独立样本t检验；用ROC曲线分析SUVmax和SUVmean在PCNSL诊断中的最佳阈值，应用ROC曲线下面积分别评价SUVmax及SUVmean的诊断效能。结果：1、PCNSL以多发为主，好发于幕上，多位于大脑深部，18F-FDG放射性摄取显著增高，病灶内示踪剂摄取多均匀，病灶内部出血、坏死、囊变及钙化少见，瘤周水肿少见，以轻中度水肿为主。2、PCNSL组SUVmax（16.64±6.07）高于胶质瘤组SUV max（11.47±5.89），两组数据有显著性差异（t=2.996，p＜0.01）；PCNSL组SUVmax（16.64±6.07）高于及脑转移瘤组SUV max（9.98±5.25），两组数据有显著性差异（t=4.143，p＜0.01）3、PCNSL组SUVmean（13.99±5.54）高于胶质瘤组SUVmean（8.78±4.82），两组数据有显著性差异（t=3.505，p＜0.01）；PCNSL组SUVmean（13.99±5.54）高于及脑转移瘤组SUVmean（7.24±4.04），两组数据有显著性差异（t=4.985，p＜0.01）。4、SUVmax＞12.05和SUVmean＞10.25分别为18F-FDG PET/CT显像诊断PCNSL的最佳阈值。SUVmax＞12.05时，18F-FDG PET/CT显像对PCNSL的诊断灵敏度为83.1%，特异性为66.7%。SUVmean＞10.25时，18F-FDG PET/CT显像对PCNSL的诊断灵敏度为81.0%，特异性为77.2%。结论：1、PCNSL18F-FDG PET/CT显像具有特殊影像特征，可作为诊断PCNSL的重要参考依据。2、PCNSL中SUVmax和SUVmean明显高于脑胶质瘤及脑转移瘤。3、SUVmax＞12.05和SUVmean＞10.25分别为18F-FDG PET/CT显像诊断PCNSL的最佳阈值，在此阈值下诊断PCNSL具有较高的敏感性、特异性。4、在诊断PCNSL方面SUVmean比SUVmax特异性高，SUVmax比SUVmean敏感性高。更多还原

【Abstract】 Objective：In this study, all diagnostic reference of18F-FDG PET/CT indifferential diagnosis PCNSL, were been statistically analyzed．The study alsoproved good clinical value of differential diagnosis PCNSL using18F-FDGPET/CT.Finally, it can provide scientific and standard diagnostic criterion fordiagnosis PCNSL and improve the accuracy of18F-FDG PET/CT in diagnosingPCNSL．Methods：1. All Cases came from our hospital.40patients those who have had18F-FDGPET/CT examination in our hospital were studied.Including10cases of PCNSLpatients,18cases of gliomas patients and12cases of patients with brain metastases,a total of78lesions. All lesions were confirmed by pathology or clinical follow-up.2. Imaging instrument was German Siemens Discovery16HR PET/CT.Firstspiral CT scan, acquisition conditions: tube voltage120kV, tube current of80mA,tube lap rotation time0.4s, thickness3.75mm. PET acquisition and reconstruction:3D acquisition, take six to eight beds, each bed of chest and abdomen is2min, andeach bed of brain is5min. After the data acquisition is completed to CT attenuationcorrection of the PET image, the computer software to automatically complete theCT image and the PET image reconstruction and fusion after correction, respectivelyget CT, PET and PET/CT images.The imaging results is common interpreted by two or three experiencednuclear medicine physicians and physicians of Radiology Imaging. 3.To analyze the imaging results of78lessions according to18F-FDG PET/CTimaging, and summarize the performance characteristics of PCNSL18F-FDG PET/CT imaging.4.The maximum standardized uptake value (SUVmax)and the meanstandardized uptake value(SUVmean), were the two mainly diagnostic references of18F-FDG PET, which were analyzed in this study. The statistical distribution ofSUVmax and SUVmean of78lesions were observed.Between-group differences inSUVmax and SUVmean of PCNSL with gliomas and brain metastases wereanalyzed.With an area under the ROC curve to analysis the best cut-off value of theSUVmax and SUVmean in diagnosing PCNSL.Finally the diagnostic value of thetwo references of PET had been evaluated．5.Statistical analysis: SPSS18.0statistical software for data analysis was used.The uptake degree of radiotracer SUVmean and SUVmax in PCNSL, gliomas andbrain metastases were represented by x±s. Independent sample t test between thegroups comparing were used; The Receiver Operating characteristics(ROC) Curvewas used to evaluate the diagnostic value of SUVmax and SUVmean for PCNSL,the area under the ROC curve was used to evaluate the diagnostic value of SUVmaxand SUVmean.Results:1. PCNSL was a kind of multiple tumor and mainly occur on the screen andmore occur in the deep brain. Its uptake of18F-FDG was significantly higher and thetracer inside the lesions was evenly.Otherwise, inside the lesions hemorrhage,necrosis, cystic degeneration and calcification were rare. And peritumoral edemawas rare, mainly in mild to moderate edema.2. The SUVmax in PCNSL was higher than gliomas, there was a significantdifference between the two sets of data(t=2.996, p=0.004); The SUVmax in PCNSLwas higher than brain metastases, there was a significant difference between the twosets of data(t=4.143, p=0.000).3. The SUVmean in PCNSL was higher than gliomas, there was a significant difference between the two sets of data(t=3.505, p=0.001); The SUVmean in PCNSLwas higher than brain metastases, there was a significant difference between the twosets of data(t=4.985, p=0.000).4. SUVmax>12.05and SUVmean>10.25was the optimal threshold for18F-FDG PET/CT imaging in the diagnosis of PCNSL.When SUVmax>12.05, thesensitivity for the diagnosis of PCNSL was83.1%, the specificity was66.7%. WhenSUVmean>10.25, the sensitivity for the diagnosis of PCNSL was81.0%, thespecificity was77.2%.Conclusions:1.18F-FDG PET/CT imaging can be used as an important reference for thediagnosis of PCNSL which had special findings.2. The SUVmax and SUVmean of PCNSL was significantly higher than that ingliomas and brain metastases.3. The optimal threshold value of18F-FDG in diagnosing PCNSL wasSUVmax>12.05and SUVmean>10.25, there is a high sensitivity and specificity inPCNSL diagnosis at this threshold.4. The diagnostic specificity of SUVmean is superior to that of SUVmax; thediagnostic sensitivity of SUVmaxis superior to that of SUVmean.更多还原