Inaccuracy of Thyroid to Background Uptake Ratio in Evaluating Technetium-99m-pertechnetate Thyroid Uptake and Establishing an Improved Algorithm

Document Type : Original Article


1 Department of Nuclear Medicine, Zhongnan Hospital of Wuhan University, Hubei, China

2 Department of Applied Mathematics, School of Mathematics and Statistics of Wuhan University, Hubei, China


Objective(s): The aim of this study was to explore the accuracy of thyroid to background uptake ratio (UR) in the evaluation of 99mTc-pertechnetate thyroid uptake (TcTU) and establishment of an improved algorithm.
Methods: This study was conducted on the thyroid images of 322 patients with thyroid diseases and 67 controls. For the purpose of the study, URs of the images were calculated, and then corrected by standardized thyroid area size to establish a corrected uptake ratio (CUR). Subsequently, the accuracy between UR and CUR was compared.
Results: The results of linear regression using weighted least squares (using TcTU as a dependent variable and CUR, UR, or thyroid area size as independent variables) showed that CUR (t=105.5, P=0.000), UR (t=31.9, P=0.000), and thyroid area size (t=15.9, P=0.000) are influential factors of TcTU. Furthermore, the standardized coefficient of CUR (β=0.983) was obviously higher than those of UR (β=0.851) and thyroid area size (β=0.629). The linear goodness-of-fit between CUR and TcTU (R=0.983) was better than that between UR and TcTU (R=0.851). In addition, the total concordance rate between CUR and TcTU (96.7%) was significantly higher than that between UR and TcTU (83.0%; χ2=42.9, P=0.000). Discordance rates of CUR in large thyroid area (1.4% vs. 13.4%, χ2=17.0, P=0.000) and small thyroid area (3.3% vs. 42.2 %, χ2=44.3, P=0.000), were significantly lower than that of UR. In the abnormal thyroid areas, the discordance rates of UR obviously increased as compared to those of CUR. The UR overestimated the thyroid uptake in small thyroid areas and underestimated it in large thyroid areas.
Conclusion: Based on the findings, CUR is more accurate than UR in measuring 99mTcO4ˉ thyroid uptake; accordingly, it is more significant in the diagnosis of thyroid disease.


