对MRI设备层间射频信号干扰进行检测的实践

摘要

目的 对3台MRI设备的层间射频信号干扰情况进行检测,以加深对层间射频信号干扰现象的认识.方法 通过3台MRI设备(设备1:GE 1.5T HDi,装机时间:2012年;设备2:GE 3.0T HD,装机时间:2006年;设备3:GE3.0T 750W,装机时间:2016年)采用轴位T1WI序列扫描ACR模体,记录层间距为5.0、1.0、0.5和0 mm时的SNR,绘制SNR变化百分比与层间距百分比的函数图.处置标准:当层间距从5 mm减小到0时,由层间射频信号干扰作用所导致的SNR的下降不超过20％.结果 当层间距由5 mm减小到0时,设备1的SNR下降幅度为18.16％,设备2的SNR下降幅度为23.57％,设备3的SNR下降幅度为10.75 ％;设备1和设备3的层间射频信号干扰检测结果达到处置标准,设备2(使用时间超过10年)的检测结果未达标.结论 3台MRI设备都存在不同程度的层间射频信号干扰现象,其中使用时间最久的设备检测结果不达标.层间射频信号干扰检测应该在临床质量控制工作中受到重视.%Objective To detect the cross-talk RF signal interference of three MRI scanners,in order to deepen the understanding of cross-talk RF signal interference.Methods Three different GE magnetic resonance imaging scanners (GE 1.5T HDi,installation time:2012;GE 3.0T HD,installation time:2006;GE 3.0T 750W,installation time:2016) were tested.The axial T1-weighted sequence was used to scan ACR phantom.Slice gaps with 5.0 mm,1.0 mm,0.5 mm and 0 were performed,respectively.SNR values were also recorded.Based on the results,the percentage change charts of SNR with slice gaps were made.Test standard was set as SNR decreased less than 20 ％ when the slice gap reduced from 5 mm to 0.Results When slice gap was reduced from 5 mm to 0,SNRs for three scanners decreased by 18.16 ％,23.57％ and 10.75％,respectively.Both the results of cross-talk obtained with GE 1.5T HDi and GE 3.0T 750W scanner met the test standard,while the result obtained with GE 3.0T HD (used for more than 10 years) was below the standard.Conclusion The cross-talk RF signal interference still exists for three MRI scanners.The test result of the scanner used for the longest time is unqualified.The quality control test of cross-talk should be done in the daily work.