Escanye J M, Canet D, Robert J
Biochim Biophys Acta. 1982 Nov 17;721(3):305-11. doi: 10.1016/0167-4889(82)90083-0.
We have measured the proton longitudinal relaxation times of tissue water of healthy and tumor-bearing mice as a function of the Larmor frequency in the range 6.7 to 90 MHz. These data can be rationalized according to T1-1 = A v -1/2 +B, where A and B are constants specific to the tissue species. We present an interpretation of this frequency dependence within the Fast Exchange Two States model. It is shown that involving a distribution of correlation times for water proton-proton interaction does not yield consistent results, whereas a physically meaningful translational diffusion model pertinent to the dipolar interaction between water protons and macromolecules protons leads to the required frequency dependence. Essentially tissues would differ by the 'bound' versus 'free' proportion, or by structural properties of cells, rather than by the time-scales governing water motion.
我们测量了健康小鼠和荷瘤小鼠组织水的质子纵向弛豫时间，其作为拉莫尔频率在6.7至90MHz范围内的函数。这些数据可以根据T1-1 = A v -1/2 +B进行合理化解释，其中A和B是特定于组织种类的常数。我们在快速交换双态模型中对这种频率依赖性进行了解释。结果表明，考虑水质子-质子相互作用的相关时间分布并不能产生一致的结果，而与水质子和大分子质子之间的偶极相互作用相关的具有物理意义的平移扩散模型则导致了所需的频率依赖性。本质上，组织之间的差异在于“结合”与“自由”的比例，或者细胞的结构特性，而不是控制水运动的时间尺度。
