Characterization of Portable Ultra-Low Field MRI Scanners for Multi-Center Structural Neuroimaging

Emil Ljungberg, Francesco Padormo, Megan Poorman, Petter Clemensson, Niall Bourke, John C Evans, James Gholam, Irene Vavasour, Shannon H Kollind, Samson L Lafayette, Carly Bennallick, Kirsten A Donald, Layla E Bradford, Beatrice Lena, Maclean Vokhiwa, Talat Shama, Jasmine Siew, Lydia Sekoli, Jeanne van Rensburg, Michael S PepperAmna Khan, Akber Madhwani, Frank A Banda, Mwila L Mwila, Adam R Cassidy, Kebaiphe Moabi, Dolly Sephi, Richard A Boakye, Kenneth A Ae-Ngibise, Kwaku P Asante, William J Hollander, Todor Karaulanov, Steven C R Williams, Sean Deoni

Research output: Contribution to journalArticlepeer-review

Abstract

The lower infrastructure requirements of portable ultra-low field MRI (ULF-MRI) systems have enabled their use in diverse settings such as intensive care units and remote medical facilities. The UNITY Project is an international neuroimaging network harnessing this technology, deploying portable ULF-MRI systems globally to expand access to MRI for studies into brain development. Given the wide range of environments where ULF-MRI systems may operate, there are external factors that might influence image quality. This work aims to introduce the quality control (QC) framework used by the UNITY Project to investigate how robust the systems are and how QC metrics compare between sites and over time. We present a QC framework using a commercially available phantom, scanned with 64 mT portable MRI systems at 17 sites across 12 countries on four continents. Using automated, open-source analysis tools, we quantify signal-to-noise, image contrast, and geometric distortions. Our results demonstrated that the image quality is robust to the varying operational environment, for example, electromagnetic noise interference and temperature. The Larmor frequency was significantly correlated to room temperature, as was image noise and contrast. Image distortions were less than 2.5 mm, with high robustness over time. Similar to studies at higher field, we found that changes in pulse sequence parameters from software updates had an impact on QC metrics. This study demonstrates that portable ULF-MRI systems can be deployed in a variety of environments for multi-center neuroimaging studies and produce robust results.

Original languageEnglish
Article numbere70217
Pages (from-to)e70217
JournalHuman Brain Mapping
Volume46
Issue number8
Early online date23 May 2025
DOIs
Publication statusPublished - 1 Jun 2025

Keywords

  • Magnetic Resonance Imaging/instrumentation
  • Humans
  • Neuroimaging/instrumentation
  • Phantoms, Imaging
  • Brain/diagnostic imaging
  • Quality Control
  • Image Processing, Computer-Assisted
  • Signal-To-Noise Ratio

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