^(18)F-FDG PET/CT显像评价胃癌肺转移

Evaluation of Lung Metastasis in Gastric Cancer by ^(18)F-FDG PET/CT Imaging

目的研究^(18)F-FDG PET/CT显像对胃癌患者肺转移诊断与鉴别诊断的临床价值。方法回顾性分析2011年9月至2015年3月间通过手术切除或胃肠镜活检病理诊断为胃癌(gastric carcinoma,GC)且在该中心进行^(18)F-FDG PET/CT显像的患者,选取91例术前怀疑肺转移的患者,其中男性72例,女性19例,中位年龄(60.6±14.2)岁(年龄范围17~86岁),统计肺转移灶的直径,勾画感兴趣区ROI并记录胃原发灶及肺部转移灶的SUVmax值。91例患者中原发灶为腺癌70例,其中管状腺癌29例、黏液腺癌6例、乳头状腺癌22例、低分化腺癌13例;原发灶为印戒细胞癌21例。所有患者在检查后都经过了6~36个月随访,随访至2015年7月,随访包括穿刺或手术活检、监测血浆CEA水平及影像学检查。结果 91例GC术前怀疑肺转移的患者中,通过病理活检或临床/影像学随访证实63例为恶性,其中2例PET/CT显示为阳性患者纤维支气管镜活检证实为原发性肺鳞癌,在61例肺转移患者中55例PET/CT显示为阳性,6例为假阴性;28例肺部良性病灶患者中,23例PET/CT显示为阴性,5例为假阳性。PET/CT对于胃癌患者肺转移的诊断敏感性、特异性、准确性、阳性预测值及阴性预测值分别为90.16%、82.14%、87.64%、91.67%和79.31%。转移病灶的平均直径为(13.21±9.15)mm,而转移病灶的SUVmax平均值为(5.53±3.78),二者相关性有统计学意义(P<0.01)。胃原发灶为腺癌SUVmax平均值为(6.25±3.67),印戒细胞癌SUVmax平均值为(3.14±3.19),两组间差异有统计学意义(P=0.006)。肺转移病灶的SUVmax平均值为(5.53±3.78),胃原发病灶的SUVmax平均值为(6.19±3.18),两组间Spearman秩相关系数为0.658,呈正相关。而肺转移病灶的SUVmax平均值低于胃原发灶,差异无统计学意义(P>0.05)。结论 18F-FDG PET/CT显像对于胃癌患者肺转移病灶的发现及良恶性判断具有很高的敏感性、特异性和准确性,病灶大小和SUVmax值正相关,病灶越大SUVmax值越高,肺转移病灶的SUVmax值和原发病灶的病理类型及SUVmax值正相关。

Objective To examine the clinical value of 18F_FDG PET/CT imaging in the diagnosis and differential diagnosis of lung metastasis in gastric cancer. Methods Clinical data of 91 patients who were diagnosed as having gastric cancer by patho- logical examination after surgery or gastroscopic biopsy and underwent 18 F-FDG- PET/CT for evaluation of lung metastasis from gastric cancer were retrospectively analyzed. The diameter,ROI and SUVmax of metastatic lung lesions and primary gastric le- sions were obtained. There were 72 men and 19 women with their middle age of （60.6± 14.2） years（range 17 to 86 years）. There were adenocarcinoma in 70 cases, canalicular adenocarcinoma in 29 cases, mucinous adenocarcinoma in 6 cases, papillary adenocarcinoma in 22 cases,poorly differentiated adenocarcinoma in 13 cases and signet-ring cell carcinoma in 21 cases. All patients were followed up after 18 F-FDG PET/CT imaging for 6 to 36 months until July 2015. The results of puncture and surgical biopsy,and radiological examination were obtained,and the changes of CEA levels monitored during the follow-up. Results A total of 63 cases were confirmed to be lung metastasis by pathological and follow-up radiological examination among the 91 pa- tients suspected of lung metastasis before the operation. Two cases, which were positive in PET/CT, were demonstrated to be primary squamous cell lung cancer by fiber bronchoscopy. Fifty-five out of the 61 cases of lung metastasis were shown positive and six negative by PET/CT. Among the 28 cases of benign lung lesions,23 were shown negative and 5 false-positive by PET/ CT. The sensitivity, specificity, accuracy, positive prediction rate and negative prediction rate of PET/CT were 90.16%, 82.14% ,87.64% ,91.67% and 79.31% ,respectively. The average diameter of metastatic lung lesions（13.21±9.15）mm was significantly associated with the SUVmax（5.53±3.78）（P〈0.01）. Significant difference was noted in the SUVmax between adenocarcinoma（6. 25±3.67）and signet ring cell cancer（3. 14±3.19）（P=0. 006）. The average SUVmax of lung metastasis le-sions（5.53 ± 3.78）was positively associated with that of primary gastric cancer （6.19 ±3.18）with the Spearman＇ r being 0. 658. There was no significant difference in the SUVmax between the lung metastasis lesions and primary gastric lesions. Conclusion 1, F-FDG PET/CT has high sensitivity, specificity and accuracy in the evaluation of lung metastasis in gastric canc- er. The SUVmax of the lung metastasis lesions is positively associated with tumor size. The larger the lesion is, the higher the SUVmax of the lung metastasis is. The latter also positively correlates with the pathological type and SUVmax of the primary gastric tumor.