运动位移对SPECT心肌灌注显像结果的影响

摘要

Objective It is well known that patient motion may cause artifacts in myocardial SPECT images and affect clinical diagnosis.The aim of the study was to evaluate the effects of motion on qualitv and semi-quantitative results of myocardial perfusion images.Methods Six healthy volunteers underwent myocardial perfusion SPECT.The raw data in each case was manually shifted 1～6 frames and 1～4 pixels,respectively by using the motion correction software.The shifted raw data were then reconstructed.A semi-quantitative software was used to assess the myocardial perfusion of left ventricle.The qualitv and semi-quantitative results of the tomographic images reconstructed from the raw data with and without motion were compared and analyzed.SPSS 12.0 was used for data analysis.Results There was no visible artifact and semi-quantitative difference on the data with 1 frame and(or)1 pixel shift when compared with the original data without shift.The image artifacts became significantly deteriorated when the number of frame and (or)pixel shift was increased.In general,the image artifact of inferior and posterior wall Was related to the upward shift,and that of anterior and infero-posterior wall was related to the downward shift,that of septal. anterior, infero-posterior wall and apex was related to right-ward shift.and the septal and infero-posterior wall was related to the left-ward shift.The differences along the x-axis shift were more prominent than that of the y-axis(t=2.848.P＜0.01),and the differences in the downward and rightward shift were more severe than the upward and leftward shift(t=2.941,6.598;all P＜0.01),respectively.Conclusions Image artifacts became significant when there was motion induced by manual shift of more than one frame and(or) one pixel.Different motion directions were closely related to different segments of left ventricle.%目的 探讨运动位移对SPECT心肌灌注显像结果的影响.方法 收集健康体格检查者201 Tl心肌灌注显像资料6例,利用计算机软件对原始图像进行多组模拟位移.重建各种位移和无位移状态下的心肌断层图像,利用定量计算软件自动获得各种位移状态和无位移状态下左心室各壁段的血流灌注分数.比较各种位移状态和无位移状态下的图像及其血流灌注分数的差异.分析不同位移状态对心肌灌注显像图像质量及定量计算结果的影响.采用SPSS 12.0软件进行数据处理.结果 在各种位移方式中,1帧和1个像素的所有位移对图像质量及定量计算结果无明显影响,随着位移帧数和(或)位移距离(像素数)的增加,图像逐渐出现放射性稀疏、缺损以及变形,并出现"拖尾"、"伴影"等伪影特征.向上移动时,主要影响左心室下后壁;向下移动时,主要影响前壁及下后壁;向右移动时,主要影响间壁、心尖部、前壁及下后壁;向左移动时,主要影响问壁及下后壁.其中,沿x轴移动时心肌血流灌注分数的改变大于沿y轴移动时(t=2.848,P＜0.01),向下移动的改变大于向上移动(t=2.941,P＜0.01),向右移动的改变大于向左移动(t=6.598,P＜0.01).结论 大于1帧和1个像素的位移可对心肌灌注显像图质量及定量计算结果产生不同程度的影响,不同方向及不同幅度的位移对左心室各壁段的影响具有不同特征.