Quantifying deformations and strains in human intervertebral discs using Digital Volume Correlation combined with MRI...

Area of Science:

• Biomedical Engineering
• Radiology
• Orthopedics

Background:

• Intervertebral disc (IVD) degeneration causes low back pain, affecting 75% of the population.
• Understanding internal IVD mechanical changes is crucial for developing effective treatments.
• Digital Volume Correlation (DVC) is a technique for measuring strain by tracking patterns in volumetric images.

Purpose of the Study:

• To quantify strain and deformation errors of DVC-MRI in human IVDs.
• To establish the optimal DVC methodology and settings for IVD analysis.
• To assess the non-invasive measurement of internal IVD strains.

Main Methods:

• Eight human lumbar IVDs were scanned using 9.4 T MRI.
• A 'zero-strain study' quantified system noise, followed by a loaded study with 2 mm axial compression.
• Three DVC methods (FFT, DC, FFT+DC) were compared using varying subset sizes (8-88 voxels).

Main Results:

• The FFT + DC DVC methodology with a 56-voxel subset size (2520 µm) was optimal.
• Displacement errors were below 28 µm, and strain errors did not exceed 3000 microstrain.
• The chosen method demonstrated a balance between accuracy and spatial resolution.

Conclusions:

• DVC-MRI can accurately and non-invasively quantify internal strains within human IVDs.
• This technique holds significant potential for clinical assessment of IVD health and mechanical behavior.
• The findings pave the way for improved diagnostics and therapeutic strategies for low back pain.