甲状腺大小对比值法测量甲状腺摄锝功能的影响

目的:探讨比值法测量甲状腺摄锝功能的影响因素,以对比值法进行优化提高其测量准确性。材料与方法:选择389例研究对象行甲状腺静态显像,计算甲状腺大小、摄取比、摄锝率,并对摄取比采用不同方法校正,计算校正比1、校正比2,比较各指标与摄锝率的相关性,比较摄取比、校正比1、校正比2与摄锝率的诊断符合率。结果:①甲状腺大小与摄锝率呈正相关(r=0.663,P=0.000);②摄取比、校正比1、校正比2均与摄锝率呈正相关(r=0.900,0.974,0.984,P=0.000),校正比与摄锝率相关程度高于摄取比;③校正比1、校正比2与摄锝率的诊断符合率分别为93.3%,95.9%,明显高于摄取比与摄锝率的符合率83.3%(χ2=18.9或33.1,υ=1,P=0.000);④甲状腺缩小时,摄取比误诊率44.4%,摄锝减低时,摄取比误诊率为31.9%。结论:甲状腺大小是影响摄取比判断甲状腺摄锝功能的准确性的重要因素,摄取比以甲状腺大小校正后可以更准确地反映甲状腺摄锝功能。

Influence of Thyroid Size on the Measurement of 99Tcm-pertechnetate Thyroid Uptake

Objective：To explore the influence factors on the measurement of 99Tcm-pertechnetate thyroid uptake and optimize the uptake ratio method to improve the accuracy.Methods：Thyroid static imaging was performed on 389 subjects.The index-es,including thyroid size,uptake ratio,rectified ratio1,rectified ratio2 and percentage of 99Tcm-pertechnetate thyroid uptake（PPTU） were calculated.The correlation between every index and PPTU was calculated,and then the diagnostic coincidence rates were analyzed between uptake ratio,rectified ratio1,rectified ratio2 and PPTU respectively.Results：①It was positive correlation between thyroid size and PPTU（r = 0.663,P = 0.000）;②It was positive correlation between uptake ratio,rectified ratio1 or rectified ratio2 and PPTU（r = 0.900,0.974,0.984,P values all were 0.000）,and the correlation degree of rectified ra-tios was higher than uptake ratio;③The diagnostic coincidence rates between rectified ratio1 or rectified ratio2 and PPTU were 93.3%,95.9%,which were higher than that of uptake ratio（83.3%）（χ^2 = 18.9 or 33.1,υ = 1,P = 0.000）;④Misdiagnostic rate was 44.4% when the thyroid size was reduced and 31.9% for low PPTU.Conclusions：Thyroid size is an important influence factor to the accuracy of the 99Tcm-pertechnetate thyroid uptake ratio measurement.The rectified uptake ratio upon the thyroid size could reflect the 99Tcm-pertechnetate uptake function more accurately.