(18)F-氟代脱氧葡萄糖正电子发射断层扫描/计算机断层扫描在甲状腺球蛋白升高且 (131)I 全身扫描阴性的分化型甲状腺癌患者中的诊断准确性：通过甲状腺球蛋白水平评估。

Diagnostic accuracy of (18)F-fluorodeoxyglucose positron emission tomography/computed tomography in differentiated thyroid cancer patients with elevated thyroglobulin and negative (131)I whole body scan: evaluation by thyroglobulin level.

机构信息

Department of Radiology, School of Medicine, The Catholic University of Korea, Seoul, South Korea.

出版信息

Ann Nucl Med. 2012 Jan;26(1):26-34. doi: 10.1007/s12149-011-0536-5. Epub 2011 Oct 5.

DOI:10.1007/s12149-011-0536-5

PMID:21971605

Abstract

BACKGROUND

To evaluate the diagnostic accuracy of (18)F-FDG PET/CT in detection of recurrent differentiated thyroid cancer (DTC) in patients with elevated stimulated thyroglobulin (Tg) or anti-Tg antibody (Ab) levels, and negative (131)I whole body scan according to the Tg level.

METHODS

PET/CT images of well DTC patients who had total thyroidectomy and radioiodine ablation were included. Patients showing elevated Tg titer (≥2.0 ng/ml after TSH stimulation) or elevated anti-Tg titer (≥70.0 IU/ml) while diagnostic radioiodine scan was negative were enrolled. PET/CT was classified as positive or negative on the basis of visual interpretation. The maximum standard uptake values (SUVmax) of the suspected lesions on PET/CT were also recorded. The PET/CT findings were compared with histological or clinical follow-up results based on other imaging modalities and serum Tg/anti-Tg Ab titers. The diagnostic performance of PET/CT was compared among 4 subgroups according to the Tg level [2 ng/ml ≤ stimulated Tg (sTg) < 5 ng/ml, 5 ng/ml ≤ sTg < 10 ng/ml, 10 ng/ml ≤ sTg < 20 ng/ml, and ≥20 ng/ml].

RESULTS

A total of 68 PET/CT images from 60 patients were included, and histological confirmations were available in 32 images. The sensitivity, specificity, accuracy, positive predictive value and negative predictive value of PET/CT were 69.4, 66.7, 69.1, 95.6, and 17.4%, respectively. There were 3 PET/CT cases with high anti-Tg Ab level, and low (<2 ng/ml) Tg level, and all 3 were positive of recurrence. The mean SUVmax of the suspected lesions on PET/CT was 2.9 ± 4.5 (range 1.3-29.7). The sensitivity of PET/CT according to Tg levels was 28.6% when Tg was between 2 and 5, 57.1% between 5 and 10, 60.0% between 10 and 20, and 85.7% when Tg was equal to or greater than 20 ng/ml sub-groups, respectively.

CONCLUSION

Diagnostic accuracy of FDG PET in radioiodine negative thyroid cancer may vary depending on serum Tg levels at imaging. (18)F-FDG PET/CT is useful in detection and localization of recurrent thyroid cancer in patients with negative diagnostic radioiodine scan despite elevated Tg greater than 20 ng/ml or high anti-Tg Ab titers. In contrast, PET/CT provides little additional information when the Tg is less than 5 ng/ml.

摘要

背景

评估（18）F-FDG PET/CT 在检测刺激后甲状腺球蛋白（Tg）水平升高或抗-Tg 抗体（Ab）水平升高且（131）I 全身扫描阴性的复发性分化型甲状腺癌（DTC）患者中的诊断准确性，根据 Tg 水平。

方法

纳入了已行全甲状腺切除术和放射性碘消融的 DTC 患者的 PET/CT 图像。招募了 Tg 滴度升高（TSH 刺激后≥2.0ng/ml）或抗-Tg 滴度升高（≥70.0IU/ml）而诊断性放射性碘扫描阴性的患者。基于视觉解释，将 PET/CT 分为阳性或阴性。还记录了 PET/CT 上可疑病变的最大标准摄取值（SUVmax）。根据其他影像学和血清 Tg/抗-Tg Ab 滴度，将 PET/CT 结果与组织学或临床随访结果进行比较。根据 Tg 水平[2ng/ml≤刺激 Tg（sTg）<5ng/ml、5ng/ml≤sTg<10ng/ml、10ng/ml≤sTg<20ng/ml 和≥20ng/ml]将 68 例患者的 68 个 PET/CT 图像分为 4 组，比较 PET/CT 的诊断性能。

结果

共纳入 60 例患者的 68 个 PET/CT 图像，其中 32 个有组织学证实。PET/CT 的灵敏度、特异性、准确性、阳性预测值和阴性预测值分别为 69.4%、66.7%、69.1%、95.6%和 17.4%。有 3 例 PET/CT 患者抗-Tg Ab 水平高，Tg 水平低（<2ng/ml），均为复发阳性。PET/CT 上可疑病变的平均 SUVmax 为 2.9±4.5（范围 1.3-29.7）。根据 Tg 水平，PET/CT 的灵敏度分别为 28.6%（Tg 为 2-5ng/ml 时）、57.1%（5-10ng/ml 时）、60.0%（10-20ng/ml 时）和 85.7%（Tg 等于或大于 20ng/ml 时）。

结论

在碘阴性甲状腺癌中，FDG PET 的诊断准确性可能取决于影像学检查时的血清 Tg 水平。（18）F-FDG PET/CT 可用于检测和定位 Tg 大于 20ng/ml 或高抗-Tg Ab 滴度升高但诊断性放射性碘扫描阴性的患者的复发性甲状腺癌。相比之下，当 Tg 小于 5ng/ml 时，PET/CT 提供的信息很少。