Ultrafast localized two-dimensional magnetic resonance correlated spectroscopy via spatially encoded technique

Purpose To speed up acquisition of localized two-dimensional (2D) correlated spectroscopy (LCOSY). Methods A new pulse sequence, dubbed as spatially encoded localized COSY (SLCOSY), based on spatially encoded technique, was developed for localized 2D correlated spectroscopy. It can be used to collect a full 2D spectrum in a single scan and thus on a subsecond timescale. Results SLCOSY spectrum of a two-compartment phantom was obtained with a total acquisition time of 773 ms, with its volume localization confirmed. Localized 2D COSY spectrum of a proton magnetic resonance spectroscopy brain phantom within 12 s shows the ability of SLCOSY to detect the metabolites at physiological concentrations. All 10 constituent metabolites in this phantom are reliably detected. SLCOSY spectrum of a sample of pig brain tissue with the acquisition time of 32 s demonstrates the feasibility of SLCOSY for the detection of biological tissues. Twelve pairs of cross peaks are identified. Conclusion The new method proposed herein enables ultrafast collection of a full 2D COSY spectrum, and it can also be used for fast in vivo analysis of metabolites, when signal-to-noise ratio is not a limiting factor.