A Study of the Nuclear Magnetic Resonance (NMR) Relaxation Times to Characterize the Pathophysiology of Lung Injuries.

点击翻译按钮获取中文摘要

We previously found that the nuclear magnetic resonance (NMR) relaxation times T_1 and T_2 characterized various lung injuries (1). The present project investigated the pathophysiology of lung injury through the NMR relaxation behavior of water molecules in lung tissue.1. Two T_2 components (T_2 fast : T_<2f> and T_2 slow : T_<2s>) have been observed for peripheral lung tissue (1-3). We analyzed the origin of water for these components and found that the T_<2f> component related to the water in alveolar walls, mainly the intracellular water of alveolar epithelial cells, and the T_<2s> component related to the interstitium (4).2. We developed a motion insensitive NMR imaging technique which we call Interleaved Line Scan (ILS) and measured the two components of T_2 for peripheral lung tissue in living spontaneously breathing rats (5). With this technique, we demonstrated the time course of T_2 in endotoxin lung injury using living animals (6). We are now to develop a method to measure the in-vivo relaxation times of lung tissue using a surface coil.3. The changes in T_1 and T_2 of lung injuries reflect the interactions between water molecules and tissue's macromolecules (1-3). We measured the temperature dependence of T_1 and T_2 for experimental lung injuries to investigate the state of water in the tissue. The results suggest that the changes in activation energy of water molecules is different for the normal and injured lung tissues. With the calculated activation energy of water molecules, it would be possible to understand the damages of tissue macromolecules in various stages and types of lung injury.