Accelerated 4D phase contrast MRI in skeletal muscle contraction

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Musculoskeletal Research

Background:

• Three-dimensional (3D) time-resolved (4D) phase contrast MRI is valuable for studying muscle contraction.
• Conventional 4D MRI requires lengthy scan times due to interleaved acquisitions for adequate spatiotemporal resolution.
• Accelerated techniques are needed to improve efficiency in dynamic musculoskeletal MRI.

Purpose of the Study:

• To develop and evaluate a compressed sensing accelerated 4D phase contrast MRI technique.
• To quantify muscle velocities and strain rates in the lower leg during dynamic plantarflexion/dorsiflexion.
• To assess the impact of acceleration on quantitative MRI measurements of muscle function.

Main Methods:

• Employed compressed sensing with Cartesian Poisson disk undersampling (factors 3.14X to 6.41X) in nine healthy volunteers.
• Acquired 4D phase contrast MRI data during active plantarflexion/dorsiflexion tasks.
• Reconstructed undersampled data and quantified velocity and strain rate in key lower leg muscles (gastrocnemius, tibialis anterior, soleus).

Main Results:

• No significant differences in muscle velocity values were found across varying acceleration factors.
• Strain rate analysis consistently yielded two non-zero eigenvalues (s+, s-) and one zero eigenvalue (s3).
• Strain rate eigenvalues remained consistent regardless of the acceleration factor used.

Conclusions:

• Compressed sensing reconstruction of undersampled 4D phase contrast MRI provides quantitative muscle velocity and strain rate data comparable to reference scans.
• This accelerated approach allows for time-resolved 3D imaging with reduced scan times.
• The method holds potential for future investigations into the relationship between muscle architecture and function.