A computational approach to calculate personalized pennation angle based on MRI: effect on motion analysis

Area of Science:

• Biomechanics
• Musculoskeletal modeling
• Medical imaging

Background:

• Muscle architecture, including pennation angle, dictates force production and movement.
• Accurate musculoskeletal models are crucial for understanding human locomotion and posture.
• Existing models often use generic parameters, potentially limiting individual-specific analysis.

Purpose of the Study:

• To develop and evaluate a computational method for calculating subject-specific pennation angles from MRI-based 3D models.
• To assess the impact of subject-specific pennation angles on motion analysis using personalized musculoskeletal models.
• To investigate interindividual variations in pennation angles within the quadriceps femoris group.

Main Methods:

• A 3D method was developed to compute pennation angles from MRI data.
• Automated fiber orientation computation and centroid-based line of action determination were employed.
• Neuromuscular simulations (OpenSim) analyzed gait and deep squat in three healthy males, comparing generic and personalized models.

Main Results:

• Significant interindividual variations in pennation angles were observed, particularly for vastus intermedius and vastus medialis.
• Subject-specific pennation angles led to notable differences in muscle moments and forces compared to generic models.
• Personalized models demonstrated substantial variations in dynamic motion analysis outcomes.

Conclusions:

• A novel MRI-based approach for determining subject-specific pennation angles was successfully developed and validated.
• Personalized pennation angle modeling provides greater individual detail in motion analysis.
• This approach enhances the understanding of specific subject motion behaviors by accounting for unique muscle architecture.