Saturation recovery single‐shot acquisition (SASHA) for myocardial T1 mapping

Abstract

Purpose To validate a new saturation recovery single-shot acquisition (SASHA) pulse sequence for T₁ mapping and to compare SASHA T₁ values in heart failure patients and healthy controls. Theory The SASHA sequence consists of 10 electrocardiogram-triggered single-shot balanced steady-state free precession images in a breath-hold. The first image is acquired without magnetization preparation and the remaining nine images follow saturation pulses with variable saturation recovery times. Methods SASHA was validated through Bloch equation simulations, Monte Carlo simulations, and phantom experiments. Pre- and postcontrast myocardial and blood T₁ values were measured in 29 healthy volunteers and 7 patients with heart failure. Results SASHA T₁ values had excellent agreement (bias, 5 ± 5 ms) with spin echo experiments in phantoms with a wide range of physiologic T₁ and T₂ values and its accuracy was independent of flip angle, absolute T₁, T₂, and heart rate. The average baseline myocardial T₁ in heart failure patients was higher than in healthy controls (1200 ± 32 vs. 1170 ± 9 ms, P < 0.05) at 1.5T, as was the calculated blood–tissue partition coefficient, λ, (0.42 ± 0.04 vs. 0.38 ± 0.02, P < 0.05), consistent with diffuse myocardial fibrosis. Conclusions The SASHA sequence is a simple and fast approach to in vivo T₁ mapping with good accuracy in simulations and phantom experiments. Magn Reson Med 71:2082–2095, 2014.