注射后不同时间SPECT显像估测甲状腺体积的变异性分析

Analysis of the variability in calculating thyroid volume by SPECT imaging at different time postin- jection

目的探讨注射Na^99Tc^mO4后不同时间SPECT显像估测甲状腺体积的差异。方法应用简单随机抽样法选取40例格雷夫斯甲状腺功能亢进症（简称甲亢）患者进行前瞻性研究。经肘静脉注射Na^99Tc^mO4后，于不同时间（5、10、15、20、25、30、45和60min）进行SPECT平面和断层甲状腺显像，采用平面法和断层积分法分别估测甲状腺体积。采用单因素方差分析、配对t检验和直线相关分析行统计学处理。结果注射后不同时间（5、10、15、25、30、45和60min）显像与20min显像比较：平面法估测甲状腺体积的相关系数为0．717～0．819（均P〈0．05），CV为（18．38±5．31）％；断层积分法估测甲状腺体积的相关系数为0．913～0．961（均P〈0．05），CV为（8．05±3．19）％。2种甲状腺体积估测方法的相关系数和CV差异皆有统计学意义（t=-13．59和-11．29，均P〈0．05）。结论注射后不同时间SPECT甲状腺显像，断层积分法估测甲状腺体积具有更好的相关性和重复性。

Objective To evaluate the variability of calculating thyroid volume by SPECT imaging at different time postinjection. Methods A total of 40 patients with Graves disease were enrolled in this prospective study using simple random sampling method. After intravenous injection of Na99TcmO4, all patients underwent planar and tomographic scintigraphy at different time points （5, 10, 15, 20, 25, 30, 45 and 60 min）, and the planar or tomographic integral method were used to estimate thyroid volume. Data were analyzed by one-way analysis of variance, paired t test or linear correlation analysis. Results For thyroid volume estimated by planar imaging, the correlation coefficients between the different time points and 20 min were 0. 717-0. 819 （all P〈0.05）, and the CV was （18.38±5.31）%. For thyroid volume estimated by tomographic integral method, the correlation coefficients were 0. 913 - 0. 961 （ all P〈 0. 05）, and the CV was （ 8.05 ± 3.19） %. Both the correlation coefficient and CV were statistically significant between the two methods （t= -13.59, -11.29, both P〈0.05）. Conclusions Tomographic integral method has better correlation and reproducibility in calculating thyroid volume compared with planar method.