Twelve‐month change in quantitative MRI calf muscle fat fraction in CMT1A predicts clinical change over 4 years
Abstract Objective We measured clinical and quantitative MRI outcome measures in CMT1A to assess long‐term responsiveness, establish longitudinal validity and assess MRI as a bridging biomarker. Methods Twenty patients with CMT1A and 20 matched controls underwent MRI, myometry and clinical assessmen...
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| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Wiley
2025-04-01
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| Series: | Annals of Clinical and Translational Neurology |
| Online Access: | https://doi.org/10.1002/acn3.52314 |
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| Summary: | Abstract Objective We measured clinical and quantitative MRI outcome measures in CMT1A to assess long‐term responsiveness, establish longitudinal validity and assess MRI as a bridging biomarker. Methods Twenty patients with CMT1A and 20 matched controls underwent MRI, myometry and clinical assessments up to four times over mean 4‐year follow‐up. Bilateral calf muscle MRI included T1‐weighted sequences with Mercuri grading and three‐point Dixon quantitative fat fraction assessment. Patients were grouped on baseline calf muscle fat fraction: normal <5%, intermediate 5%–70% and end stage >70%. Results Controls showed no significant change on MRI. CMT1A patients' calf muscle fat percentage progressed across all follow‐up visits: mean absolute change was +1.3 ± 1.2% (mean ± SD) at 12 months, +2.3 ± 2.2% at 27 months and 2.8 ± 2.9% at 49 months. Mercuri grades increased by 0.07 ± 0.11 per year. Responsiveness of individual muscle fat was less than for both calves combined. Patients with intermediate baseline calf muscle fat showed greater progression of 3.7 ± 2.3% at 27 months. There was strong correlation between rate of progression of calf muscle fat and CMT Examination Score (ρ = 0.71, P = 0.005). Calf muscle fat progression at 12 months correlated significantly with annualised CMT Examination Score progression at final visit (ρ = 0.65, P = 0.01). Interpretation We demonstrated a consistent progression of calf muscle MRI fat over 4 years, significant longitudinal correlation between CMT Examination Score and calf muscle fat, and potential as a bridging biomarker by 1 year change in fat correlating with long‐term clinical progression. Increasing study duration minimally increased responsiveness; however, selecting patients with intermediate fat fraction significantly increased responsiveness. |
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| ISSN: | 2328-9503 |