Low field, high performance: Re-thinking the scanner to make MRI more accessible and more versatile

• Applicant: Dr. Christoph Maier
• Subject Area: Radiology
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 512359237

Magnetic resonance imaging (MRI) is a key tool in radiology and has become invaluable for the diagnosis and treatment monitoring of disease in virtually every field of medicine. But due to its high cost, only a small minority of the world population has access to this technology. MRI scanners are characterized by the strength of their magnetic field and conventionally, high field strength scanners are considered superior to low field devices in terms of image quality. Today, most clinical scanners operate at 1.5 Tesla or 3 Tesla. However, low field scanners are significantly cheaper to build and operate and recently, there has been re-newed interest in low-field MRI (field strength < 1 Tesla). The proposed research project aims to explore the potential of low-field MRI for diagnostic imaging. For this purpose, two MRI scanners will be trialled which operate at low field (0.55 Tesla and 0.06 Tesla) but which are equipped with high-end hardware components and advanced software for data acquisition and image reconstruction. The work program is divided into three objectives:Objective 1 is to develop methods to perform everyday examinations in radiology on low-field scanners with sufficient image quality. To achieve this, technical parameters of the imaging examinations will be adapted to specific physical characteristics of the low-field environment. Furthermore, a number of acceleration techniques will be deployed which have already been developed but which are not yet in widespread clinical use (e.g. compressed sensing and AI-based denoising). The brain and abdomen were selected as exemplary body regions. The motivation herein is to increase the overall value of MRI by opening it up to patient groups who currently do not have access to this technology (due to cost barriers or metallic implants which are incompatible with high field scanners).Objective 2 will address unmet clinical needs in lung imaging, which is a challenging organ for high field scanners. At low field, by contrast, physical conditions are advantageous due to favorable relaxation times and reduced susceptibility effects. These favorable conditions will be exploited in combination with the novel respiratory tracking technology "pilot tone" to deliver improved depiction of lung structure and quantitative measures of pulmonary physiology.Under Objective 3, the low-field platform will be put to use to investigate the cause of breathlessness in the emerging Long-Covid epidemic, building on the methodology developed under Objective 2. Serial low field lung MRI will be carried out in patients suffering from post-acute COVID-19 after hospital discharge, as well as in patients who recovered after hospital discharge, and in a control group who had never been hospitalized for COVID-19. MRI findings will be correlated with clinical data and with prior CT imaging obtained during acute disease. This objective is expected to continue after the two-year time frame of the proposed project.

• DFG Programme: WBP Fellowship
• International Connection: USA
• Host: Professor Dr. Hersh Chandarana