Sharing GRAPPA calibration regions to accelerate quantitative imaging with phase-cycled bSSFP

Motivation: Quantitative imaging typically relies on repeated acquisitions of data with similar contrast. When combined with GRAPPA undersampling, repeatedly acquiring calibration regions may be redundant and prolong scan time. Goal(s): To demonstrate that a single acquisition of a calibration region is sufficient for multiparametric mapping. Approach: Undersampled phase-cycled bSSFP data were acquired and reconstructed using GRAPPA, using a single calibration region which was shared across contrasts and a repeated calibration region. Results were compared with fully sampled brain data obtained in healthy volunteers. Results: The acquisition of a single calibration region reduced scan time by ~30%, while T1 and T2 quantification was not affected. Impact: Shared calibration region data across repeated acquisitions in quantitative parametric mapping sequences, significantly accelerates quantitative imaging without compromising image quality.