MRI Sheds Its Shielding and Superconducting Magnets

MRI Sheds Its Shielding and Superconducting Magnets

Magnetic resonance imaging (MRI) has revolutionized healthcare by providing radiation-free, non-invasive 3-D medical images. However, MRI scanners often consume 25 kilowatts or more to power magnets producing magnetic fields up to 1.5 tesla. These requirements typically limits scanners’ use to specialized centers and departments in hospitals.

A University of Hong Kong team has now unveiled a low-power, highly simplified, full-body MRI device. With the help of artificial intelligence, the new scanner only requires a compact 0.05 T magnet and can run off a standard wall power outlet, requiring only 1,800 watts during operation. The researchers say their new AI-enabled machine can produce clear, detailed images on par with those from high-power MRI scanners currently used in clinics, and may one day help greatly improve access to MRI worldwide.

To generate images, MRI applies a magnetic field to align the poles of the body’s protons in the same direction. An MRI scanner then probes the body with radio waves, knocking the protons askew. When the radio waves turn off, the protons return to their original alignment, transmitting radio signals as they do so. MRI scanners receive these signals, converting them into images.

More than 150 million MRI scans are conducted worldwide annually, according to the Organization for Economic Cooperation and Development. However, despite five decades of development, clinical MRI procedures remain out of reach for more than two-thirds of the world’s population, especially in low- and middle-income countries. For instance, whereas the United States has 40 scanners per million inhabitants, in 2016 there were only 84 MRI units serving West Africa’s population of more than 370 million.

This disparity largely stems from the high costs and specialized settings required for standard MRI scanners. They use powerful superconducting magnets that require a lot of space, power, and specialized infrastructure. They also need rooms shielded from radio interference, further adding to hardware costs, restricting their mobility, and hampering their availability in other medical settings.

Scientists around the globe have already been exploring low-cost MRI scanners that operate at ultra-low-field (ULF) strengths of less than 0.1 T. These devices may consume much less power and prove potentially portable enough for bedside use. Indeed, as the Hong Kong team notes, MRI development initially focused on low fields of about 0.05 T, until the introduction of the first whole-body 1.5 T superconducting scanner by General Electric in 1983.

The new MRI scanner (top left) is smaller than conventional scanners, and does away with bulky RF shielding and superconducting magnetics. The new scanner’s imaging resolution is on par with conventional scanners (bottom).Ed X. Wu/The University of Hong Kong

Current ULF MRI scanners often rely on AI to help reconstruct images from what signals they gather using relatively weak magnetic fields….

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The post “MRI Sheds Its Shielding and Superconducting Magnets” by Charles Q. Choi was published on 05/15/2024 by