Physiologic basis of spin lattice relaxation time in normal rat tissues

The physical and biological mechanism of oxygen availability and oxygen consumption and its influence on proton spin-lattice relaxation time (T₁) in normal rat tissues is discussed. A systematic approach is used to find a correlation between T₁ and oxygen consumption rate. These data were abstracted from the literature and evaluated using a weighted-least-squares linear regression analysis. It is observed that T₁ values of normal rat tissues from different organs reveal a linear function of the oxygen consumption rate, with a correlation coefficient of 0.66. The relationship between water and T₁ yields no correlation. It is concluded that the variation of T₁ among different types of tissue depend on the rate at which paramagnetic molecular oxygen dissolved in the cell-associated water is consumed