Improved precision in SASHA T₁ mapping with a variable flip angle readout

Excerpt

The SAturation-recovery single-SHot Acquisition (SASHA) T₁ mapping sequence has excellent accuracy independent of T₁, T₂, heart rate, and flip angle [1], which are known dependencies of the more commonly used MOdified Look-Locker Inversion-recovery (MOLLI) sequence. However, SASHA has a greater T₁ variability (poorer precision) compared to MOLLI. A two-parameter fit, with assumed ideal saturation, has been shown to improve precision compared to the standard three-parameter fit used for SASHA, but at the expense of introducing systematic errors [2]. We propose that a variable flip angle (VFA) readout will reduce these systematic errors and thereby allow the improved precision of a two-parameter fit while maintaining the accuracy of the three-parameter fit. …