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The Effect of Magnetic Field Inhomogeneity on the Transverse Relaxation of Quadrupolar Nuclei Measured by Multiple Quantum Filtered NMR
Ist Teil von
Journal of magnetic resonance (1997), 1997-09, Vol.128 (1), p.82-86
Ort / Verlag
Elsevier Inc
Erscheinungsjahr
1997
Quelle
Access via ScienceDirect (Elsevier)
Beschreibungen/Notizen
The effects of magnetic fieldsB0andB1inhomogeneities on techniques which are commonly used for the measurements of triple-quantum-filtered (TQF) NMR spectroscopy of23Na in biological tissues are analyzed. The results of measurements by pulse sequences with and without refocusing ofB0inhomogeneities are compared. It is shown that without refocusing the errors in the measurement of the transverse relaxation times by TQF NMR spectroscopy may be as large as 100%, and thus, refocusing of magnetic field inhomogeneity is mandatory. Theoretical calculations demonstrate that without refocusingB0inhomogeneities the spectral width and phase depend on the interpulse time intervals, thus, leading to errors in the measured relaxation times. It is shown that pulse sequences that were used for the refocusing of the magnetic field (B0) inhomogeneity also reduce the sensitivity of the experimental results to radiofrequency (B1) magnetic field inhomogeneity.