Introduction: To study the relationships between midbrain morphology, Loes score, gross motor function, and cognitive function in infantile Krabbe disease.
Methods: Magnetic resonance imaging (MRI) scans were evaluated by two neuroradiologists blinded to clinical status and neurodevelopmental function of children with early or late infantile Krabbe disease. A simplified qualitative 3-point scoring system based on midbrain morphology on midsagittal MRI was used. A score of 0 represented normal convex morphology of the midbrain, a score of 1 represented flattening of the midbrain, and a score of 3 represented concave morphology of the midbrain (hummingbird sign). Spearman correlations were estimated between this simplified MRI scoring system and the Loes score, gross motor score, and cognitive score.
Results: Forty-two MRIs of 27 subjects were reviewed. Analysis of the 42 scans showed normal midbrain morphology in 3 (7.1%) scans, midbrain flattening in 11 (26.2%) scans, and concave midbrain morphology (hummingbird sign) in 28 (66.7%) scans. Midbrain morphology scores were positively correlated with the Loes score (r = 0.81, p < 0.001) and negatively correlated with both gross motor and cognitive scores (r = -.84, p < 0.001; r = -0.87, p < 0.001, respectively). The inter-rater reliability for the midbrain morphology scale was κ = .95 (95% CI: 0.86-1.0), and the inter-rater reliability for the Loes scale was κ = .58 (95% CI: 0.42-0.73).
Conclusions: Midbrain morphology scores of midsagittal MRI images correlates with cognition and gross motor function in children with Krabbe disease. This MRI scoring system represents a simple but reliable method to assess disease progression in patients with infantile Krabbe disease.