During the past year we performed first human cardiovascular MRI using a novel low-field and high-performance MRI system at 0.55T. The system preserves imaging with reduced SAR which allows MRI catheterization using conductive metallic cardiovascular guidewires. These allow using fundamental metallic catheter tools without dangerous heating. In collaboration with the laboratory of Adrienne Campbell-Washburn we are helping to characterize fundamental MR properties of tissues of interest at low field. We demonstrated the value of ferumoxytol (polysaccharide coated iron oxide nanoparticles) for indicator-dilution measurement of blood pool, validated against carbon monoxide in large mammals. This may prove a useful measure in patients with different hear failure phenotypes. We have investigated the value of low-field high-performance MRI to image iron susceptibility markers for guidewire tracking and navigation. We have explored the ability of real-time MRI at low field (0.55T) to visualize acute myocardial injury from radiofrequency ablation (RFA) and from chemoablation using ethanol or acetic acid. Preliminary data suggests acute injury from RFA is difficult to image in real-time across field strengths. By contrast, chemoablation lesions are readily visualized using real-time MRI. These findings will enable novel treatments for structural heart disease and rhythm disorders including MRI catheterization. We are working closely with industry, through a Collaborative Research and Development Agreement, system for safe patient hemodynamic monitoring and recording during interventional MRI experiments and during transfer between X-ray and MRI. We are working closely with industry to transfer our developments into commercial tools that can be used widely in medical care throughout the world.
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