Multi T1-weighted contrast imaging and T1 mapping with compressed sensing FLAWS at 3 T

Objective The Fluid And White matter Suppression (FLAWS) MRI sequence provides multiple T1-weighted contrasts of the brain in a single acquisition. However, the FLAWS acquisition time is approximately 8 min with a standard GRAPPA 3 acceleration factor at 3 T. This study aims at reducing the FLAWS acquisition time by providing a new sequence optimization based on a Cartesian phyllotaxis k-space undersampling and a compressed sensing (CS) reconstruction. This study also aims at showing that T1 mapping can be performed with FLAWS at 3 T.Materials and methods The CS FLAWS parameters were determined using a method based on a profit function maximization under constraints. The FLAWS optimization and T1 mapping were assessed with in-silico, in-vitro and in-vivo (10 healthy volunteers) experiments conducted at 3 T.Results In-silico, in-vitro and in-vivo experiments showed that the proposed CS FLAWS optimization allows the acquisition time of a 1 mm-isotropic full-brain scan to be reduced from 8mins to 6mins without decreasing image quality. In addition, these experiments demonstrate that T1 mapping can be performed with FLAWS at 3 T.Discussion The results obtained in this study suggest that the recent advances in FLAWS imaging allow to perform multiple T1-weighted contrast imaging and T1 mapping in a single 6mins sequence acquisition.

Automated summary

The study aims to reduce the acquisition time of FLAWS MRI sequence by using a new sequence optimization based on Cartesian phyllotaxis k-space undersampling and compressed sensing reconstruction. It also demonstrates that T1 mapping can be performed with FLAWS at 3T. In-silico, in-vitro, and in-vivo experiments show that the proposed optimization reduces the acquisition time of a 1mm-isotropic full-brain scan from 8mins to 6mins without decreasing image quality.