Diagnostic Efficacy, Costs and Safety of Portable Ultra-Low Field MRI in Brain Imaging: A Systematic Review

BACKGROUND: Portable ultra-low field MRI (ULF-MRI) has garnered significant attention in neuroimaging due to the high costs and accessibility issues associated with conventional high-field MRI (HF-MRI). This systematic review aims to explore the cost implications, safety issues and diagnostic capacity of ULF-MRI compared to HF-MRI in brain imaging while also examining its feasibility, limitations and challenges. METHOD: This systematic review followed Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. A comprehensive search was conducted across four databases: Medline, Embase, Scopus and the Global Health database. Additionally, the reference lists of studies identified through the database searches were examined. Studies were included if they involved brain imaging with ULF-MRI, used HF-MRI as a comparator and reported on costs, diagnostic accuracy, safety and/or feasibility. RESULTS: ULF-MRI has shown feasibility and applicability in diverse settings, including emergency departments, intensive care units and remote healthcare centres. Diagnostic capabilities have demonstrated good concordance with HF-MRI for various conditions, such as stroke (90% accuracy for ischaemic infarcts), multiple sclerosis (94% detection of lesions) and intracerebral haemorrhage (80.4-92.1% sensitivity). Challenges of ULF-MRI include a reduced signal-to-noise ratio and lower resolution, which can affect image quality and the detection of subtle lesions. CONCLUSION: While ULF-MRI has shown promising diagnostic accuracy for various neurological conditions, its lower image resolution limits the detection of subtle lesions, and it cannot yet replace HF-MRI. Continued technical advancements and further research are needed to improve image quality and promote broader clinical adoption.