Abstract
OBJECTIVE: This study presents the 3D MP-b-nSSFP sequence for multi-parametric mapping. METHODS: We evaluate several aspects of the 3D implementation, like the type of RF pulse (selective/non-selective), the readout duration, the undersampling pattern, and the acceleration factor. We use undersampled scans with subspace-constrained reconstruction and extended spiral readouts to achieve clinically acceptable scan times. The repeatability and accuracy of the T1 and T2 maps are compared with a reference technique in phantom and three volunteer scans. RESULTS: Compared with selective refocusing pulses, we observe lower bias with non-selective pulses, despite modeling the spatially varying effect of the pulses in the fitting process. T1 and T2 maps obtained from phantom scans were comparable to the nominal values and those from reference scans. T1 values in vivo were underestimated compared to the reference scan. The maps with an acquisition matrix of 256 × 256 × 44 and resolution 1 × 1 × 3 mm3 were acquired in 11 min. CONCLUSION: We show that 3D MP-b-nSSFP can be used for multi-parameter mapping within clinically acceptable scan time. Phantom scans show results in good agreement with reference scan results. However, the in vivo scan underestimated T1 .