5D Echo-planar J-resolved spectroscopic imaging of cerebral metabolites in HIV-infected youth: a preliminary study

Purpose: Perinatally HIV-infected youths have abnormal cerebral metabolite concentrations, but this has not been well studied. By incorporating a varying TE, 2D J-resolved spectroscopy reduces spectral crowding by pushing multiplet splittings into a second spectral dimension. Multivoxel MR Spectroscopic Imaging (MRSI) can be used to obtain spectra throughout the brain, providing better coverage than single voxel techniques. An echo planar readout allows the interleaved acquisition of 1 spatial and 1 spectral dimension, greatly accelerating scan time. Nonuniform sampling (NUS) can be used on the incrementally acquired dimensions ky, kz, and t1 to further accelerate scan time . Previous studies have been limited mostly to single voxel 1D or 2D MRS acquisitions and are therefore limited in their spatial coverage. A goal of this study was to evaluate a recently implemented 5D NUS echo-planar J-resolved Spectroscopic Imaging (EP-JRESI) in HIV Youth and age-matched healthy children and also, to investigate the reproducibility of metabolite quantitation using adult healthy volunteers.