GAGA: Gapped Arrangement of Golden Angles for sliding window reconstruction of hyperpolarized dynamic 13C MRSI data acquired with 3D radial EPSI

Motivation: Hyperpolarized 13C magnetic resonance spectroscopic imaging (13C-MRSI) provides real-time metabolic insights but requires extremely fast and efficient imaging sequences, especially for dynamic measurements. Goal(s): This work aims to enhance three-dimensional 13C radially-sampled echo-planar spectroscopic imaging (rEPSI) to enable dynamic acquisitions. Approach: A novel algorithm for a 3D Gapped Arrangement of Golden Angles (GAGA) is introduced, combined with sliding window (SW) reconstruction, and tested in simulation and phantom studies. Results: The algorithm developed for GAGA creates homogeneous k-space sampling distributions for individual temporal subframes, and SW reconstruction successfully recovers the temporal dynamics while displaying only minor temporal flickering and incoherent undersampling artifacts. Impact: The novel algorithm for a Gapped Arrangement of Golden Angles (GAGA) enables dynamic measurements of volumetric hyperpolarized 13C MRSI with a high temporal resolution. Further studies will exploit its potential for the investigation of metabolic processes using dynamic hyperpolarized 13C-MRSI.