Low-field MR Elastography in the liver and hepatic functional imaging

PhD candidate
Maksym Yushchenko

Prof. Najat Salameh
Prof. Markus Heim
Prof. Mathieu Sarracanie

Magnetic Resonance Imaging (MRI) enables high-resolution imaging of the human body with unmatched soft-tissue contrast in a completely non-invasive and non-ionizing manner.  Unfortunately, clinical MRI scanners operate at very high magnetic fields (1.5 T, 3 T) that increase their intrinsic sensitivity but also sensitize them to magnetic material in general, thus precluding  their use for a wide range of applications. Moving towards low magnetic fields (10-100 times lower than clinical scanners) provides unprecedented flexibility as MRI gains immunity to  magnetic susceptibility differences and becomes feasible in the presence of magnetic materials and environments such as those that can be found in iron overload disorders, or in patients with implanted devices.

The prevalence of chronic liver diseases (CLD) leading to cirrhosis is increasing worldwide and is the 12th leading cause of death in the United States. Cirrhosis can be avoided if fibrosis is diagnosed at early stages, when it is reversible. If not controlled, cirrhosis leads to hepato-carcinoma, liver failure, and death. CLD diagnosis with MRI is severely impaired when patients suffer from iron overload (up to 50% of patients). Magnetic resonance elastography (MRE) is a technique enabling remote palpation of the diseased organ not reachable by the clinician’s hand, and has shown very good results in diagnosing and staging CLDs. However, measuring the mechanical properties of the liver with MRI is less robust and can fail in the presence of iron overload. The Laboratory for Adaptable MRI Technology has been equipped with a very unique MRI scanner operating at 0.1 T, perfectly suited for safe MR imaging in routine diagnosis of CLDs without being impacted by the presence of iron content in human organs.

This PhD project consists in the installation of a unique low-magnetic field MRI research platform and in the development of a full pipeline for MRE applied to CLDs, from the development of innovative transducers inducing mechanical vibrations to the elaboration of fast MRE imaging sequences and image reconstruction. Two experimental setups will be designed and built, one for pre-clinical applications and the other one for testing in humans.