Small Magnets, Big Future: Low-Field MRI Technology and Clinical Utility

Abstract

Purpose: Despite the clinical advances made in magnetic resonance imaging with high static magnetic fields (1.5T and more), open MRI with low field (0.2-0.5T) has recently attracted the attention of researchers. Low-field MRI (LF-MRI) has both advantages and disadvantages over high-field units. It enables the scanning of anxious patients and children who cannot tolerate enclosed high-field scanners due to discomfort. The open configuration of the LF-MRI provides a spacious examination environment. It also allows the safe imaging of metallic devices owing to the lower static field and radiofrequency. While image quality is degraded compared to high-field MRI due to a lower signal-to-noise ratio, technological advances may help address this limitation. This review aims to provide a comprehensive outline of the current applications, technical aspects, and evidence supporting the diagnostic accuracy of Low-Field MRI. Materials and Methods: A literature search was conducted in Google Scholar and PubMed from 2021 to the oresent using the search term "low field MRI" limited to the title. Studies were excluded if only on high-field MRI, not in English, or conference abstracts without full text. After applying exclusion criteria, 32 relevant articles remained for analysis. Results: The results showed that portable low-field MRI expanded the availability of MRI beyond fixed facilities. One study found that 0.55T MRI had an accuracy similar to 1.5T for microbleed detection, suggesting its potential as an efficient alternative for stroke diagnosis. The literature has demonstrated the utility of low-field MRI in applications such as musculoskeletal, breast, and abdominal imaging. Conclusion: In conclusion, these studies demonstrated the potential of low-field MRI as a cost-efficient alternative to high-field MRI for several clinical applications. The reduced costs and accessibility afforded by low-field designs have positioned this technology to increase diagnostic MRI access globally. However, further validation of diagnostic performance and cost-utility analyses accounting for accuracy are still needed. Copyright © 2025 Tehran University of Medical Sciences.