T1 discrimination contributions to proton magnetization transfer in heterogeneous biological systems
- 1 July 1994
- journal article
- Published by Wiley in Magnetic Resonance in Medicine
- Vol. 32 (1) , 16-22
- https://doi.org/10.1002/mrm.1910320104
Abstract
Water proton spin‐lattice relaxation times are commonly used as a guide in establishing the off‐resonance irradiation time as well as the repetition time of the magnetization transfer experiment. T1 discrimination effects occur if the motionally restricted spin bath longitudinal magnetization does not reach thermal equilibrium. In this study we developed the formalism necessary for the evaluation of T1 discrimination contributions to proton magnetization transfer arising from the use of a short repetition time relative to the spin‐lattice relaxation time of the motionally restricted spin bath. The results of computer simulation indicate that T1, discrimination contributions occur when the repetition time is small relative to the spin‐lattice relaxation time of the motionally restricted spin bath, and when the off‐resonance irradiation is weak and far off‐resonance. For somewhat longer repetition times, T1 discrimination contributions become important only when the cross relaxation rate is small, and the fractional amount of motionally restricted component large. The occurrence of T1 discrimination effects results in distortion of water proton intensity ratio dispersion curves thereby resulting in the estimation of erroneous magnetization transfer parameters, whereas in magnetization transfer contrast enhanced imaging, such contributions are manifested by a decrease in image contrast.Keywords
This publication has 7 references indexed in Scilit:
- Determination of proton magnetization transfer rate constants in heterogeneous biological systemsMagnetic Resonance in Medicine, 1994
- Quantitative interpretation of magnetization transferMagnetic Resonance in Medicine, 1993
- Transient decay of longitudinal magnetization in heterogeneous spin systems under selective saturationJournal of Magnetic Resonance (1969), 1992
- Incorporation of magnetization transfer into the formalism for rotating-frame spin-lattice proton NMR relaxation in the presence of an off-resonance-irradiation fieldJournal of Magnetic Resonance (1969), 1991
- Nuclear magnetic cross-relaxation spectroscopyJournal of Magnetic Resonance (1969), 1990
- Direct measurements of longitudinal relaxation and magnetization transfer in heterogeneous systemsJournal of Magnetic Resonance (1969), 1990
- [20] Protein rotational correlation times by carbon-13 rotating-frame spin-lattice relaxation in presence of off-resonance radiofrequency fieldPublished by Elsevier ,1989