11C-胆碱与18F-FDG双时相PET/CT显像结合高分辨率CT在孤立性肺结节鉴别诊断中的应用

目的比较11C-胆碱（11C-CHO）PET/CT、18F-FDG双时相PET/CT、常规18F-FDG PET/CT、11C-CHO+18F-FDG双时相PET/CT显像结合高分辨率CT（HRCT）4种方法对鉴别诊断孤立性肺结节（SPN）良恶性的价值。方法对28例SPN患者进行18F-FDG PET/CT显像（注药后l h显像，2 h行延迟显像）和11C-CHO PET/CT显像（于注药10 min后进行）。PET图像判断以SPN最大截面勾画ROI，计算SUV_max作为半定量指标，SUV_max ≥ 2.5为阳性，18F-FDG PET/CT延迟显像SUV_max上升10%为恶性病变（阳性），下降或升高 < 10%为良性病变（阴性）。HRCT以是否有分叶征、短细毛刺、胸膜尾征、支气管充气征、血管集束征、空泡征为分析良恶性的指征。所有病例进行临床综合分析及随访，以影像诊断是否符合临床随访及病理结果作为判断标准。组间SUV_max的比较采用t检验；计数资料的比较采用χ2检验。结果 28例SPN患者中，病理或临床随访诊断发现肺癌17例，结核7例，结节病4例。常规18F-FDG PET/CT显像确诊21例，18F-FDG双时相PET/CT显像确诊24例，11C-CHO PET/CT显像确诊23例，11C-CHO +18F-FDG双时相PET/CT+HRCT确诊27例。28例患者良恶性结节的18F-FDG及11C-CHO PET/CT的SUV_max比较，差异有统计学意义（t=10.57和13.19，均P < 0.05）。良恶性结节分叶、毛刺、胸膜尾征、血管集束征之间的差异有统计学意义（χ2=9.27、10.36、14.31和17.52，均P < 0.05）。11C-CHO+18F-FDG双时相PET/CT+HRCT联合显像的灵敏度为81.8%，特异度为94.1%，准确率为96.4%，明显高于非联合显像。结论 11C-CHO+18F-FDG双时相PET/CT+HRCT能较好地鉴别SPN的良恶性，三者联合能提高对SPN的诊断率。

Application of 11C-CHO and 18F-FDG dual-phase PET/CT imaging combined with high-resolution computed tomography in differential diagnosis of solitary pulmonary nodules

Objective To compare choline (11C-CHO) PET/CT,conventional 18F-FDG PET/CT,18F-FDG double-phase PET/CT,and 11C-CHO PET/CT +18F-FDG double-phase PET/CT imaging combined with high-resolution computed tomography(HRCT) to determine whether differential diagnosis value for solitary pulmonary nodules (SPN) is benign or malignant.Methods This study included 28 patients who were clinically diagnosed with SPN.Patients were injected with 18F-FDG then subjected to PET/CT scan after 1 and 2 h and were injected with 11C-CHO then subjected to PET/CT scan again after 10 min.PET images were analyzed by SPN maximum section ROI and SUVmax as a semi-quantitative index,wherein values higher than 2.5 are considered positive for SPN.SUVmax in routine were compared with that in delayed 18F-FDG PET/CT imaging,wherein an increase of more than 10％ indicates malignant lesions (positive),whereas a decrease or increase by less than 10％ indicates benign lesions (negative).Benign or malignant lesion were analyzed with lobulation,short spiculation and pleural tail sign,air bronchogram,vascular convergence sign,and vacuole sign in HRCT imaging.All cases were analyzed and clinically followed-up.Imaging diagnoses were compared with pathological results or clinical follow-up.SUVmax comparisons between groups were tested by t-test and the enumeration data were compared by analysis of variance.Results Twenty-eight patients were pathologically diagnosed and clinically followed-up.Seventeen patients were diagnosed with lung cancer,seven with tuberculosis,and four with sarcoidosis.Twenty patients were confirmed by routine 18F-FDG PET/CT imaging,24 by double-phase 18F-FDG PET/CT imaging,23 by routine 11C-CHO PET/CT imaging,and 27 by 11C-CHO PET/CT + 18F-FDG double-phase PET/CT + HRCT.18F-FDG and 11C-CHO SUVmax in benign or malignant nodules in 28 patients were analyzed.Differences were statistically significant(t=l0.57 and 13.19,both P＜0.05).A significant difference exists between benign and malignant nodules in the leaf,burr,pleural tail sign,and vascular bundle sign(x2=9.27,10.36,14.31,and 17.52,all P＜0.05).The sensitivity,specificity and accuracy of 11C-CHO +18F-FDG dual phase PET/CT +HRCT were 90.0％,91.7％ and 96.4％,significantly higher than that of the others uncombined imaging.Conclusion 11C-CHO PET/CT + 18F-FDG dual-phase PET/CT+HRCT can determine whether SPN is benign or malignant.Combine the three scan models will improve diagnostic efficiency of SPN.