Simultaneous multislice acquisition without trajectory modification for hyperpolarized 13C experiments

Abstract

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.