Concentric rings K-space trajectory for hyperpolarized (13)C MR spectroscopic imaging.

PURPOSE To develop a robust and rapid imaging technique for hyperpolarized (13)C MR Spectroscopic Imaging and investigate its performance. METHODS A concentric rings readout trajectory with constant angular velocity is proposed for hyperpolarized (13)C 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 (13)C phantoms and in vivo animal hyperpolarized (13)C 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 (13)C 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 (13)C MR Spectroscopic Imaging.