Muscle diffusion tensor imaging in glycogen storage disease V (McArdle disease)

Area of Science:

• Biomedical Imaging
• Musculoskeletal Disorders
• Metabolic Myopathies

Background:

• Glycogen storage disease type V (McArdle disease) is a metabolic myopathy characterized by impaired glycogen metabolism in skeletal muscle.
• Muscle diffusion tensor imaging (mDTI) is a non-invasive technique that can assess muscle microstructure.

Purpose of the Study:

• To investigate differences in diffusion parameters within thigh muscles of patients with McArdle disease compared to healthy controls using mDTI.
• To evaluate the sensitivity of mDTI in detecting intracellular glycogen accumulation in McArdle disease.

Main Methods:

• Prospective study involving 10 McArdle patients and 10 healthy controls.
• 3 Tesla MRI scans including mDTI, T1-weighted, and T2-weighted imaging.
• Analysis of diffusion parameters (eigenvalues, FA, MD) in six thigh muscles; comparison with histochemical analysis of vastus lateralis biopsies from three patients.

Main Results:

• Histochemical analysis confirmed intracellular glycogen accumulation in skeletal muscle fibers of three McArdle patients.
• No statistically significant differences in mDTI parameters were observed between McArdle patients and controls across all evaluated thigh muscles.
• No extracellular histopathological changes were detected.

Conclusions:

• Current mDTI techniques, in their present form, do not show altered diffusion parameters in the thigh muscles of McArdle disease patients.
• The sensitivity of mDTI is insufficient to detect intracellular glycogen accumulation within skeletal muscle fibers in McArdle disease patients.
• Further advancements in mDTI acquisition and processing are needed to potentially detect subtle microstructural changes in metabolic myopathies.