A low-cost and shielding-free ultra-low-field brain MRI scanner

Abstract

Magnetic resonance imaging is a key diagnostic tool in modern healthcare, yet it can be cost-prohibitive given the high installation, maintenance and operation costs of the machinery. There are approximately seven scanners per million inhabitants and over 90% are concentrated in high-income countries. We describe an ultra-low-field brain MRI scanner that operates using a standard AC power outlet and is low cost to build. Using a permanent 0.055 Tesla Samarium-cobalt magnet and deep learning for cancellation of electromagnetic interference, it requires neither magnetic nor radiofrequency shielding cages. The scanner is compact, mobile, and acoustically quiet during scanning. We implement four standard clinical neuroimaging protocols (T1- and T2-weighted, fluid-attenuated inversion recovery like, and diffusion-weighted imaging) on this system, and demonstrate preliminary feasibility in diagnosing brain tumor and stroke. Such technology has the potential to meet clinical needs at point of care or in low and middle income countries.

Portable, low-field magnetic resonance imaging enables highly accessible and dynamic bedside evaluation of ischemic stroke

“…In contrast to high-field MRI, low-field MRI technologies are a significantly more affordable imaging modality. This relates to the reduced cost of manufacturing, maintenance and operation ( 41 ). The low magnetic field strength of the pMRI also enables the device to be operated in environments containing ferromagnetic material and integrates electromagnetic interference rejection ( 42 ), removing the need for cost-prohibitive MRI suites.…”

Off-resonance artifact correction for magnetic resonance imaging: a review

“…com). Academic groups have created permanent magnet designs using cylindrical Halbach geometries [27,28,29], dipole magnet geometries [19,18], and single sided designs [30]. Unlike superconducting magnets, these scanners have field homogeneities in the range of tens of ppm (for smaller FOV extremity imaging) to hundreds or thousands of ppms for head imaging, but have been shown to successfully image human subjects [20,21,19,18].…”

“…It is also important to consider off-resonance artifacts and potential correction strategies when working with MRI scanners that have more inhomogeneous B 0 fields than high-field superconducting magnets. Recently, there have been many advances in portable MRI at lower fields to perform in vivo human imaging [18,19,20,21,22]. These new technologies are important for increasing the accessibility of MRI [23], but they generally have less uniform B 0 fields than superconducting magnets and off-resonance correction approaches are needed.…”

Benchmarking the performance of a low-cost Magnetic Resonance Control System at multiple sites in the open MaRCoS community

“…These achievements are enabled by a new generation of scanners combining refined hardware engineering with powerful computational algorithms, including machine learning architectures. Improvements are being integrated in all engineering and imaging stages: during the scanner design process [24]- [26], for pulse sequence design [18], during signal acquisition [15], for image reconstruction [19], [27], and for data analysis and image postprocessing [28].…”