Portable ultra-low-field MRI in acute stroke care: A pilot study

Neuroimaging is a prerequisite for treatment of stroke patients, but it is not available all over the globe. Portable ultra-low field (pULF) MRI has the potential to improve access to neuroimaging and thus stroke care worldwide. In a pilot study, we were the first to utilise pULF-MRI in a European tertiary stroke centre and to evaluate its diagnostic value compared to high-field (HF) MRI.

Consecutive patients admitted for suspected ischaemic stroke underwent pULF-MRI using the 0.064 Tesla Swoop^® portable MR imaging system in addition to standard imaging. HF-MRI and pULF-MRI scans were blindly assessed to compare the diagnostic accuracy and imaging-based therapeutic decisions based on pULF-MRI to HF-MRI.

Seventeen patients underwent pULF-MRI, 12 of whom had ischaemic lesions on HF-MRI. Ischaemic lesions were detected on pULF-MRI in 8/12 cases. The four infarcts not identified on pULF-MRI were all smaller than 6 mm in diameter. In all cases, a virtual treatment decision based on pULF-MRI by a blinded team matched the actual clinical decisions.

This single-centre study demonstrates that pULF-MRI is a promising tool in acute stroke care, providing reliable imaging for treatment decision and follow-up monitoring. pULF-MRI may support acute stroke care if HF-MRI is unavailable and may be particularly helpful in resource-limited settings. Limitations of pULF-MRI include long acquisition times and the lack of vessel imaging and haemorrhage-sensitive sequences.