一种基于静态场磁化原理的肝脏铁过载检测方法

A Detection Method of Liver Iron Overload Based on Static Field Magnetization Principle

磁感应法通过测量肝脏组织磁化率来实现无创检测肝脏铁过载。为解决涡流效应对磁化率测量干扰的问题,针对线圈系统提出一种基于静态场磁化原理的改进方法:即采用直流激励方式消除涡流效应影响,通过旋转接收线圈获得感应电压。计算了圆柱形介质由于磁化效应产生的磁场,推导了接收线圈最大感应电压相对变化量表达式。对改进的线圈系统建模仿真,得到了介质磁化率与接收线圈最大磁通量、最大感应电压和最大感应电压相对变化量的关系,并将仿真结果与理论计算结果进行对比。结果表明,仿真结果与理论计算结果能够较好吻合,该方法可以有效消除涡流效应影响。

Magnetic induction method aims at the noninvasive detection of liver iron overload by measuring the hepatic magnetic susceptibility. To solve the difficulty that eddy current effects interfere with the measurement of magnetic susceptibility, we proposed an improved coil system based on the static field magnetization principle in this study. We used a direct current excitation to eliminate the eddy current effect, and a rotary receiver coil to get the induced voltage. The magnetic field for a cylindrical object due to the magnetization effect was calculated and the relative change of maximum induced voltage was derived. The correlation between magnetic susceptibility of object and maximum magnetic flux, maximum induced voltage and relative change of maximum induced voltage of the receiver coil were obtained by simulation experiments, and the results were compared with those of the theory calculation. The contrast shows that the simulation results fit the theory results well, which proves our method can eliminate the eddy current effect effectively.