动态参考相位在低场磁共振测温中的应用研究

摘要

目的:探讨动态参考相位在低场磁共振测温中的应用,以解决相位图像中相位缠绕引起的问题,从而提高测温精度.方法:将自制体模放在水浴中加热,然后进行降温实验,每间隔1 min采集一次数据,直到温度降到36℃采集最后一组数据,将采集的数据转化为相位图像,然后采用动态参考相位方法获得相位差图像,从相位差图像上选择一个感兴趣区域(ROI),利用质子共振频率(PRF)方法实现温度的测量.结果:成功解决了相位的缠绕问题,测温精度在体线圈中可达到±1.5℃.结论:解决了由相位缠绕带来的问题,同时采用一种环形ROI区域,使得测温精度有很大提高,与传统方法对比实验表明,该方法存在明显的优越性.%Objective To explore the application of dynamic reference phase at low field MR temperature measurement to solve the problem of phase wrap and improve the precision of temperature measurement.Methods The home-made phantom was heated in water bath,and then it underwent cooling experiments.The data were collected once a minute and the last set of data was acquired when the temperature dropped to 36 C.All the data were transformed into the phase images.Dynamic reference phase method was used to obtain phase difference images.Then the region of interest(ROI) was chosen from phase difference images using proton resonance frequency method.Results The experimental results showed that the problem of the phase wrap was solved,and that the temperature measuring accuracy was limited in 1.5 ℃.Conclusion The method presented has the problem of phase wrap solved and the temperature measuring accuracy increased through a circular ROI,and thus gains advantages over the traditional measurement.