Diffusion tensor imaging of the human calf: Variation of inter- and intramuscle-specific diffusion parameters

Area of Science:

• Biomedical Engineering
• Radiology
• Human Anatomy

Background:

• Diffusion Tensor Imaging (DTI) and fiber tractography are advanced MRI techniques.
• Understanding variations in diffusion parameters is crucial for accurate muscle analysis.
• Calf muscle anatomy presents complex inter- and intramuscular structures.

Purpose of the Study:

• To determine how age, gender, muscle location, and BMI affect diffusion parameters in human calf muscles.
• To investigate inter- and intramuscular variations in calf muscle diffusion characteristics.
• To establish normative DTI values for calf muscles in young adults.

Main Methods:

• 18 healthy volunteers (20-35 years) underwent 3T MRI with a 16-channel Torso XL coil.
• Fiber tractography and DTI analysis were performed on whole calf muscles and segmented along the z-axis.
• Fractional anisotropy (FA) and mean diffusivity (MD) were calculated for each muscle and segment.

Main Results:

• Significant gender-based differences in FA were observed for tibialis anterior (AT) and extensor digitorum longus (EDL) muscles.
• Substantial intramuscular variations in diffusion parameters were found between adjacent muscle segments.
• Muscle insertions exhibited higher diffusion parameter variability than muscle bellies; no correlation with age or BMI.

Conclusions:

• Calf muscle diffusion parameters show significant inter- and intramuscular variability, influenced by gender but not age or BMI in young adults.
• When analyzing DTI data, distinctions between muscle bellies and insertions are essential.
• These findings aid in the precise interpretation of DTI-based muscle studies.