On‐site construction of a point‐of‐care low‐field MRI system in Africa

Abstract

To describe the construction and testing of a portable point-of-care low-field MRI system on site in Africa.Methods: All of the components to assemble a 50 mT Halbach magnet-based system, together with the necessary tools, were air-freighted from the Netherlands to Uganda. The construction steps included individual magnet sorting, filling of each ring of the magnet assembly, fine-tuning the inter-ring separations of the 23-ring magnet assembly, gradient coil construction, integration of gradient coils and magnet assembly, construction of the portable aluminum trolley and finally testing of the entire system with an open source MR spectrometer.Results: With four instructors and six untrained personnel, the complete project from delivery to first image took approximately 11 days.Conclusions: An important step in translating scientific developments in the western world from high-income industrialized countries to low-and middle-income countries (LMICs) is to produce technology that can be assembled and ultimately constructed locally. Local assembly and construction are associated with skill development, low costs and jobs. Point-of-care systems have a large potential to increase the accessibility and sustainability of MRI in LMICs, and this work demonstrates that technology and knowledge transfer can be performed relatively seamlessly.

Low‐field MRI: A report on the 2022 ISMRM workshop

“…18 Johnes Obungoloch provided a valuable perspective on the deployment of low-field MRI technology in Africa where there are fewer than three MRI devices available in most countries. 19 To increase access, he suggested developing systems, such as Halbach arrays, 20 that can be built, installed, and maintained with local expertise; establishing local manufacturing capacity and training; developing systems that are inexpensive and flexible; understanding local infrastructure constraints such as low power requirements and power instability; cultivating multi-national multi-disciplinary teams; and advocating to local governments for support. 2,21,22 Session 2 focused on the dissemination of low-field MRI technology.…”

“…These magnet designs can reduce expense more dramatically, for example, by an order of magnitude compared to 1.5T 23 . For example, a home‐built 50 mT Halbach array system has been reported to cost <€15 000 for only the material and production costs, with almost no siting requirements 20 . Currently marketed portable point‐of‐care units cost more than this, but they require fewer financial resources in terms of siting and maintenance.…”

Characterization of concomitant gradient fields and their effects on image distortions using a low‐field point‐of‐care Halbach‐based MRI system

“…x , G r y , G r z ] T the gradient vector during frequency encoded data-acquisition. Assuming that the phase encoding gradients are applied for 𝜏 seconds, the resulting magnetization is given by m pe ∶= m(g pe , 𝜏) = 𝜌(r ′ ) P e −j𝛾|B(g pe )|S𝜏 P H m0 , (8) with P = X(g pe ). Furthermore, after the phase encoding step, the magnetization during data-sampling can be written as…”

“…Recently, there has been significant interest in low‐field point‐of‐care (POC) MRI systems 1‐4 which can be used in environments where MRI is currently lacking: examples include the intensive care unit, 5,6 the emergency room, and regions in low‐ and middle‐income countries with limited financial and infrastructural resources 7,8 . These low‐field systems typically have magnetic fields between approximately 40 and 80 mT, run on mains power and do not use cooling.…”

Rapid quantification of alcohol content in intact bottles of wine using J-coupled spectroscopy in an inhomogeneous low field magnet

“…Low-eld portable MRI has seen a recent renaissance (1)(2)(3) with the increased social awareness that clinical MRI scans are available as a diagnostic disease tool to less than 30% of the worldwide population (4)(5)(6). Our group constructed a number of Halbach-based systems (7,8) consisting of thousands of small permanent magnets (9,10), and have even fabricated one on-site with colleagues in Mberara in Uganda (11). Other research groups have used or designed systems with two large permanent magnet poles connected by one or two yokes (12)(13)(14).…”