Paraspinal muscle architecture in adolescent girls: A diffusion tensor imaging study

Area of Science:

• Biomechanics
• Developmental Biology
• Medical Imaging

Background:

• Skeletal development is influenced by forces from paraspinal muscles.
• Understanding paraspinal muscle architecture is vital for diagnosing and treating spinal disorders.
• Current methods for assessing muscle architecture are often invasive.

Purpose of the Study:

• To develop a non-invasive method for quantifying in-vivo paraspinal muscle architecture.
• To analyze fascicle orientation, length, and curvature in adolescent multifidus and longissimus muscles.
• To investigate side-to-side and regional variations in paraspinal muscle architecture.

Main Methods:

• T1-weighted and diffusion-tensor MRI scans were performed on 16 female adolescents.
• Anatomically constrained fiber tractography was used to reconstruct muscle fascicles from T5-L2.
• Muscle fascicle orientation angle, length, and curvature were quantified using statistical models.

Main Results:

• Significant regional variations in fascicle orientation angles were observed for both multifidus and longissimus muscles.
• A negative correlation was found between fascicle length and orientation angle.
• Multifidus muscles exhibited greater fascicle curvature than longissimus muscles, forming 'S'-shaped fascicles.

Conclusions:

• A novel, non-invasive MRI-based method was established to quantify paraspinal muscle architecture in vivo.
• Significant side-to-side and regional variations in fascicle architecture exist in typically developing adolescent spines.
• These findings provide a foundation for understanding spinal biomechanics and diagnosing developmental spinal disorders.