Concentric Rings K-Space Trajectory for Hyperpolarized 13C MR Spectroscopic Imaging

Purpose: To develop a robust and rapid imaging technique for hyperpolarized C-13 MR Spectroscopic Imaging and investigate its performance. Methods: A concentric rings readout trajectory with constant angular velocity is proposed for hyperpolarized C-13 spectroscopic imaging and its properties are analyzed. Quantitative analyses of design tradeoffs are presented for several imaging scenarios. The first application of concentric rings on C-13 phantoms and in vivo animal hyperpolarized C-13 MR Spectroscopic Imaging studies were performed to demonstrate the feasibility of the proposed method. Finally, a parallel imaging accelerated concentric rings study is presented. Results: The concentric rings MR Spectroscopic Imaging trajectory has the advantages of acquisition timesaving compared to echo-planar spectroscopic imaging. It provides sufficient spectral bandwidth with relatively high efficiency compared to echo-planar spectroscopic imaging and spiral techniques. Phantom and in vivo animal studies showed good image quality with half the scan time and reduced pulsatile flow artifacts compared to echo-planar spectroscopic imaging. Parallel imaging accelerated concentric rings showed advantages over Cartesian sampling in g-factor simulations and demonstrated aliasing-free image quality in a hyperpolarized C-13 in vivo study. Conclusion: The concentric rings trajectory is a robust and rapid imaging technique that fits very well with the speed, bandwidth, and resolution requirements of hyperpolarized C-13 MR Spectroscopic Imaging. (C) 2014 Wiley Periodicals, Inc.