Pathak Kumar Alok, Klonisch Thomas, Nason Richard W, Leslie William D
Division of Surgical Oncology, Cancer Care Manitoba, University of Manitoba, ON2048, 675 McDermot Avenue, Winnipeg, R3E 0V9, Canada.
Department of Human Anatomy and Cell Science, University of Manitoba, Winnipeg, Canada.
Ann Nucl Med. 2016 Aug;30(7):506-9. doi: 10.1007/s12149-016-1087-6. Epub 2016 May 25.
Follicular (FN) and Hürthle cell neoplasms (HCN) are considered indeterminate on thyroid fine needle aspiration cytology and are preoperative diagnostic challenges. The role of [(18)F]-2-fluoro-2-deoxy-D-glucose (FDG) in characterizing indeterminate thyroid nodules remains equivocal, because of the increased FDG uptake by some benign thyroid nodules. The objective of this study was to compare the FDG positron emission tomography/computerized tomography (PET/CT) characteristics of follicular (FA) and Hürthle cell adenomas (HCA).
Twenty-nine patients with 31 thyroid nodules underwent FDG-PET/CT scans of the neck and superior mediastinum for indeterminate FN/HCN, and were later found to have benign adenomas on final histopathology. All scans were reported by a single observer, who was blinded to the surgical and pathology findings. Receiver operating characteristic (ROC) curve analysis of maximum standardized uptake value (SUVmax) and the area under the curve (AUROC) were used to assess discrimination between FA and HCA. Youden index was used to identify the optimal cut-off SUVmax. Sensitivity, specificity, predictive values and overall accuracy were used as measures of performance.
The mean age of our study cohort was 60.7 ± 12.6 years and 77 % of the patients were females. Age of the patients (p = 0.48), their gender (p = 0.52), and the size of thyroid nodules (p = 0.79) were similar for FA and HCA. Increased focal FDG uptake was observed in 100 % of HCA and 52 % of FA (p = 0.02). SUVmax of HCA was significantly higher (p < 0.001) than that of FA. SUVmax of 5 was the best cut-off for discrimination between HCA and FA, with AUROC of 0.90 (95 % CI, 0.79-1.00; p = 0.001). With this cut-off, FDG-PET/CT had sensitivity of identifying HCA of 88 % (95 % CI 47-99 %), specificity of 87 % (95 % CI 65-97 %), positive predictive value of 70 % (95 % CI 35-92 %), and negative predictive value of 95 % (95 % CI 74-99 %). The overall accuracy was 87 %.
HCA shows significantly higher focal FDG uptake as compared to FA and should always be considered in the differential diagnosis of FDG-PET positive thyroid nodules.
滤泡性（FN）和许特莱细胞肿瘤（HCN）在甲状腺细针穿刺细胞学检查中被认为是不明确的，是术前诊断的挑战。[（18）F]-2-氟-2-脱氧-D-葡萄糖（FDG）在鉴别不明确的甲状腺结节中的作用仍不明确，因为一些良性甲状腺结节的FDG摄取增加。本研究的目的是比较滤泡性腺瘤（FA）和许特莱细胞腺瘤（HCA）的FDG正电子发射断层扫描/计算机断层扫描（PET/CT）特征。
29例有31个甲状腺结节的患者因不明确的FN/HCN接受了颈部和上纵隔的FDG-PET/CT扫描，最终组织病理学检查发现为良性腺瘤。所有扫描均由一名对手术和病理结果不知情的观察者报告。采用最大标准化摄取值（SUVmax）的受试者操作特征（ROC）曲线分析和曲线下面积（AUROC）来评估FA和HCA之间的鉴别能力。用尤登指数确定最佳SUVmax临界值。敏感性、特异性、预测值和总体准确性用作性能指标。
我们研究队列的平均年龄为60.7±12.6岁，77%的患者为女性。FA和HCA患者的年龄（p = 0.48）、性别（p = 0.52）和甲状腺结节大小（p = 0.79）相似。100%的HCA和52%的FA观察到局灶性FDG摄取增加（p = 0.02）。HCA的SUVmax显著高于FA（p < 0.001）。SUVmax为5是区分HCA和FA的最佳临界值，AUROC为0.90（95%CI，0.79 - 1.00；p = 0.001））。以此临界值，FDG-PET/CT识别HCA的敏感性为88%（95%CI 47 - 99%），特异性为87%（95%CI 65 - 97%）），阳性预测值为70%（95%CI 35 - 92%），阴性预测值为95%（95%CI 74 - 99%）。总体准确性为87%。
与FA相比，HCA显示出显著更高的局灶性FDG摄取，在FDG-PET阳性甲状腺结节的鉴别诊断中应始终予以考虑。
