18^F-FDG PET／CT全身显像对甲状腺偶发瘤的临床意义

目的研究18^F-脱氧葡萄糖（FDG）PET／CT显像对甲状腺偶发瘤的检出率及检出恶性病灶的比例、最大标准摄取值（SUVmax）对鉴别诊断良、恶性病变的价值。方法回顾性分析2007年6月-2008年1月1190例无甲状腺癌病史的PET／CT受检者资料，对PET／CT发现的甲状腺偶发瘤行定性、半定量分析。对数据行Kruskal—Wallis检验或Spearman相关分析。结果18^F-FDG PET／CT全身显像对甲状腺偶发瘤的检出率为2．1％（25／1190），其中20例取得病理结果，良性病变9例，恶性病变11例（9例乳头状癌、1例滤泡状癌、1例肺癌转移），恶性比例高达55％（11／20）。良、恶性病变组间SUVmax差异有统计学意义（分别为4．1±1．9和13．3±11．8,Х^2=8．8，P〈0．01）。甲状腺偶发瘤最大径（1．0～4．2cm）与其18^F-FDG摄取（SUVmax为3．0—46．0）之间无相关性（r=0．25，P〉0．01）。结论18^F-FDG PET／CT检查发现甲状腺偶发瘤中甲状腺癌比例很高，其SUVmax对鉴别诊断良、恶性病变有参考价值。

Clinical significance of 18F-fluorodeoxyglucose PET/CT whole body imaging in detecting thyroid incidentaloma

Objective 18F-fluorodeoxyglucose(FDG)PET/CT is a noninvasive whole-body ima-ging technique used to evaluate various types of malignancies.Recent advances have rapidly developed it in-to a diagnostic imaging modality in ontology.The aims of this study were two.One was to estimate the de-tection rate of thyroid incidentaloma and the risk of thyroid malignancy by 18F-FDG PET/CT scan and the other Was to further understand whether the maximum standardized uptake value(SUVmax)would be helpful in differentiating benign from malignant thyroid tumor.Methods From June 2007 to January 2008,a total of 1190 subjects who had no previous history of thyroid cancer and had 18F-FDG PET/CT scan were includ-ed.All had visual interpretation and semiquantitative analyses by SUVmax at thyroid incidentalomas detected by FDG PET/CT.Kruskal-Wallis test and Spearman relation analysis were used.Results The prevalence of thyroid incidentaloma on 18F-FDG PET/CT wag 2.1%(25/1190).Of these 25 tumors,20 had histologi-cally proven.Of these 20 tumors,9 were benign and 11 were malignant(papillary carcinoma of thyroid gland in 9,follicular carcinoma of thyroid gland in I,metastatic squamous cell carcinoma from lung cancer in 1).Therefore,the cancer risk of thyroid incidentaloma was 55%(11/20).Significantly higher SUVmax in malignant than in benign nodules were observed(Kruskal-Wallis test,X2=8.8,P0.01).Conclusion Thyroid incidentaloma detected by 18F-FDG PET/CT has higher risk rate for thyroid malignancy.