Canine brain imaging with a new low-field portable (0.05 T) MRI scanner: a pilot in vivo comparison to conventional 1.5 T.

Prohibitive costs associated with high-field MRI systems have resulted in reduced access in resource-limited areas with consequential healthcare inequities. This has renewed interest in purposefully designed low-field (LF) systems that, despite inherently lower signal-to-noise ratios, have advantages in terms of cost, portability, and accessibility. This pilot study successfully translated a previously developed LF (0.05 T) MRI canine cadaver brain protocol for in vivo application and compared the acquired images with paired 1.5 T images from 21 different canine patients. The visibility of 15 anatomic features was ordinarily scored (scale 1-3) on transverse T1-weighted post-contrast (21/21 patients) and T2-weighted (17/21 patients) sequences. Lateral ventricles were easily visualized (89.3%-100% scored 3/3) across all sequence‒system combinations, with T2-weighted sequences also providing good identification of the mesencephalic aqueduct (56.3%-100%), fourth ventricle (77.1%-100%), and thalamus (68.8%-100%). Absolute visual grading characteristics (VGC) analysis confirmed comparable performance of the LF system to the 1.5 T MRI for these features, a particularly relevant finding given the system's originally intended application for pediatric hydrocephalus neuroimaging in resource-limited areas. This study represents the first in vivo usage and evaluation of a 0.05 T MRI in a clinical veterinary context.