Simultaneous multislice acquisition without trajectory modification for hyperpolarized 13C experiments

Purpose To investigate the feasibility of performing large FOV hyperpolarized 13C metabolic imaging using simultaneous multislice excitation. Methods A spectral‐spatial multislice excitation pulse was constructed by cosine modulation and incorporated into a 13C spiral imaging sequence. Phantom and in vivo pig experiments were performed to test the feasibility of simultaneous multislice data acquisition and image reconstruction. In vivo cardiac‐gated images of hyperpolarized pyruvate, bicarbonate, and lactate were obtained at 1 × 1 × 1 cm3 resolution over a 48 × 48 × 24 cm3 FOV with 2‐fold acceleration in the slice direction. Sensitivity encoding was used for image reconstruction with both autocalibrated and numerically calculated coil sensitivities. Results Simultaneous multislice images obtained with 2‐fold acceleration were comparable to reference unaccelerated images. Retained SNR figures greater than 80% were achieved over the part of the image containing the heart. Conclusion This method is anticipated to enable large FOV imaging studies using hyperpolarized 13C substrates, with an aim toward whole‐body exams that have to date been out of reach.