Rapid 3D whole-brain high-resolution T₁ quantification: Accelerating standard inversion recovery with...

An inversion recovery (IR) with an efficient three-dimensional (3D) readout for rapid whole-brain high-resolution T₁ quantification is highly desirable. The present work aims to propose and evaluate the IR-based T₁ mapping using stack-of-spirals turbo FLASH (SOS-TFL) acquisition.

The proposed IR sequence with multiple inversion times was preceded with a short saturation time (T_sat) and followed by a long 3D SOS-TFL readout. Its accuracy was evaluated through both a mixed doped-water and gel phantom and in vivo experiments by comparing protocols using varying T_sat values with a reference two-dimensional readout with a long T_sat. The performance of further acceleration was evaluated with different undersampling factors.

The fitted T₁ maps showed excellent agreement between the reference two-dimensional readout and 3D SOS-TFL acquisitions, as well as between those with no in-plane undersampling and those with prospectively moderate undersampling. This study demonstrated the feasibility of IR (8 inversion times)-based T₁ mapping equipped with 3D SOS-TFL acquisition to achieve whole-brain coverage with 1.0-mm isotropic resolution for 3-4 min, by using a short T_sat (2000 ms), a long echo train (1425 ms), and an easily achieved in-plane compressed-sensing acceleration factor (R = 3-4) combined with a through-plane sensitivity-encoding factor of 2.

This study demonstrates a fast whole-brain, high-resolution, IR-based T₁ mapping method with a vendor-provided 3D SOS-TFL readout. The acquisition was accelerated without the need for complex undersampling and reconstruction strategies. Its feasibility and accuracy were evaluated on a phantom and among healthy subjects.