Sensitivity of portable low-field magnetic resonance imaging for multiple sclerosis lesions

• Published in: NeuroImage clinical 2022-01, Vol.35, p.103101, Article 103101
• Main Authors: Arnold, T. Campbell, Tu, Danni, Okar, Serhat V., Nair, Govind, By, Samantha, Kawatra, Karan D., Robert-Fitzgerald, Timothy E., Desiderio, Lisa M., Schindler, Matthew K., Shinohara, Russell T., Reich, Daniel S., Stein, Joel M.
• Format: Article
• Language: English
• Subjects: Adult; Brain - diagnostic imaging; Brain - pathology; Cross-Sectional Studies; Female; from the Special Issue on "Mapping Multiple Sclerosis: new frontiers - old challenges" Edited by Hartwig Siebner, Vanessa Wiggermann, Martina Absinta, Mark Mühlau, Oh Jiwon and Maria A. Rocca; Humans; Hyperfine; Low-field MRI; Magnetic Resonance Imaging - methods; Middle Aged; Multiple sclerosis; Multiple Sclerosis - pathology; Neuroimaging; Point-of-care MRI; Portable MRI; Prospective Studies; White matter lesions
• ISSN: 2213-1582; 2213-1582
• DOI: 10.1016/j.nicl.2022.103101

[Display omitted] •Paired, same-day, 3T and 64mT MRI studies were analyzed in 33 MS patients.•64mT MRI showed 94% sensitivity for detecting any lesions in 3T confirmed cases.•The diameter of the smallest detected lesion was larger at 64mT compared to 3T.•Total lesion volume estimates were strongly correlated between 3T and 64mT scans.•Portable low-field MRI detects white matter lesions, but smaller lesions may be missed. Magnetic resonance imaging (MRI) is a fundamental tool in the diagnosis and management of neurological diseases such as multiple sclerosis (MS). New portable, low-field strength, MRI scanners could potentially lower financial and technical barriers to neuroimaging and reach underserved or disabled populations, but the sensitivity of these devices for MS lesions is unknown. We sought to determine if white matter lesions can be detected on a portable 64mT scanner, compare automated lesion segmentations and total lesion volume between paired 3T and 64mT scans, identify features that contribute to lesion detection accuracy, and explore super-resolution imaging at low-field. In this prospective, cross-sectional study, same-day brain MRI (FLAIR, T1w, and T2w) scans were collected from 36 adults (32 women; mean age, 50 ± 14 years) with known or suspected MS using Siemens 3T (FLAIR: 1 mm isotropic, T1w: 1 mm isotropic, and T2w: 0.34–0.5 × 0.34–0.5 × 3–5 mm) and Hyperfine 64mT (FLAIR: 1.6 × 1.6 × 5 mm, T1w: 1.5 × 1.5 × 5 mm, and T2w: 1.5 × 1.5 × 5 mm) scanners at two centers. Images were reviewed by neuroradiologists. MS lesions were measured manually and segmented using an automated algorithm. Statistical analyses assessed accuracy and variability of segmentations across scanners and systematic scanner biases in automated volumetric measurements. Lesions were identified on 64mT scans in 94% (31/33) of patients with confirmed MS. The average smallest lesions manually detected were 5.7 ± 1.3 mm in maximum diameter at 64mT vs 2.1 ± 0.6 mm at 3T, approaching the spatial resolution of the respective scanner sequences (3T: 1 mm, 64mT: 5 mm slice thickness). Automated lesion volume estimates were highly correlated between 3T and 64mT scans (r = 0.89, p