Model‐based reconstruction for simultaneous multi‐slice T1 mapping using single‐shot inversion‐recovery radial FLASH

Purpose To develop a single‐shot multi‐slice T1 mapping method by combing simultaneous multi‐slice (SMS) excitations, single‐shot inversion‐recovery (IR) radial fast low‐angle shot (FLASH), and a nonlinear model–based reconstruction method. Methods SMS excitations are combined with a single‐shot IR radial FLASH sequence for data acquisition. A previously developed single‐slice calibrationless model–based reconstruction is extended to SMS, formulating the estimation of parameter maps and coil sensitivities from all slices as a single nonlinear inverse problem. Joint‐sparsity constraints are further applied to the parameter maps to improve T1 precision. Validations of the proposed method are performed for a phantom and for the human brain and liver in 6 healthy adult subjects. Results Phantom results confirm good T1 accuracy and precision of the simultaneously acquired multi‐slice T1 maps in comparison to single‐slice references. In vivo human brain studies demonstrate the better performance of SMS acquisitions compared to the conventional spoke‐interleaved multi‐slice acquisition using model‐based reconstruction. Aside from good accuracy and precision, the results of 6 healthy subjects in both brain and abdominal studies confirm good repeatability between scan and re‐scans. The proposed method can simultaneously acquire T1 maps for 5 slices of a human brain ( 0.75×0.75×5mm3) or 3 slices of the abdomen ( 1.25×1.25×6mm3) within 4 seconds. Conclusions The IR SMS radial FLASH acquisition together with a nonlinear model–based reconstruction enable rapid high‐resolution multi‐slice T1 mapping with good accuracy, precision, and repeatability.