Applications, limitations and advancements of ultra-low-field magnetic resonance imaging: A scoping review

Abstract

Background: Ultra-low-field magnetic resonance imaging (ULF-MRI) has emerged as an alternative with several portable clinical applications. This review aims to comprehensively explore its applications, potential limitations, technological advancements, and expert recommendations.

Methods: A review of the literature was conducted across medical databases to identify relevant studies. Articles on clinical usage of ULF-MRI were included, and data regarding applications, limitations, and advancements were extracted. A total of 25 articles were included for qualitative analysis.

Results: The review reveals ULF-MRI efficacy in intensive care settings and intraoperatively. Technological strides are evident through innovative reconstruction techniques and integration with machine learning approaches. Additional advantages include features such as portability, cost-effectiveness, reduced power requirements, and improved patient comfort. However, alongside these strengths, certain limitations of ULF-MRI were identified, including low signal-to-noise ratio, limited resolution and length of scanning sequences, as well as variety and absence of regulatory-approved contrast-enhanced imaging. Recommendations from experts emphasize optimizing imaging quality, including addressing signal-to-noise ratio (SNR) and resolution, decreasing the length of scan time, and expanding point-of-care magnetic resonance imaging availability.

Conclusion: This review summarizes the potential of ULF-MRI. The technology's adaptability in intensive care unit settings and its diverse clinical and surgical applications, while accounting for SNR and resolution limitations, highlight its significance, especially in resource-limited settings. Technological advancements, alongside expert recommendations, pave the way for refining and expanding ULF-MRI's utility. However, adequate training is crucial for widespread utilization.

Keywords: Global health; Healthcare innovation; Medical imaging; Technology; Ultra-low-field magnetic resonance imaging.

Figure 1:

Preferred reporting items for systematic reviews and meta-analyses flow diagram.

Figure 2:

Countries on a world map where the studies were published.

Figure 3:

Study Designs included in the review.

Figure 4:

Publication dates of included studies.

Figure 5:

The Swoop® Portable Magnetic Resonance Imaging (MRI) System™ (Hyperfine, Inc., Guilford, CT, USA). This illustration showcases the practical utilization of the Hyperfine Swoop, a portable MRI scanner with low magnetic field strength, within a clinical context. The system’s mobility allows it to be transported to a patient’s bedside, where it can be connected to a standard wall outlet for power. The operation of the scanner is managed through a wireless tablet. The system boasts a field strength of 0.064T, employs a permanent magnet, and carries a weight of approximately 1400 pounds. On the Left: Connected to a power outlet and used through a wireless tablet. On the Right (Top and Bottom): Use of the system in a practical setting.