Analysis of Mastication Cycle on Masseter Muscle

31P磁共振波谱(31P-MRS)是唯一一种可以连续观察完整器官中磷酸肌酸(PCr)和无机磷(PI)等磷化代谢产物浓度以及细胞内pH(Phi)变化的方法。本文用31P-MRS研究了一个咀嚼周期对咀嚼肌能量代谢的影响。在确定横断面和矢状面图像视点后，对人咬肌中心进行了31P-MRS测量。在合理的S/N比值下检测MRS参数。但由于根据运动伪影考虑的S/N值较低，以及咀嚼运动过程中能量代谢的信号强度较低，这种测量是困难的。另外，还开发了利用大鼠在同一位置进行31P-MRS测量的程序，并计划将该程序应用于人类。为此，测量了咬肌的形状和重量，并制作了适用于大鼠咬肌的探头。因此，在大鼠咬肌上进行MRS测量是完全可能的，这项研究也可以推广到人类自由咀嚼的同一下颌位置上的测量。

31P Magnetic Resonance Spectroscopy (31P-MRS) is the only method whereby the concentrations of phosphorated metabolites, such as phosphocreatine (PCr) and inorganic phosphate (Pi), and the change in intracellular pH (pHi) in intact organs can be observed continuously. Herein, we examined the effect of one chewing cycle on energy metabolism of the masseter muscle in masticatory cycle using 31P-MRS.Measurements of 31P-MRS were performed on the center of human masseter muscle after determination of view point on transversal and saggital MR image. MRS parameter was detected in reasonable S/N ratio. But this measurement was difficult for low S/N ratio thought about according to motion artifact, and lower signal intensity of energy metabolism during masticatory movements. Additional program for 31P-MRS measurements in same mandibular position using rat is developed and that the program is applied to human was planned. with that purpose, the masseter from and the masseter weight are measured and the probe fitted for rat masseter was made. MRS measurements in rat masseter becomes possible enough hereby and this study can be to be gone along to measurements on same mandibular position in human freely chewing.