Exploring Slowly Expanding Lesions in Pediatric-Onset Multiple Sclerosis

Detection of slowly expanding lesions (SELs) in pediatric-onset MS identifies a reproducible imaging correlate linked to accelerated tissue loss and worse structural outcomes on serial MRI — marking children at higher risk for early brain-volume change and related impairment.

In a multicenter pediatric-onset MS cohort, 52 participants underwent baseline and scheduled interval MRI (approximately every 6–12 months) with primary imaging endpoints of lesion expansion and brain atrophy. Presence of SELs correlated with greater brain-tissue loss and poorer clinical scores on longitudinal follow-up.

SEL detection and quantification used high-resolution 3D T1-weighted imaging with consistent slice geometry, companion T2-FLAIR for lesion burden, and susceptibility-weighted imaging to assist rim characterization. Longitudinal registration, lesion-masking, and parametric lesion-growth maps provided objective expansion metrics.

Pediatric-specific steps — shortened sequences, motion mitigation, age-appropriate coils, and standardized timing across visits — improved data quality and comparability for reliable SEL identification.