Uniformity-modeled Magnetic Resonance Electrical Properties Tomography for Nasopharyngeal Carcinoma

Abstract

Based on Magnetic Resonance Imaging, Magnetic Resonance Electrical Properties Tomography is a promising means to reveal the conductivity and permittivity distributions of biological tissue, without any additional electrodes or coils. The benefit of the Magnetic Resonance Electrical Properties Tomography was that the tumor lesion could be distinguished early than the changes happened in the structure. Many studies have been done in the field of the inversion algorithms to process the radio frequency magnetic field. The radio frequency magnetic field mapping is the foundation of the Magnetic Resonance Electrical Properties Tomography. The tissue electrical properties control the behavior of magnetic field, which can be measured by MRI scanning. In the paper, the target application of the tomography is clinical nasopharyngeal carcinoma screening. With a 3 Tesla MRI scanner, the radio frequency magnetic field mapping was carried. The field of view was 239 × 209 mm2 with the longitudinal dimension of 120 mm. A Longitudinal-relaxation-time turbo-spin-echo imaging was implemented as a reference of the lesion. Base on the Helmholtz equation, which assuming the distribution of electrical properties smooth, the conductivity and permittivity images were reconstructed. The image by the longitudinal relaxation time turbo spin echo sequence presented a proof of the position of the Nasopharyngeal Carcinoma lesion. From the two resultant properties images, the anatomical structure was acceptable, but the lesion region could not be recognized due to the algorithm itself. A gradient-model algorithm is in progress to solve the problem for potential medicine applications.