The influence of motion on T1/T2 from cardiac-type phase-encoding direction

The authors report on a study to determine the effect of cardiac-type motion in the phase-encoding direction on the determination of T₁/T₂, th ratio of the tissue relaxation times, from multiecho spin-echo and inversion recovery nuclear magnetic resonance (NMR) data, with and without triggering. A motion phantom was designed to imitate the speed of heart wall motion. The phantom was also lined with material to simulate myocardial T ₁/T₂. It was found that neither oscillatory motion in the phase-encoding direction nor frequency variations significantly affect measurements of T₁ and T₂ as long as multiple data points are used and partial volumes with blood or other tissues are avoided