Partially spoiled gradient echo sequences for quantitative magnetic resonance imaging

• Applicant: Professor Dr. Herbert Köstler
• Subject Area: Medical Physics, Biomedical Technology
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 547784493

Magnetic resonance imaging (MRI) enables cross-sectional imaging of all body regions and has the advantage over alternative imaging methods that it is possible without the use of ionizing radiation. In clinical routine, qualitative methods, i.e. T1- or T2-weighted imaging, are typically used. Quantitative determinations of relaxation times would be desirable in many areas in order to objectify findings. In particular, it is hoped that the quantitative biomarkers T1 and T2 will provide early and objective insights to assess disease dynamics. Classical methods for the quantitative determination of relaxation times are typically more time-consuming than qualitative MRI, since the former requires multiple images to be acquired with different weightings. MR fingerprinting (MRF) allows the simultaneous determination of T1 and T2 from a large number of subsampled images of differently weighted transition states. Optimized MR fingerprinting sequences that take into account the effect of undersampling avoid frequent and rapid changes in excitation, essentially replacing the passage of many transition states by visiting fewer optimized steady states. Partially spoiled gradient echo sequences allow the establishment of T2-weighted equilibrium states and will thus allow the optimization of quantitative imaging in the future. The aim of this research project is to investigate, optimize, implement and validate partially spoiled steady state free precession sequences for quantitative magnetic resonance imaging with non-Cartesian trajectories. This includes T2 determination from a single steady state, combined T1 and T2 determination by using an IR sequence in conjunction with partial spoiling and finally MR fingerprinting with partial spoiling. In addition, the motion sensitivity of partially spoiled gradient echo sequences will also be systematically investigated. The optimized partially spoiled gradient echoes will enable rapid quantitative T2 determination and combined T1 and T2 determination as an objective biomarker in the future This sequences should enable quantitative, clinical MR imaging of the human abdomen and thorax as well as quantitative pediatric MRI in the future. In particular, they should also enable sequential examinations that allow to asses the dynamics of diseases at an early stage.

• DFG Programme: Research Grants