Real-Time Holographic Reconstruction of NMR Images Using a Liquid Crystal--Spatial Light Modulator

摘要

This paper notes that the description of the NMR signal obtained by NMR imaging is of the same form as the diffraction of the light or sound wave, and discusses the real-time holographic reconstruction method that recon- structs the NMR image at high speed, using the optical operation. With our holographic reconstruction method, not only can two-dimensional images can be reconstructed in a very short time, but also there is a possibility that three-di- mensional images can be reconstructed in real time. In this study, the phase-scrambling Fourier transform method is used, which requires less dynamic range for the NMR signal acquisition system. The obtained NMR signal is directly transmitted to the electronically directly writable liquid crystal--spatial light modulator and displayed. Then, the NMR image is reconstructed by the coherent optical system. An experiment of imaging and image reconstruc- tion by low-magnetic-field MRI and an experiment using the NMR signal derived from the human image obtained from the general-purpose MRI are performed and it is verified that a satisfactory image can be reconstructed from the liquid crystal--spatial light modulator with a small num - ber of pixels. A simulation experiment for the real-time reconstruction is also Performed in order to examine the usefulness of the proposed method, where NMR signal for a cross section is transmitted and displayed at a 100-ms interval, which is almost the same imaging intervals in ultrahigh-speed imaging. It is then verified that the NMR image can be reconstructed as the dynamic image.