Ultra-Short Echo-Time Based Accelerated Four-Dimensional Rosette J-resolved Spectroscopic Imaging (4D UTE-ROS-JRESI): A pilot study

Motivation: Two-dimensional spectrum resolves information-coupled metabolites along an additional spectral dimension. However, acquisition after adding the 2nd spectral encoding can increase the total acquisition time significantly. Goal(s): To achieve clinically feasible runtimes for J-resolved Spectroscopic Imaging (JRESI) using Ultra-Short Echo-Time (UTE) based sequence implementation. Approach: Implement a UTE based 4D JRESI sequence with rosette readout, which would enable shorter repetition times and use of higher undersampling factors. Results: This study demonstrated in-vivo 4D UTE-ROSE-JRESI in less than 10 minutes as compared to a semi-laser sequence with a TR of 1.5 seconds which will take 17 minutes for the same sequence. Impact: With higher incoherence level of sampling patterns rosette based spectroscopic imaging sequence showed the potential for highly accelerated acquisitions. Using UTE based rosette 4D J-resolved Spectroscopic Imaging sequence allowed further reduction in scan time with the help of shorter TR.