^11C—MET和^18F—FDG PET／CT诊断胶质瘤术后残余或复发的比较

目的探讨^11C甲基蛋氨酸（MET）PET／CT对胶质瘤术后残余或复发病灶的诊断价值，并与^18F-FDG进行比较。方法46例胶质瘤术后患者均行^11C—MET和^18F-FDGPET／CT颅脑显像，2次显像间隔时间在5d内。采用ROI技术计算肿瘤与对侧灰质和白质比值。胶质瘤残余或复发病灶的诊断根据手术或立体定向活组织病理学检查、MRI、CT等影像学检查及临床随访，随访时间〉6个月。统计学比较采用z。检验或独立样本t检验。结果46例胶质瘤术后患者中残余或复发者36例。^11C-MET、^18F-FDGPET／CT显像对残余或复发病灶诊断的灵敏度分别为94．4％（34／36）、47．2％（17／36），χ2=19．429，P〈0．001；特异性分别为90．0％（9／10）、100％（10／10），χ2＝1．053，P〉0．05；准确性分别为93．5％（43／46）、58．7％（27／46），χ2=15．294，P〈0．001。半定量分析：^11C—MET肿瘤／灰质比值为1．68±0．23，明显高于^18F—FDG的1．13±0．51（t=5．877，P〈0．001），^11C—MET肿瘤／白质比值为2．52±0．28，明显高于^18F—FDG的1．42±0．57（t=10．470，P〈0．001）。结论^11C-METPET／CT显像对胶质瘤术后残余或复发病灶的诊断具有一定的临床价值，并优于^18F—FDGPET／CT显像。

Comparison between 11 C-methionine and 18F-FDG PET/CT in diagnosing residual or recurrent glioma

Objective To assess the value of 11 C-methionine (MET) PET/CT for the diagnosis of residual or recurrent glioma in comparison to 18 F-FDG PET/CT. Methods Forty-six patients suspected of residual or recurrent glioma underwent both 11 C-MET and 18 F-FDG PET/CT within 5-day interval. The glioma was considered as positive on PET/CT images based on ( 1 ) visual judgment of higher tracer uptake compared with the normal gray matter; (2) semiquantitative analysis of tumor to contralateral normal gray matter (T/G) and contralateral normal white matter (T/W) ratios. The diagnosis was confirmed by stereotsctic biopsy or radiological findings of MRI or CT and clinical follow-up ( ＞6 months). The Chi-square test and paired t test were used for statistical analysis. Results Residual or recurrent glioma was confirmed in 36 patients. The sensitivity, specificity, accuracy of 11C-MET and 18F-FDG PET/CT were 94.4% (34/36) vs 47.2% (17/36), 90.0% (9/10) vs 100% (10/10), 93.5% (43/46) va 58.7% (27/46) (x2 =19. 429, 1. 053, 15. 294, P ＜0.001, ＞0.05, ＜0.001 ), respectively. The T/G and T/W ratios of residual/recurrent giloma by 11 C-MET were significantly higher than those by 18 F-FDG (T/G ratio: 1.68 ± 0.23 vs 1.13 ±0.51, t = 5. 877, P ＜ 0. 001; T/W ratio: 2.52 ± 0.28 vs 1.42 ± 0. 57, t = 10. 470, P ＜0. 001 ). Conclusion 11 C-MET PET/CT is more sensitive and accurate than 18 F-FDG PET/CT for the detection of residual or recurrent glioma.