Development of Magnetic Resonance Elastography for Measurement of the Material Properties of Abdominal Aortic Aneurysms

Speaker: Lyam Hollis, BHF CoRE PhD Student, The University of Edinburgh

Pizza at 12.45pm, talk starts at 1pm prompt.

Abstract:
Traditional imaging modalities such as MRI or CT focus predominantly on structure with such that patient specific models (PSM) are often well defined geometrically. In contrast measurement of material properties in vivo has proved more challenging resulting in input values that are often independent of the patient.

Magnetic resonance elastography (MRE) is an MRI-based technique that aims to characterise such properties. An external driver is used to induce shear waves into the region of interest (ROI) whilst a motion encoding gradient captures the resulting displacements. An  inversion algorithm is then used to create a map of the shear modulus (an elastogram). This project aims to develop MRE for use in abdominal aortic aneurysm (AAA) patients, incorporating measured material properties into PSMs of AAAs in order to improve predictions as to the risk of rupture.

Development of the technique has been performed largely in healthy volunteers where waves have been successfully induced into the aorta. Additionally the technique has been replicated in silico using finite element analysis (FEA) and the data integrated with the MRE post-processing software allowing testing of the software under highly controlled conditions. These simulations have been used to highlight limitations of the technique when wave propagation does not closely match the assumptions used to derive the inversion algorithm.