T-1 rho dispersion of rat tissues in vitro

The purpose of this study was to demonstrate T1 rho dispersion in different rat tissues (liver, brain, spleen, kidney, heart, and skeletal muscle), an d to compare the I/T(1)rho data to previous 1/T-1 data and magnetization tr ansfer of rat tissues at low (0.1 T) B-0 field. The 1/T(1)rho dispersion sh owed a fairly similar pattern in all tissues. The highest 1/T(1)rho relaxat ion rates were seen in liver and muscle followed by heart, whereas the valu es for spleen, kidney, and brain were quite similar. Compared to 1/T-2 rela xation rate, the greatest difference was seen in liver and muscle. The rank order 1/T(1)rho value at each locking field B-1 was the same as the transf er rate of magnetization from the water to the macromolecular pool (Rwm) fo r liver, muscle, heart, and brain. The potential value T(1)rho imaging is t o combine high T-1 contrast of low field imaging with the high signal to no ise ratio of high static field imaging. When the T(1)rho value for a given tissue is known, the contrast between different tissues can be optimized by adjusting the locking time TL. Further studies are encouraged to fully exp loit this. Targets for more detailed research include brain infarct, brain and liver tumors, (C) 1999 Elsevier Science Inc.