Heterogeneity of muscle fat infiltration in children with spina bifida.
Water-fat MRI spots hidden muscle fat in spina bifida and links tightly to real strength, outshining basic tests.
01Research in Context
What this study did
Doctors scanned the leg muscles of children with spina bifida. They used a special MRI that separates water and fat signals.
The scan gave a clear picture of how much fat had crept into each muscle. The team also tested leg strength by hand.
They wanted to know if the MRI numbers matched what the old strength test showed.
What they found
The MRI fat scores were very steady when two doctors measured the same scan.
More fat inside a muscle meant weaker strength on the hand test.
Some muscles looked almost normal while neighbors were full of fat, showing hidden uneven damage.
How this fits with other research
Wagels et al. (2020) pooled 19 studies on cerebral palsy and found that brain scans also predict arm function. Both papers say: look past the surface.
Perez et al. (2015) tried the same idea in CP but saw only weak links between MRI damage and walking skill. Their pictures were plain MRIs, not the new water-fat kind, so they missed the fine muscle detail.
Cummings et al. (2024) report that plain BMI tells us nothing about motor skill in youth with intellectual disability. Koegel et al. (2014) show that a deeper MRI fat read-out does relate to strength, giving you a sharper tool than weight alone.
Why it matters
If you serve kids with spina bifida, ask the medical team for water-fat MRI reports. The numbers show which muscles are quietly fading before you see a strength drop. Use the fat scores to pick leg braces, set gait goals, and prove that therapy keeps muscle quality, not just strength.
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Join Free →Request the radiology report and circle the fat fraction numbers; write leg-strength goals that match the worst fat scores first.
02At a glance
03Original abstract
Children with spina bifida have well recognized functional deficits of muscle, but little is known about the associated changes in muscle anatomy and composition. This study used water-fat magnetic resonance imaging (MRI) to measure fat infiltration in the lower extremity muscles of 11 children with myelomeningocele, the most severe form of spina bifida. MRI measurements of muscle fat fraction (FF) were compared against manual muscle test (MMT) scores for muscle strength. The FF measurements were objective and reliable with mean inter-rater differences of <2% and intraclass correlation coefficients>0.98. There was a significant inverse relationship between muscle FF and MMT scores (P ≤ 0.001). Surprisingly, however, muscles with negligible strength (MMT 0-1) exhibited a bimodal distribution of FF with one group having FF>70% and another group having FF<20%. The MRI also revealed striking heterogeneity amongst individual muscles in the same muscle group (e.g., 4% fat in one participant's lateral gastrocnemius vs. 88% in her medial gastrocnemius), as well as significant asymmetry in FF in one participant with asymmetric strength and sensation. These results suggest that quantitative water-fat MRI may serve as a biomarker for muscle degeneration which may reveal subclinical changes useful for predicting functional potential and prognosis.
Research in developmental disabilities, 2014 · doi:10.1002/jmri.23998