New directions for brain MRI hardware and acquisition

The possibility of studying the living human brain with resolution, sensitivity and speed considerably above that provided by conventional MRI gradient encoding offers the potential to bring new levels of biology under the lens of non-invasive in vivo imaging. Although most academic MRI work focuses on software, the scanner hardware ultimately limits the capabilities of the technology. This talk will discuss our work toward improving MRI hardware at every level; magnet, detection, excitation encoding, gradient strength, B0 shimming and acquisition sequence efficiency with the goal of routinely studying laminar and columnar cortical structures as well as the constellation of small brain stem and mesencephalon structures typically ignored by functional imagers due to their small size and the difficulty of imaging in that part of the brain. Taken together these approaches have lead to a nearly 10 fold speed up of the functional MRI acquisition and the routine acquisition of whole brain functional data with a mm spatial resolution.
Finally, we note that the weight, power and cooling requirements of gradient coils as well as the magnet size/weight are barriers to using MRI in many locations such as an ambulance or rural health clinics as well as point-of-care situations, such as surgical recovery rooms. We have therefore developed a portable brain MRI system (<100 kg) which does not use traditional gradient coils at all, but encodes brain images by rotating an inhomogeneous magnet around the patient's head.