Design of a sustainable prepolarizing magnetic resonance imaging system for infant hydrocephalus
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The need for affordable and appropriate medical technologies for developing countries continues to rise as challenges such as inadequate energy supply, limited technical expertise, and poor infrastructure persist. Low-field magnetic resonance imaging (LF MRI) is a technology that can be tailored to meet specific imaging needs within such countries. Its low power requirements and the possibility of operating in minimally shielded or unshielded environments make it especially attractive. Although the technology has been widely demonstrated over several decades, it is yet to be shown that it can be diagnostic and improve patient outcomes in clinical applications. We here demonstrate the robustness of prepolarizing MRI (PMRI) technology for assembly and deployment in developing countries for the specific application to infant hydrocephalus. Hydrocephalus treatment planning and management requires only modest spatial resolution, such that the brain can be distinguished from fluid—tissue contrast detail within the brain parenchyma is not essential.
Materials and Methods
We constructed an internally shielded PMRI system based on the Lee-Whiting coil system with a 22-cm diameter of spherical volume.
In an unshielded room, projection phantom images were acquired at 113 kHz with in-plane resolution of 3 mm × 3 mm, by introducing gradient fields of sufficient magnitude to dominate the 5000 ppm inhomogeneity of the readout field.
The low cost, straightforward assembly, deployment potential, and maintenance requirements demonstrate the suitability of our PMRI system for developing countries. Further improvement in image spatial resolution and contrast of LF MRI will broaden its potential clinical utility beyond hydrocephalus.
KeywordsHydrocephalus Prepolarization MRI Low field Ultra-low field
This work was funded by the Endowment funds of Harvey F. Brush at Penn State University, US Department of Energy Los Alamos National Laboratory Directed Research and Development program (IMS), and US National Institutes of Health Director's Pioneer Award 5DP1HD086071 (SJS).
JO: Responsible for winding magnet coils and carrying out imaging experiments. JRH: Responsible for solid work Computer Aided Designs (CAD) of the magnet and coil systems and for image analysis. SC: Responsible for theoretical analysis of magnetic field uniformity for the designs. ST: Participated in designing and building radio frequency amplifiers. TN: Participated in radio frequency tuning of coils, and contributed to image analysis. IMS: Consulted on all aspects of device design, wrote the labview program used in imaging, and helped carry out imaging experiments. SJS: Overall supervisor for the concept, design, implementation, and analysis for the project.
Compliance with ethical standards
Conflict of interest
Author IMS has received research support from the US Los Alamos National Laboratory’s Laboratory Directed Research and Development program. Author SJS has received support from the Endowment funds of Harvey F. Brush at Penn State University, and from the US NIH National Institutes of Health Director's Pioneer Award Grant 5DP1HD086071.
The study was conducted under the scientific ethics guidelines of The Pennsylvania State University, and in accordance with the use of US NIH funding. There were no human or animal research subjects. No study advertising was made and no remuneration was offered.
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