^(18)F-FDG PET/CT对偶发回盲部高代谢灶的良恶性判断价值

The discrimination of ^(18)F-FDG PET/CT detection of incidental ileocecal fluorodeoxyglucose uptake

背景与目的:18F-脱氧葡萄糖(FDG)作为最常用的PET/CT示踪剂,多用于肿瘤显像,可反映组织葡萄糖的代谢状况,然而正常人肠道亦可出现生理性的放射性摄取增高。由于回盲部是各种恶性肿瘤及炎性疾病的好发部位,故本研究探讨PET/CT偶发回盲部FDG高代谢灶摄取程度及其功能-解剖形态特征对回盲部疾病的鉴别诊断价值。方法:回顾性分析28例PET/CT意外探测到回盲部高放射性摄取灶的病例,半定量分析局部病灶放射性摄取程度,9例行手术证实病理,10例行肠镜检查,无法取得病理学证据者行6个月以上的长期随访。所有临床资料及半定量分析数据汇总后行单因素方差分析。结果:在所有回盲部FDG高代谢病灶中,14例(50.0%)生理性摄取病灶SUVmax平均值为5.2±1.6,8例(28.6%)良性疾病病灶SUVmax平均值为6.8±4.1,6例(21.4%)恶性肿瘤病灶SUVmax平均值为12.8±5.5。统计学分析提示生理性摄取组及良性疾病组间差异无统计学意义(P=0.361),而与恶性肿瘤组相比,差异有统计学意义(F=10.128,P=0.001)。ROC分析显示,当SUVmax为6.75时,回盲部恶性病灶诊断灵敏度及特异性分别为100%和86.4%。结论:18F-FDGPET/CT在回盲部病灶的良恶性鉴别诊断上有重要的价值,而在图像判读过程中要充分重视肠道生理性摄取的影响。半定量分析对于生理性摄取和回盲部的良性疾病的鉴别价值不大。

Background and purpose：As the most common tracer used for PET/CT to detect malignant tumors, 18F-fluorodeoxyglucose （18F-FDG） can reflect the metabolism of glucose. However, there exists physiologic uptake in the intestinal tract of healthy people. Because ileocecal foci is predilection site of malignant tumors and inflammatory disease, the purpose of this study was to investigate the discrimination of PET/CT detection of incidental ileocecal high FDG uptake. Methods：We retrospectively analyzed 28 unexpected ileocecal focal uptake of 18F-FDG localized by PET/CT, and then semi-quantitatively analyzed the extent of radioactive uptake in ileocecal foci. After PET/CT, the etiology of the findings was confirmed histologically by surgery, endoscopic or by long-term follow-up. All the data were assessed for statistical significance using one-way ANOVA. Results：In all the ileocecal foci, there were 14（50%） physiologic FDG uptake, 8 （28.6%） benign diseases and 6 （21.4%） malignant tumor. Maximal standardized uptake value was 5.2±1.6 in physiologic uptake, 6.8±4.1 in benign lesions and 12.8±5.5 in malignant lesions. There was statistically significant difference between malignant tumors and the other 2 groups. According to ROC analysis, when SUVmax was 6.75, the sensitivity and specificity of ileocecal malignant tumor were 100% and 86.4%, respectively. Conclusion：The significant value of discrimination between benign and malignant lesions of ileocecal focal FDG uptake by PET/CT was affirmative. It is very important to recognize physiologic uptake of ileocecal conjunction in the interpretation of image. Semi-quantitative analyze was not helpful to identify benign lesions from physiologic uptake.