Determination of sample time for T1 measurement

In spin‐lattice relaxation time measurements, the relaxation time T1 is estimated from measuring the longitudinal magnetization during its return to thermal equilibrium from an initial (nonequilibrium) state. T1 estimation error depends on a number of factors, including the sample spacing, number of sample points, target T1 range, etc. We describe here a sample‐time determination method based on the principles of optimal experimental design. A two‐parameter model and a more general three‐parameter model of the general T1 measurement experiment are used in this study. Both linear and power‐law sample spacing strategies are evaluated. The proposed method formulates the sample‐time determination problem in closed form expressions that allow for easy calculation of optimum sample times, if a prior T1 estimate or a probable T1 distribution over the target range is given. Valuable insights can be gained from evaluation of these expressions concerning the relationship of T1 estimation error and the sample spacing, number of sample points, target T1 range, etc.

[1]  A. Crawley,et al.  A comparison of one‐shot and recovery methods in T1 imaging , 1988, Magnetic resonance in medicine.

[2]  A. Bax,et al.  Tip-angle-reduced T1 imaging , 1986 .

[3]  H. T. Edzes.  An analysis of the use of pulse multiplets in the single scan determination of spin-lattice relaxation rates , 1975 .

[4]  Optimization of Two-Stage Measurements of T1 , 1994 .

[5]  G. Weiss,et al.  The choice of optimal parameters for measurement of spin-lattice relaxation times. II. Comparison of saturation recovery, inversion recovery, and fast inversion recovery experiments , 1980 .

[6]  George H. Weiss,et al.  Two-Stage Inversion-Recovery Experiments for Measurements of T1 , 1993 .

[7]  D. Look,et al.  Time Saving in Measurement of NMR and EPR Relaxation Times , 1970 .

[8]  W. Dietrich,et al.  The analysis of spin-lattice relaxation time experiments , 1976 .

[9]  J C Gore,et al.  Toward an automated analysis system for nuclear magnetic resonance imaging. I. Efficient pulse sequences for simultaneous T1-T2 imaging. , 1986, Medical physics.

[10]  T. Foster,et al.  A review of normal tissue hydrogen NMR relaxation times and relaxation mechanisms from 1-100 MHz: dependence on tissue type, NMR frequency, temperature, species, excision, and age. , 1984, Medical physics.

[11]  G. Weiss,et al.  The choice of optimal parameters for measurement of spin-lattice relaxation times. IV: Effects of nonideal pulses , 1985 .

[12]  S. Silvey.  Optimal Design: An Introduction to the Theory for Parameter Estimation , 1980 .

[13]  A. Haase,et al.  NMR imaging of spin-lattice relaxation using stimulated echoes , 1985 .

[14]  W. J. Studden,et al.  Optimal Experimental Designs , 1966 .

[15]  Very Rapid Simultaneous Measurement of Nuclear Magnetic Resonance Spin-Lattice Relaxation Time and Spin-Spin Relaxation Time , 1991 .

[16]  The choice of optimal parameters for measurement of spin-lattice relaxation times. III. Mathematical preliminaries for nonideal pulses , 1985 .

[17]  Jonathan A. Jones,et al.  Optimal Sampling Strategies for the Measurement of Spin–Spin Relaxation Times , 1996 .

[18]  George H. Weiss,et al.  The choice of optimal parameters for measurement of spin-lattice relaxation times. I. Mathematical formulation , 1980 .

[19]  A. D. Bain.  The choice of parameters in an NMR experiment. Application to the inversion-recovery T1 method , 1990 .

[20]  Corwin L. Atwood,et al.  Optimal and Efficient Designs of Experiments , 1969 .

[21]  T. Carpenter,et al.  Consideration of random errors in the quantitative imaging of NMR relaxation , 1992 .

[22]  C. Hardy,et al.  A review of 1H nuclear magnetic resonance relaxation in pathology: are T1 and T2 diagnostic? , 1987, Medical physics.