P121 Long-term follow-up study of muscle MRI in myotonic dystrophy type 1: correlations with demographic and clinical characteristics

• Published in: Neuromuscular disorders : NMD 2023-10, Vol.33, p.S77-S78
• Main Authors: Fionda, L., Lauletta, A., Tufano, L., Bucci, E., Antonini, G., Garibaldi, M.
• Format: Article
• Language: English
• ISSN: 0960-8966; 1873-2364
• DOI: 10.1016/j.nmd.2023.07.056

Muscle MRI is a useful biomarker of disease activity and severity in neuromuscular disorders. In the gene-therapy era, objective evaluation of natural history of progressive diseases and their correlations with clinical evolution are warranted. Herein, we report on long-term longitudinal study of muscle MRI in 29 patients affected by Myotonic Dystrophy type 1 (DM1). Twenty-nine consecutive patients with genetically confirmed DM1 were included in this prospective, longitudinal study. Each patient underwent a complete neurologic examination including Muscular Impairment Rating Scale (MIRS) and an MRI study at baseline and at follow-up. Demographic and genetic characteristics of each patient were recorded. We analyzed 32 couple of muscles of lower body (LB) and 16 couple of muscles of upper body (UB) by T1 and STIR sequences. T1-, STIR-, and atrophy-scores and their variations between MRIs were considered. Correlations between different MRI-sequences data and between MRI and demographic, clinical and genetic characteristics were analyzed. The median FU was 3 years (range 21-53 months). The average T1-score progression was +3.1% in LB (range 0-10.6%) and +0.8% in UB (range 0-4.2%). Patients with higher T1-score variation at FU showed an increase of MIRS rating at FU. Twenty-five % of patients did not show any progression in T1-score at FU regardless of disease severity and T1-score at baseline and time lapse between MRIs. Some patients with normal MRI study at baseline (T1 negative/STIR negative) showed STIR positivity in some muscles at FU (3.1-4.7%) and a minimal T1-score progression at FU (+0.3-0.6%) in certain of the STIR positive muscles. Muscle atrophy showed a progression regardless T1-score and STIR positivity or their progression at FU. Muscle MRI is a sensitive biomarker to assess disease activity and progression in DM1.