摘要
利用单通道直流高温超导磁强计(de-SQUID),在磁屏蔽室内测量心脏跳动产生的磁场信号。改变无磁床的位置得到胸前平面6×6的正方格子上各点的心磁信号,以同时记录的心电信号为时间基准,对心磁信号作平均处理。通过二维双线性插值,得到时域心磁分布图,可观察一个心动周期内的心磁分布变化。为了提高心磁信号的信噪比,我们在信号平均处理的基础上通过傅立叶滤波,消除电网干扰和高频噪声。快速傅立叶变换算法简单,效果显著。我们在此基础上观察到心动周期内心磁图QRS和T波段的反向现象。
In a magnetically shielded room, we use single-channel high Tc dc-SQUI D magnetometer to record the magnetic field perpendicular to the human chest pla ne generated by heart-beat. The raw magnetic field signals on a 6×6 grid over t he chest area were recorded in real time trace, and simultaneous ECG signals wer e registered as time reference, we then averaged the MCG data beat-to-beat and u se linear algorithm to perform a magneto cardiogram in the plane parallel to the chest. We can see the change of magneto cardiogram in one beat. In order to enh ance signal-to-noise ratio, we made use of basic Fourier transform method which has shown nice results in eliminating high frequency components mainly caused by electro circuits. Through further analysis, we observed an interesting field si gnal inversion in the QRS and T wave bands.
出处
《中国医学物理学杂志》
CSCD
2005年第2期481-483,459,共4页
Chinese Journal of Medical Physics
