RAPID SPIRAL CSI IMAGING USING CG RECONSTRUCTION

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Spiral chemical shift imaging (CSI) reduces the scan time of a CSI experiment by acquiring the time domain data while playing out spiral gradient waveforms along two spatial dimensions. This achieves the simultaneous encoding of both spatial and spectral information and theoretically permits the acquisition of a complete 2D CSI data set with a single excitation. However, for most applications, limitations on maximum gradient strength and slew rate usually make multiple excitations necessary in which either the start of the data acquisition is shifted (spectral interleaves) or the spiral k-space trajectories are rotated (spatial interleaves). Gradient limitations are even more a problem at higher field strength because of the increased dispersion of the chemical shift. While parallel imaging techniques are commonly used even in non-Cartesian imaging to speed up the acquisition, so far, they have been only applied to CSI using conventional phase encoding and echo planar spectroscopic imaging. A rapid readout is of particular relevance in molecular imaging applications using C13-labelled tracers. Here, a rapid acquisition helps to image tissue like the myocardium and also allows one to better monitor the kinetics how C13-tracers gets metabolized.