Optimization of Signal Intensity and T1-Dependent Contrast with Nonstandard Flip Angles in Spin-Echo and Inversion-Recovery MR Imaging.

Theoretical expressions of flip angle values maximizing signal intensity and T1-dependent contrast are derived for spin-echo and inversion-recovery sequences. Experimental data and theoretical predictions are closely correlated for experiments carried out on phantoms, despite the nonideal shape of the RF refocusing pulse used for slice selection. The use of nonstandard angles is justified when rapid MR acquisitions are needed and/or large T1 species must be imaged with refocused sequences. Copyright 1998 Academic Press. Copyright 1998 Academic Press