Development of a symmetric echo planar imaging framework for clinical translation of rapid dynamic hyperpolarized 13C imaging

PurposeTo develop symmetric echo planar imaging (EPI) and a reference scan framework for hyperpolarized C-13 metabolic imaging. MethodsSymmetric, ramp-sampled EPI with partial Fourier reconstruction was implemented on a 3T scanner. The framework for acquiring a reference scan on the H-1 channel and applied to C-13 data was described and validated in both phantoms and in vivo metabolism of [1-C-13]pyruvate. ResultsRamp-sampled, symmetric EPI provided a substantial increase in the signal-to-noise ratio of the phantom experiments. The reference scan acquired on the H-1 channel yielded C-13 phantom images that varied in mean signal intensity <2%, compared with C-13 images reconstructed with a reference scan directly measured on the C-13 channel. The structural similarity index and dynamic time course from in vivo C-13 data further support the application of a H-1 reference scan to C-13 data to mitigate Nyquist ghost artifacts. ConclusionRamp-sampled, symmetric EPI with spectral-spatial excitation of a single metabolite provides a fast, robust, and clinically efficacious approach to acquire hyperpolarized C-13 dynamic molecular imaging data. The gains of this efficient sampling, combined with partial Fourier methods, enables large matrix sizes required for human studies. Magn Reson Med 77:826-832, 2017. (c) 2016 International Society for Magnetic Resonance in Medicine