MRI中髋关节股头软骨的厚度测量方法

Thickness Measurement of Femoral Cartilage on Hip Joint in MRI

为了实现对核磁共振成像中髋关节软骨厚度的自动检测,该文提出了基于结合高斯滤波的零交叉点的自动测量方法。模拟人体髋关节股头软骨的厚度分布,建立二维薄面体的数学模型。引入了模拟MR图像摄影过程的点扩散函数模型,可以模拟出沿薄面体法线方向MR仿真信号的强度波形。利用基于高斯二阶微分的零交叉法可以实现对薄面体厚度的准确测量,定义薄面体的厚度为沿着薄面体法线方向的高斯二阶微分的两个零交叉点之间的距离。薄面体模型仿真和实物标本实验均验证了该方法的有效性。

A novel method, which is based on the zero-crossing points combined with Gaussian filter, is developed to estimate the cartilage thickness of hip joint automatically in magnetic resonance imaging （MRI）. A 2D mathematical model for simulating human hip joint femoral cartilage distribution is founded. Based on the model, a point spread function （PSF） is applied to simulate the MR imaging process, and then the one-dimensional profile of MR intensity values along the normal direction of the sheet structure can be performed. The simulation experiment demonstrates that the thickness of sheet structure can be accurately measured by using the zero-crossing method, where the thickness of sheet structure is defined as the distance between zero-crossing points of the Gaussian second derivatives along the normal direction. Plastic sheet simulation and the vivo experiment verify the validity of the method.