18F-FDG与11C-MET PET-CT显像对磁共振成像中环形强化脑肿瘤和非肿瘤性病变的鉴别诊断

摘要

Objective To evaluate the value of 18F-FDG and 11C-MET PET-CT scan in differentiation of brain ringiike-enhanced lesions on MRI imaging. Methods Forty-one brain ringlike-enhanced lesions on MRI imaging including 30 brain tumors and 11 non-neoplastic lesions confirmed pathologically or clinically underwent 18F-FDG and 11C-MET PET-CT brain scan. Among them, 15 patients who were suspected to have brain metastasis received body scan by 18F-FDG PET-CT. Both images were analyzed visually and semi-quantitatively. Results Visual analysis: for brain tumors the diagnostic sensitivity, specificity and accuracy of 18F-FDG PET-CT was 53.3%, 72.7%, 58.5%, versus 96.7%, 90.9%, 95.1% of 11C-MET PET-CT, respectively. All the primary foci in 9 patients with brain metastases were detected by body 18F-FDG PET-CT scan. Semiquantitative analysis: There was a significant difference in the uptake between highly differentiated malignant and poorly differentiated tumors as well as non-neoplastic lesions for both tracers (P<0.01), while between low-grade malignant tumors and non-neoplasm lesions, there was a difference in uptake only by 11C-MET (P<0.01). No significant difference between the uptakes in brain metastasis and glioblastomas was found by both tracers (P>0.05). Conclusion Both 18F-FDG and 11C-MET PET-CT are useful in differentiation of brain ringlike-enhanced lesions on MRI imaging. 11C-MET PET-CT is more helpful than 18F-FDG PET-CT in differential diagnosis of low-grade neoplastic from non-neoplastic lesions. Combination of 18F-FDG and 11C-MET PET-CT scans can improve the accuracy of differential diagnosis for brain ringlike-enhanced lesions on MRI imaging.%目的 探讨18F-FDG与11C-MET PET-CT显像对常规磁共振成像(MRI)不易鉴别的环形强化脑肿瘤与非肿瘤性病变的鉴别诊断价值.方法 对41例病史及临床体征不典型、MRI上呈相似明显环形强化的脑内病变患者,分别行18F-FDG及11C-MET PET-CT头部扫描,其中15例不除外脑转移瘤者加行18F-FDG PET-CT体部扫描,并对扫描结果进行视觉分析和半定量分析.经病理或临床证实为肿瘤性病变30例,非肿瘤性病变11例.结果 视觉分析结果显示,18F-FDG PET-CT正确诊断肿瘤性病变16例,假阴件14例,假阳性3例,诊断的敏感度、特异度和准确度分别为53.3%、72.7%和58.5%.9例脑转移瘤均通过体部扫描准确发现了肿瘤原发灶.11C-MET PET-CT正确诊断肿瘤性病变29例,假阴性和假阳件各1例,诊断的敏感度、特异度和准确度分别为96.7%、90.9%和95.1%.半定量分析结果显示,高度恶性脑肿瘤的L/WMFDC和L/WMMET均明显高于低度恶性脑肿瘤和非肿瘤性病变(均P<0.01),低度恶性脑肿瘤与非肿瘤性病变间仅L/WMMET的差异有统计学意义(P<0.01),转移瘤和胶质母细胞瘤间L/WMFDG和L/WMMET盯的差异均无统计学意义(均P>0.05).结论 18F-FDG和11C-MET PET-CT在鉴别MRI环形强化脑肿瘤中均有一定的价值,11C-MET PET-CT更有助于低度恶性肿瘤与非肿瘤性病变的鉴别,而18F-FDG PET-CT体部扫描有助于脑转移瘤的诊断;两种显像剂联合使用能提高对环形强化脑肿瘤诊断的准确度.