Single-breath-hold abdominal T 1 mapping using 3D Cartesian Look-Locker with spatiotemporal sparsity constraints

摘要

Objective Our aim was to develop and validate a 3D Cartesian Look-Locker T 1 mapping technique that achieves high accuracy and whole-liver coverage within a single breath-hold. Materials and methods The proposed method combines sparse Cartesian sampling based on a spatiotemporally incoherent Poisson pattern and k-space segmentation, dedicated for high-temporal-resolution imaging. This combination allows capturing tissue with short relaxation times with volumetric coverage. A joint reconstruction of the 3D + inversion time (TI) data via compressed sensing exploits the spatiotemporal sparsity and ensures consistent quality for the subsequent multistep T 1 mapping. Data from the National Institute of Standards and Technology (NIST) phantom and 11 volunteers, along with reference 2D Look-Locker acquisitions, are used for validation. 2D and 3D methods are compared based on T 1 values in different abdominal tissues at 1.5 and 3 T. Results T 1 maps obtained from the proposed 3D method compare favorably with those from the 2D reference and additionally allow for reformatting or volumetric analysis. Excellent agreement is shown in phantom [bias~3T < 2%, bias1.5T < 5% for (120; 2000) ms] and volunteer data (3D and 2D deviation < 4% for liver, muscle, and spleen) for clinically acceptable scan (20 s) and reconstruction times (< 4 min). Conclusion Whole-liver T 1 mapping with high accuracy and precision is feasible in one breath-hold using spatiotemporally incoherent, sparse 3D Cartesian sampling.