Simultaneous T1 and T2 mapping of hyperpolarized 13C compounds using the bSSFP sequence

As in conventional H-1 MRI, T-1 and T-2 relaxation times of hyperpolarized (HP) C-13 nuclei can provide important biomedical information. Two new approaches were developed for simultaneous T-1 and T-2 mapping of HP C-13 probes based on balanced steady state free precession (bSSFP) acquisitions: a method based on sequential T-1 and T-2 mapping modules, and a model-based joint T-1/T-2 approach analogous to MR fingerprinting. These new methods were tested in simulations, HP C-13 phantoms, and in vivo in normal Sprague-Dawley rats. Non-localized T-1 values, low flip angle EPI T-1 maps, bSSFP T-2 maps, and Bloch-Siegert B-1 maps were also acquired for comparison. T-1 and T-2 maps acquired using both approaches were in good agreement with both literature values and data from comparative acquisitions. Multiple HP C-13 compounds were successfully mapped, with their relaxation time parameters measured within heart, liver, kidneys, and vasculature in one acquisition for the first time. (C) 2020 Elsevier Inc. All rights reserved.