基于高场3 T磁共振的人体组织电特性成像

结合现代的影像学方法，提出了一种基于磁共振成像的生物组织电特性成像方法.根据磁共振图像扫描信号中包含目标体的电导率和介电常数等信息这一原理，从法拉第定律和安培定律出发，推导出了激励射频磁场与电特性之间的关系.利用基于双角度法的自旋回波扫描序列，对志愿者头部进行了高场3 T下的磁共振成像实验，初步得到了质子密度像、射频场映像以及相应的电特性像.改进的算法中引入梯度项后，图像上不同组织内部的电特性变化更加明显.与传统电阻抗成像以及常规磁共振成像相比，本文的新型磁共振电特性成像兼具高对比度和高分辨率的特点，作为一种功能成像，有望在相关重大疾病的预防和诊断方面发挥作用. 

Study on In-vivo Electrical Properties Tomography for Human Tissue by High Field Magnetic Resonance

Early screening and diagnosis of diseases, such as malignant tumor and stroke, have always been the focus in the field of clinical medicine. Combined with modern imaging methods, a magnetic-resonance-imaging (MRI) based electrical characterization method for biological tissues was proposed. According to the fact that MRI scanning signal having the information of the electrical conductivity and dielectric constant in target body, the interaction between radio frequency magnetic field and electrical properties under the Faraday''s and Ampere''s laws was derived. Taking the volunteer''s head as the condition of the imaging experiment, a high field MRI scanner experiment was carried out based on a double-angle method with spin echo sequence to obtain the preliminary images for the radio frequency magnetic fields and the electrical properties.Results show that, when the gradient terms were involved in the improved algorithm, the electrical characterization of different tissues shown in the image was more evidence. Compared with the traditional electrical impedance tomography and conventional MRI, the new magnetic resonance electrical properties tomography presents higher contrast and higher resolution.As a kind of functional imaging, it is hopeful to be used in the prevention and diagnosis of relevant major diseases.