In-vivo sodium triple quantum (TQ) MR signal extraction using a single-pulse sequence with single quantum time efficiency at 3T

Motivation: Detection of sodium TQ coherences, requires multi-pulse sequences combined with phase-cycling to suppress unwanted coherences, leading to non-feasible acquisition times in clinical settings. Goal(s): Development of a faster sodium TQ imaging method in the human brain at 3T. Approach: A radial multi-echo sequence is used to sample the temporal evolution of the sodium signal decay. The integral over the FID is computed to extract the TQ signal. Results: Acquisition of in-vivo 3D sodium TQ images with an apparent resolution of 6x6x6mm3 was achived within 30 minutes. Robustness of the method was demonstrated for simulation, phantom and in-vivo data against a state-of-the-art phase-cycling sequence. Impact: The method is readily applicable to any sodium studies that leverage a multi-echo sodium sequence and offers therefore, the potential to investigate multi-quantum coherences, potentially providing richer tissue characterization than tissue sodium concentration (TSC) alone.