Portable ultra-low-field brain MRI: test-retest reliability and correspondence to high-field MRI

COEX 

Ultra-low-field MRI scanners offer a cost-effective and portable alternative to high-field neuroimaging. We aimed to quantify between-scanner test-retest reliability of 64mT brain scans, and their correspondence to 3T MRI. We scanned 23 healthy adult participants on two Hyperfine 64mT scanners and a GE 3T scanner using T1w and T2w scans at multiple resolutions. We segmented all images into 98 structures and estimated their volumes. We demonstrate excellent reliability of volumetric estimates from ultra-low-field MRI, and high correspondence to high-field scans. The highest reliability and high-field correspondence was obtained using T2w ultra-low-field scans, super-resolved by combining three orthogonal acquisitions with low through-plane resolution. This enables quantitative analysis of cost-effective and portable neuroimaging in various contexts, including low-resource environments.