Advancements in abdominal MR elastography

Magnetic Resonance Elastography (MRE) is a quantitative imaging technique that makes use of an external vibration and a phase-locked MR sequence to measures biomechanical properties of soft tissue. These MRE-measured biomechanical properties can give insight in the stiffness of various malignancies which may impact treatment. This thesis investigates applications in pancreatic ductal adenocarcinoma (PDAC) and in Crohn's Disease (CD).
The research examines different bowel preparation methods to optimize MRE quality in the pancreas, concluding that a simple fasting regimen is effective and less burdensome. MRE demonstrated significant differences in viscoelastic properties between healthy and diseased tissues, suggesting the potential to distinguish various tissue types.
The thesis also underscores the necessity of validating MRE results through ex vivo biomechanical testing. Moderate to good correlations between in vivo MRE and ex vivo measurements support MRE's utility in measuring tumor elasticity, establishing it as a reliable predictive biomarker.
A novel single breath-hold MRE technique was developed and tested, showing comparable results to traditional multiple breath-holding and enabling the differentiation between healthy and PDAC tissues. Furthermore, motion correction strategies in free-breathing abdominal MRE were explored, revealing that motion correction enhances data quality, inversion precision, and repeatability. These improvements are crucial for accurate viscoelastic measurements.
Finally, the feasibility of using MRE to assess viscoelastic properties of the mesentery in CD patients was studied, revealing significant differences compared to healthy volunteers and strong correlations with mesenteric fibrosis. MRE thus shows promise in guiding surgical decisions. Overall, this thesis highlights MRE's potential and challenges in innovative clinical applications.