oPtImal cOntrol magNetic Resonance Elastography :application to livEr with hemochRomatosis – PIONEER

Magnetic Resonance Elastography (MRE) is a non-invasive clinical tool for liver fibrosis characterization, yielding tissue stiffness values maps correlated to fibrosis stages. In the case of short T2 relaxation occurring in hemochromatosis, conventional MRE with its longer echo-time fails to deliver exploitable results due to a too low SNR. The liver is particularly affected in the case of hemochromatosis due to high iron deposition. If untreated the initial liver fibrosis can evolve to hepatocarcinoma with dire consequences for patients. Being able to properly assess the liver is therefore essential and doing so by MRI ideal since MRI is used for for non-invasive assessment of hepatic iron. Optimal Control (OC) MRE is a newly proposed alternative by our team, enabling higher SNR and coupled to ultra short echo-time (UTE) detection, evaluation of the stiffness of in vitro samples having T2 as low as 1 ms. OC-MRE is thus a technically suitable option and this project vows to produce an experimental demonstration of its applicability on hemochromatosis patients. To do so, the project is divided in different steps and the cornerstone is being able to apply OC-MRE on clinical MRIs. Until now, all developments have been carried out on pre-clinical MRIs having different technical specifications (field gradient strengths, RF amplitude etc...). A second challenge lies in accelerating the OC-MRE acquisition since using UTE detection leads to long acquisition time. Different K-space sampling will be considered and free-breathing acquisitions developed in particular with navigator sequences and dynamic slice positioning. Pre-clinical studies on mouse models will be carried out since they provide a good platform for clinical MRI developments that are contemplated. Once satisfactory preclinical and clinical in-vitro results are obtained, a feasibility study involving two hospital with two different vendor MRIs will be launched.