Main Subjects

1. Kasagi K, Hidaka A, Misaki T, Miyamoto S, Takeuchi R, Sakahara H, et al. Scintigraphic findings of the thyroid in euthyroid ophthalmic Graves’ disease. J Nucl Med. 1994; 35(5):811-817.
2. Sekulić V, Rajić M, Vlajković M, Ilić S, Bogićević M, Antić S, et al. Thyroid blood flow and uptake of technetium-99m pertechnetate in Graves’ disease. Hell J Nucl Med. 2006; 9(3):173-176.
3. Kidokoro-Kunii Y, Emoto N, Cho K, Oikawa S. Analysis of the factors associated with Tc-99m pertechnetate uptake in thyrotoxicosis and Graves’ disease. J Nihon Med Sch. 2006; 73(1):10-17.
4. Sahlmann CO, Siefker U, Lehmann K, Harms E, Conrad M, Meller J. Quantitative thyroid scintigraphy for the differentiation of Graves’ disease and hyperthyroid autoimmune thyroiditis. Nuklearmedizin. 2004; 43(4):124-128.
5. Meller J, Wisheu S, Munzel U, Behe M, Gratz S, Becker W. Radioiodine therapy for Plummer’s disease based on the thyroid uptake of technetium-99m pertechnetate. Eur J Nucl Med. 2000; 27(9):1286-1291.
6. Reinhardt MJ, Joe A, von Mallek D, Zimmerlin M, Manka-Waluch A, Palmedo H, et al. Dose selectionfor radioiodine therapy of borderline hyperthyroid patients with multifocal and disseminated autonomy on the basis of 99mTc-pertechnetate thyroid uptake. Eur J Nucl Med Mol Imaging. 2002; 29(4):480-485.
7. Reinhardt MJ, Biermann K, Wissmeyer M, Juengling FD, Brockmann H, von Mallek D, et al. Dose selection for radioiodine therapy of borderline hyperthyroid patients according to thyroid uptake of 99mTc-pertechnetate: applicability to unifocal thyroid autonomy? Eur J Nucl Med Mol Imaging. 2006; 33(5):608-612.
8. Schneider PB. Simple, rapid thyroid function testing with 99mTc-pertechnetate thyroid uptake ratio and neck/thigh ratio. AJR Am J Roentgenol. 1979; 132(2):249-253.
9. Selby JB, Buse MG, Gooneratne NS, Moore DO. The Anger camera and the pertechnetate ion in the routine evaluation of thyroid uptake and imaging. Clin Nucl Med. 1979; 4(6):233-237.
10. Gao YJ, Han JH, Xie J, Yan XH, Wang JB, Zhu XM, et al. Clinical application of quantitative 99Tcm-pertechnetate thyroid imaging (Chinese). Chin J Nucl Med. 2002; 22(4):201-203.
11. Sostre S, Parikh S. A visual index of thyroid function. Clin Nucl Med. 1979; 4(2):59-63.
12. She LQ, Mo YB, Zou DH. Predictive value of the visual index of thyroid uptake (VITU) for hyperthyroidism after 131I therapy (Chinese). J Chin Clin Med Imaging. 2000; 11(4):241-243.
13. Wallack S, Metcalf M, Skidmore A, Lamb CR. Calculation and usage of the thyroid to background ratio on the pertechnetate thyroid scan. Vet Radiol Ultrasound. 2010; 51(5):554-560.
14. Davies S, Barber D, Crisman M, Tan R, Larson M, Daniel G. Quantitative pertechnetate thyroid scintigraphy and the ultrasonographic appearance of the thyroid gland in clinically normal horses. Vet Radiol Ultrasound. 2010; 51(6):674-680.
15. He GR, Ouyang W, Liu JH, Liu WY. Effects of iodine-containing food on 99mTc and 131I uptake in patients with Graves’ disease (Chinese). J First Mil Med Univ. 2004; 24(11):1292-1294.
16. Zhang YJ, Shao P, Wang JL, Jiang CY, Chu SL. Rapid diagnosis of hyperthyroidism with 30min 99mTc pertechnetate thyroid uptake ratio (Chinese). Nucl Tech. 1994; 17(11):672-676.
17. Baskin HJ, Cobin RH, Duick DS, Gharib H, Guttler RB, Kaplan MM, et al. American association of clinical endocrinologists medical guidelines for clinical practice for the evaluation and treatment of hyperthyroidism and hypothyroidism. Endocr Pract. 2002; 8(6):457-469.
18. Gharib H, Papini E, Garber JR, Duick DS, Harrell RM, Hegedüs L, et al. American association of clinical endocrinologists, American college of endocrinology, and associazione medici endocrinologi medical guidelines for clinical practice for the diagnosis and management of thyroid nodules - 2016 update. Endocr Pract. 2016; 22(5):622-639.
19. Javadi H, Neshandarasli I, Mogharrabi M, Jalallat S, Nabipour I, Assadi M. The effect of an iodine restricted including no sea foods diet, on technetium-99m thyroid scintigraphy: a neglected issue in nuclear medicine practice. Hell J Nucl Med. 2012; 15(1):40-42.
20. Meller J, Becker W. The continuing importance of thyroid scintigraphy in the era of high-resolution ultrasound. Eur J Nucl Med Mol Imaging. 2002; 29(Suppl 2): S425-438.
21. Prakash R. Prediction of remission in Graves’ disease treated with long-term carbimazole therapy: evaluation of technetium-99m thyroid uptake and TSH concentrations as prognostic indicators. Eur J Nucl Med. 1996; 23(2):118-122.
22. Shigemasa C, Teshima S, Taniguchi S, Ueta Y, Mitani Y, Yoshida A. Pertechnetate thyroid uptake is not always suppressed in patients with subacute thyroiditis. Clin Nucl Med. 1997; 22(2):109-114.
23. Ramos CD, Zantut Wittmann DE, Etchebehere EC, Tambascia MA, Silva CA, Camargo EE. Thyroid uptake and scintigraphy using 99mTc pertechnetate: standardization in normal individuals. Sao Paulo Med J. 2002; 120(2):45-48.
24. Zantut-Wittmann DE, Ramos CD, Santos AO, Lima MM, Panzan AD, Facuri FV, et al. High pre-therapy [99mTc] pertechnetate thyroid uptake, thyroid size and thyrostatic drugs: predictive factors of failure in [131I] iodide therapy in Graves’ disease. Nucl Med Commun. 2005; 26(11):957-963.
25. Kusić Z, Becker DV, Saenger EL, Paras P, Gartside P, Wessler T, et al. Comparison of technetium-99m and iodine-123 imaging of thyroid nodules: correlation with pathologic findings. J Nucl Med. 1990; 31(4): 393-399.
26. Hou H, Hu S, Fan R, Sun W, Zhang X, Tian M. Prognostic value of 99mTc-pertechnetate thyroid scintigraphy in radioiodine therapy in a cohort of Chinese Graves’ disease patients: a pilot clinical study. Biomed Res Int. 2015; 2015:974689.
27. Espinoza PG, Guendelman CL, Quevedo Limón LN, Fernández RJ. A comparison between two imaging techniques for the diagnosis of subacute thyroiditis (de Quervain thyroiditis): brief communication. Clin Nucl Med. 2010; 35(11):862-864.