Optimization of real-time imaging sequences for MR-guided percutaneous needle interventions with implementation of MR-simulations

This thesis sought out to optimize real-time imaging sequences for MR-guided percutaneous needle interventions with implementation of MR-simulations. In the first objective of this thesis, contrast optimization was performed by simulating the spoiled gradient echo (GRE), balanced steady state free precession (bSSFP) and half-Fourier acquisition single-shot turbo spin-echo (HASTE) with various MR-parameters on a human patient. In the second objective of the study, simulations were compared with the contrast of an MR-experiment on an abdominal phantom with additional coaxial needle and cryoablation needle. MR-acquisitions of the spoiled GRE, bSSFP and HASTE sequence were simulated on a 3D-model of the abdominal phantom with added needle. Simulations of the bSSFP and HASTE for contrast optimization showed favorable lesion and tissue contrast compared to the spoiled GRE. Within the comparison between simulations and MR-experiment, no agreement in contrasts was observed. While lack of agreement between MR-simulations and MR-experiment was observed, the results within this work provide guidance in future optimization for the implementation of MR-simulations within MR-guided percutaneous interventions. Further work to improve the agreement between MR-simulations and the MR-environment encompass optimization of model inputs and optimization of external factors, influencing B0-homogeniety, within the Bloch-simulator.