Proposal of New Functional NMR Imaging : Development of Double-Quantum-Filtered MRI

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The Aims of this project is 1) to reach an understanding of factors governing the NMR relaxation of water in biological systems and 2) to develop new functional MR imaging based on the double-quantum-filter NMR and the chemical shift imaging to follow "order" structure of water and to use it to understand physiological processes in healthy and pathological tissues.1) Development of double-quantum-filter NMR imaging : We have introduced H-1 slice selective double-quantum-filter NMR imaging (H-1 DQF MRI) which depicted ordered water (bound water) in biological tissues selectively, and also developed H-1 and H-2 chemical shift double-quantum-filter NMR imaging (H-1 and H-2 DQF CSI) which depict water in a certain molecular environment through selective window.2) Assessment of healing process of ruptured Achilles tendon by H-1 DQF MRI : Tissues are characterized by the dependence of their DQF signal on the DQ creation time, τ. The H-1 DQF image changed dramatically during the healing process on the injured Achilles tendon for 21 weeks. These changes matched the phases of the healing process. By using a τ-weighted contrast, the DQF images indicate the part of tendon which has not completely healed, even after the conventional MRI appeared normal.3) Application of H-1 DQF MRI on in vivo system : Using a4.7T animal MR scanner, H-1 DQF MRI was applied hind limbs of anesthetized rabbits. The Achilles tendon and other tendons were well depicted as highlighted. We still continue to optimize parameters for measurement, but we have already collect enough basic data for the next step : human application.