Fukuchi K, Uehara T, Morozumi T, Tsujimura E, Hasegawa S, Yutani K, Kusuoka H, Nishimura T
Division of Tracer Kinetics, Osaka University Medical School, Japan.
J Nucl Med. 1997 Jul;38(7):1067-73.
This study was performed to clarify the validity of quantification of myocardial wall thickening by the count increase method using electrocardiography (ECG)-gated SPECT.
We performed a phantom study to examine the quantification of this method and to clarify the relationship between the changes of relative counts and objective size (such as myocardial wall) under various conditions. In addition, in volunteers, the percent count increase (%CI) was analyzed in left ventricular segments based on circumferential profile curve analysis by ECG-gated SPECT with 99mTc-MIBI (methoxyisobutyl-isonitrile), and it was compared with the regional systolic wall thickness (%Th) assessed by echocardiography during low-dose dobutamine infusion.
In our phantom study, the relative count changes were correlated linearly with the object size only within less than 20 mm. Recovery coefficient curves were influenced by acquisition parameters such as type of collimator, diameter of camera rotation, counts and photon scattering. In ECG-gated SPECT, the %CI value was increased gradually at each stage after dobutamine infusion, in relation to the increase of the %Th seen on echocardiography, although there are significant large deviations between these two parameters.
In this study, quantitative analysis based on the %CI in ECG-gated SPECT may underestimate regional wall thickening. These data should be considered in the evaluation of the %CI as an index of myocardial function.
本研究旨在通过使用心电图（ECG）门控单光子发射计算机断层扫描（SPECT）的计数增加法来阐明心肌壁增厚定量的有效性。
我们进行了一项体模研究，以检验该方法的定量分析，并阐明在各种条件下相对计数变化与客观尺寸（如心肌壁）之间的关系。此外，在志愿者中，基于99mTc-甲氧基异丁基异腈（MIBI）的ECG门控SPECT通过圆周轮廓曲线分析，对左心室节段的计数增加百分比（%CI）进行分析，并将其与低剂量多巴酚丁胺输注期间超声心动图评估的局部收缩期室壁厚度（%Th）进行比较。
在我们的体模研究中，相对计数变化仅在小于20mm的范围内与物体大小呈线性相关。恢复系数曲线受采集参数影响，如准直器类型、相机旋转直径、计数和光子散射。在ECG门控SPECT中，多巴酚丁胺输注后各阶段的%CI值逐渐增加，与超声心动图上%Th的增加相关，尽管这两个参数之间存在显著的较大偏差。
在本研究中，基于ECG门控SPECT中%CI的定量分析可能低估局部室壁增厚。在将%CI作为心肌功能指标进行评估时应考虑这些数据。
