31P Spin‐Lattice Relaxation Times and Resonance Linewidths of Rat Tissue in Vivo: Dependence upon the Static Magnetic Field Strength

Abstract
Phosphorus‐31 NMR spin‐lattice relaxation times and resonance linewidths of rat leg muscle, brain, and liver metabolites in vivo have been examined at 1.9‐, 4.7‐, and 8.5‐ T static magnetic field strengths. The resonance linewidths expressed in ppm that have been measured are independent of field strength. The spin‐lattice relaxation times of muscle and brain phosphorus metabolites decrease linearly with increasing field strength while those of liver are constant over the range of static fields examined.