Abstract Details

Title Clinical and Imaging Biomarkers in Myotonic Dystrophy Type 2

Topic Neuromuscular and Clinical Neurophysiology (EMG)

Presentation(s) P2 - Poster Session 2 (8:00 AM-9:00 AM)

Poster/Presentation
Number 11-022

Objective This study aims to characterize the imaging phenotype and utility of imaging biomarkers in DM2 using artificial intelligence-based (AI) muscle segmentation algorithms to analyze whole-body MRI scans.

Background Myotonic Dystrophy Type 2 (DM2) is an adult-onset genetic condition characterized by myotonia, proximal muscle weakness and wasting, pain, and multi-systemic features. DM2 causes muscle degeneration resulting in the replacement of muscle by adipose tissue and fibrosis. The distribution of weakness in DM2 is distinct from that seen in other muscular dystrophies. Therefore, understanding the relationship of both muscle fat fraction (MFF) and contractile volume (CV) with physical functioning of DM2 patients is essential for understanding progression in DM2.

Design/Methods We performed a cross-sectional study to document the relationship between MRI-based muscle measurements and clinical endpoints in patients with genetically confirmed DM2. Each patient was evaluated by a neurologist to assess their strength, physical function, and patient reported outcomes. We utilized AI-based muscle segmentation to calculate MFF and CV in 38 muscles bilaterally from whole-body Dixon MRI scans.

Results This cohort included 6 females and 6 males with a mean age of 52.5±15.4 years and mean disease duration of 12.5±7.8 years. The gluteus maximus and erector spinae muscles had the highest average MFF. Mean MFF in fully captured muscles ranged from 36.5-7.4%. Higher MFF was associated with shorter 6-minute walk distance (ρ=-0.65, p-value=0.02) and slower 10 m walk/run (ρ=0.74, p-value=0.01). Higher CV was associated with longer 6-minute walk distance (ρ=0.63, p-value=0.03) and faster 10 m walk/run (ρ=-0.73, p-value=0.01).

Conclusions This study is the first to use whole body MRI to characterize muscle involvement in DM2. The results identify a pattern of proximal muscle involvement in DM2 and an association between higher MFF and diminished physical performance. Larger, longitudinal studies are needed to validate the utility of imaging biomarkers in DM2.

Authors/Disclosures
Lauren Hinkley PRESENTER	Miss Hinkley has nothing to disclose.
Kathryn R. Wagner, MD, PhD (The Kennedy Krieger Institute)	Dr. Wagner has received personal compensation for serving as an employee of F. Hoffmann-La Roche Ltd. Dr. Wagner has stock in F. Hoffmann-La Roche.
Michael A. Jacobs (University of Texas- Houston)	Michael A. Jacobs has received intellectual property interests from a discovery or technology relating to health care.
Doris G. Leung, MD (Kennedy Krieger Institute)	The institution of Dr. Leung has received research support from US Department of Defense. The institution of Dr. Leung has received research support from Fulcrum Therapeutics. The institution of Dr. Leung has received research support from ML Bio Solutions, Inc.. The institution of Dr. Leung has received research support from Sarepta Therapeutics. The institution of Dr. Leung has received research support from Cumberland Pharmaceuticals. The institution of Dr. Leung has received research support from FibroGen Inc.. The institution of Dr. Leung has received research support from Astellas Pharma. The institution of Dr. Leung has received research support from University of Kansas Medical Center Research Institute. The institution of Dr. Leung has received research support from Pfizer, Inc.. The institution of Dr. Leung has received research support from Harmony Biosciences. The institution of Dr. Leung has received research support from Edgewise Therapeutics. The institution of Dr. Leung has received research support from F. Hoffmann-La Roche AG. The institution of Dr. Leung has received research support from Asklepios BioPharmaceutical, Inc.. The institution of Dr. Leung has received research support from Avidity Biosciences. The institution of Dr. Leung has received research support from Virginia Commonwealth University. The institution of Dr. Leung has received research support from Seattle Children's Hospital.

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