医用磁共振成像系统质量控制图像均匀度检测方法的研究

Research on Determination of Image Uniformity in Diagnostic Magnetic Resonance Imaging

目的比较分析均匀分布法与窗宽窗位法两种MRI质量控制图像均匀度检测方法的差异与关系。方法利用Magphan SMR170性能测试体模于6台MRI设备,在短时间内分别采用均匀分布法和窗宽窗位法对测试层面前后各行2次图像均匀度检测。采用统计学方法评价两种检测方法测量的一致性;采用变异系数评价两种检测方法测量重复性。结果两种检测方法测量结果采用配对t检验,差异无统计学意义(P>0.05),测量一致性良好。均匀分布法测量结果的变异系数均大于0.16%,窗宽窗位法测量结果的变异系数除设备3之外,均小于0.09%;窗宽窗位法测量结果的变异系数均小于均匀分布法,即窗宽窗位法的测量重复性优于均匀分布法。结论相较于均匀分布法,窗宽窗位法因具有较高的检测准确度、对相关性能初始问题具备较高敏感性以及检测程序快速便捷等优势,更适用于图像均匀度的检测。

Objective To compare and analyze the difference and relationship between the uniform distributed method and the WW-WL method for MRI quality control image uniformity detection.Methods The Magphan SMR170 phantom was used to test the performance of six MRI devices.Within a short time,Uniform-distributed method and WW-WL method were used to detect the image uniformity of the front and rear lines of the test layer twice.Statistical methods were used to evaluate the consistency of the two methods.The coefficient of variation was used to evaluate the repeatability of the two methods.Results The measurement results of the two detection methods were tested by paired t-test,and P>0.05 was obtained.The difference was not statistically significant,and the measurement consistency was good.The coefficient of variation of the measured results by Uniform-distributed method was all greater than 0.16%,and the coefficient of variation of the measured results by WW-WL method was all less than 0.09%except for equipment 3.The variation coefficient of the measurement results by the WW-WL method was lower than that of the Uniform-distributed method,that is,the repeatability of the WW-WL method was better than that of the Uniform-distributed method.Conclusion Compared with the Uniform-distributed method,the WW-WL method is more suitable for the detection of image uniformity due to its advantages such as higher detection accuracy,higher sensitivity to the initial problems of related performance,quick and convenient detection procedures.