Synchronous Multi-Directional Motion Encoding in Magnetic Resonance Elastography

The mechanical stiffness properties of biological tissue can be useful in the detection and diagnosis of disease, historically obtained through manual palpation. Magnetic Resonance Elastography (MRE) is a non-invasive method of obtaining mechanical properties of tissues inaccessible by palpation. By encoding the physical vibration applied to a tissue into the phase of its nuclear magnetic resonance signal, the physical displacement characteristics of a wave propagating the tissue can be measured. These wave characteristics can then be used to calculate relevant mechanical properties. Conventional MRE scans measure one direction of displacement at a time, requiring three lengthy scans to acquire full three-dimensional displacement data. This study investigates two novel techniques of acquiring multidirectional MRE data simultaneously: Selective spectral Displacement Projection (SDP) – MRE, and SampLe Interval Modulation (SLIM) – MRE. Both techniques are applied to previously-untested Siemens IDEA VB15 pulse sequencing software, verifying the modality-independence of the novel techniques. Additionally, displacement images and calculated stiffness maps for SDP-MRE and SLIM-MRE are compared to those of related conventional MRE scans to confirm that the time-saving innovations of the novel techniques have been implemented successfully.