TY - JOUR
T1 - NMR T1 measurements in inhomogeneous B1 with surface coils
AU - Evelhoch, Jeffrey L.
AU - Ackerman, Joseph J.H.
N1 - Funding Information:
Informative discussions with Richard W. Briggs are gratefully acknowledged. Support for this work was provided by Washington University Intramural Funds NSF Instrument Grant CH# 8100211 and NIH Grant 1 ROl GM3033 I-01 SSS. In addition, this project was also supported in part by BRSG SO7 RR07054-17, - 16, - 15 awarded by the Biomedical Research Support Grant Program, Division of Research Resources. National Institutes of Health. J.L.E. is a National Institutes of Health Postdoctoral Fellow.
PY - 1983/6/1
Y1 - 1983/6/1
N2 - Spin-lattice relaxation measurements with surface coils used in the single coil mode on stationary samples will produce accurate T1 values if a three-parameter exponential fit is employed. A further sufficient requirement is that the T1 measurement method (pulse sequence) conform to the following three criteria at all points in the sensitive volume of the surface coil. (i) The Z magnetization is consistently prepared to a nonequilibrium value at time zero. This initial condition must be the same at the start of every evolution period. (ii) After preparation, the magnetization is allowed to return toward thermal equilibrium during variable evolution periods τ. (iii) A constant fraction of the Z magnetization must then be sampled (observed) at the end of the evolution period. The inversion recovery, modified fast inversion recovery, and pulse-burst saturation recovery methods meet criteria (i)-(iii) and produce accurate T1 values with a surface coil. A brief survey of surface coil T1 measurements suggests that the greatest dynamic range is provided by using the inversion recovery or modified fast inversion recovery method, the pulse-burst saturation recovery method provides accurate T1 measurements in a minimum amount of time, and the use of composite pulses does not significantly improve the accuracy of the measurement.
AB - Spin-lattice relaxation measurements with surface coils used in the single coil mode on stationary samples will produce accurate T1 values if a three-parameter exponential fit is employed. A further sufficient requirement is that the T1 measurement method (pulse sequence) conform to the following three criteria at all points in the sensitive volume of the surface coil. (i) The Z magnetization is consistently prepared to a nonequilibrium value at time zero. This initial condition must be the same at the start of every evolution period. (ii) After preparation, the magnetization is allowed to return toward thermal equilibrium during variable evolution periods τ. (iii) A constant fraction of the Z magnetization must then be sampled (observed) at the end of the evolution period. The inversion recovery, modified fast inversion recovery, and pulse-burst saturation recovery methods meet criteria (i)-(iii) and produce accurate T1 values with a surface coil. A brief survey of surface coil T1 measurements suggests that the greatest dynamic range is provided by using the inversion recovery or modified fast inversion recovery method, the pulse-burst saturation recovery method provides accurate T1 measurements in a minimum amount of time, and the use of composite pulses does not significantly improve the accuracy of the measurement.
UR - http://www.scopus.com/inward/record.url?scp=0001770583&partnerID=8YFLogxK
U2 - 10.1016/0022-2364(83)90069-0
DO - 10.1016/0022-2364(83)90069-0
M3 - Article
AN - SCOPUS:0001770583
VL - 53
SP - 52
EP - 64
JO - Journal of Magnetic Resonance (1969)
JF - Journal of Magnetic Resonance (1969)
SN - 0022-2364
IS - 1
ER -