Murase N, Watanabe T
Laboratory of Chemistry, Faculty of Science and Engineering, Tokyo Denki University, Saitama, Japan.
Magn Reson Med. 1989 Jan;9(1):1-7. doi: 10.1002/mrm.1910090102.
Nuclear magnetic relaxation measurements of water in gels made of crosslinked dextran or polyacrylamide (water content, 30-60 wt%) were carried out using broad-line proton-pulsed NMR. Both T1 and T2 values showed inflection against pore size, i.e., the size of the compartment made by crosslinks of the polymer gels. T2 (or T1) values obtained for gels with compartments smaller than the critical size remained low within the range of the water content used in this experiment. Those values of gels with larger compartments, on the other hand, became higher with increasing size. When the size of the compartment was larger than the critical size, T1 and T2 values also became higher with increasing water content. The inflection point can be considered to correspond to the critical compartment size below which the motion of compartmentalized water in gels is more or less restricted. When the compartment is small, however, not only the effect of the molecular motion of water but also that of the proton exchange between compartmentalized water and gel matrix or hydration water should be taken into consideration for the interpretation of the short relaxation times observed, especially by T2. The results obtained in this investigation might provide useful information in the explanation and evaluation of the relaxation values in tissue.
使用宽线质子脉冲核磁共振对由交联葡聚糖或聚丙烯酰胺制成的凝胶（含水量30 - 60 wt%）中的水进行了核磁共振弛豫测量。T1和T2值均随孔径（即由聚合物凝胶交联形成的隔室大小）出现拐点。对于隔室小于临界尺寸的凝胶，在本实验所用含水量范围内，T2（或T1）值保持较低。另一方面，对于隔室较大的凝胶，这些值随尺寸增大而升高。当隔室尺寸大于临界尺寸时，T1和T2值也随含水量增加而升高。该拐点可被认为对应于临界隔室尺寸，低于此尺寸时，凝胶中分隔水的运动或多或少受到限制。然而，当隔室较小时，在解释所观察到的短弛豫时间（尤其是T2）时，不仅要考虑水的分子运动影响，还要考虑分隔水与凝胶基质或水化水之间质子交换的影响。本研究获得的结果可能为解释和评估组织中的弛豫值提供有用信息。
