Interventional and susceptibility artifact-free MR Imaging
Third-party funded project
Project title Interventional and susceptibility artifact-free MR Imaging
Principal Investigator(s) Salameh, Najat
Project Members Sarracanie, Mathieu
Yushchenko, Maksym
Organisation / Research unit Departement Biomedical Engineering / Adaptable MRI Technology (Salameh)
Project start 01.05.2017
Probable end 30.04.2021
Status Active
Abstract

Medical imaging techniques have radically transformed the landscape of modern diagnosis and therapy by giving full access to the internal structure and function of the body. Magnetic Resonance Imaging (MRI), in particular, 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. In patients with implanted devices or iron overload, MRI is typically contraindicated and ionizing Computed Tomography (CT) or invasive biopsies can help, but do not suffice for accurate diagnosis or repetitive examinations as treatment follow-up. For interventional medicine, the interest in MRI monitoring is increasing but has difficulty to develop due to the many challenges posed by the presence of powerful magnets and radio frequency equipment inside an operating room. By design, MRI high-field magnets are not flexible and provide very little space for surgeons, and custom-designed, non-magnetic and non-electrically conductive equipment is mandatory to protect patients and staff from undesirable accidents. Furthermore, the compliance with non-magnetic environments is needed to ensure that scans are free from undesired image artifacts and severe signal losses. Typically found at interfaces (e.g. at air-tissue interfaces, in iron-overloaded tissues, or around implanted devices), magnetic susceptibility differences cause nuclear spins to lose coherence in magnetic field gradients and can result in image distortions, ghosting artifacts and dramatic signal losses.Operating at low magnetic fields, however, allows being much less sensitive and even immune to magnetic susceptibility changes, offers great flexibility for the design of open geometry scanners, and thus provides the ground for new applications not requiring a completely non-magnetic environment. In recent work, I have investigated new approaches that mitigate the substantial loss in sensitivity inherent to the low field regime, and showed the feasibility of high performance imaging. Low magnetic fields would permit MRI in the presence of iron or implanted devices, which is critical in the fields of iron-overloaded organs (like hemochromatosis) and image-guided therapies.

Keywords Low magnetic field MRI; Implanted devices; Iron overload; MR sequence development; MR hardware development; Interventional MRI; MR Elastography; MR-guided therapies; MRI; Magnetic susceptibility
Financed by Swiss National Science Foundation (SNSF)
   

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