Hasanov Karshi F, Ma Angela W, Nachman Adrian I, Joy Michael L G
Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON, M5S 3G8 Canada.
IEEE Trans Med Imaging. 2008 Sep;27(9):1301-9. doi: 10.1109/TMI.2008.922691.
Current density impedance imaging (CDII) is a new impedance imaging technique that can noninvasively measure the conductivity distribution inside a medium. It utilizes current density vector measurements which can be made using a magnetic resonance imager (MRI) (Scott , 1991). CDII is based on a simple mathematical expression for inverted Delta sigma / sigma = inverted Delta ln sigma, the gradient of the logarithm of the conductivity sigma, at each point in a region where two current density vectors J1 and J2 have been measured and J1 x J2 not equal 0. From the calculated inverted Delta ln sigma and a priori knowledge of the conductivity at the boundary, the logarithm of the conductivity ln sigma is integrated by two different methods to produce an image of the conductivity sigma in the region of interest. The CDII technique was tested on three different conductivity phantoms. Much emphasis has been placed on the experimental validation of CDII results against direct bench measurements by commercial LCR meters before and after CDII was performed.
电流密度阻抗成像（CDII）是一种新的阻抗成像技术，它可以无创地测量介质内部的电导率分布。它利用电流密度矢量测量，这可以通过磁共振成像仪（MRI）来进行（斯科特，1991年）。CDII基于一个简单的数学表达式：对于反Δσ/σ = 反Δlnσ，即电导率σ的对数梯度，在已测量两个电流密度矢量J1和J2且J1×J2不等于0的区域中的每个点处。根据计算出的反Δlnσ以及边界处电导率的先验知识，通过两种不同方法对电导率lnσ进行积分，以生成感兴趣区域内电导率σ的图像。CDII技术在三种不同的电导率模型上进行了测试。在进行CDII前后，人们非常重视将CDII结果与商用LCR仪表的直接台式测量结果进行实验验证。
