Model-based elastography: a survey of approaches to the inverse elasticity problem

Area of Science:

• Biomedical Imaging
• Biophysics
• Medical Physics

Background:

• Elastography is an emerging imaging technique.
• It distinguishes normal from diseased tissues using biomechanical properties.
• Current methods include quasi-static, harmonic, and transient elastography.

Purpose of the Study:

• To review current elastography approaches.
• To describe inversion schemes for elastographic imaging.
• To document efforts in developing elastography as an inverse problem.

Main Methods:

• Review of quasi-static, harmonic, and transient elastography.
• Description of inversion schemes: first-order approximation, direct and iterative methods for linear elastic, isotropic materials.
• Discussion of advanced reconstruction methods for complex mechanical behavior.

Main Results:

• Elastography aims to provide reliable shear modulus estimates.
• Various inversion schemes are employed to reconstruct mechanical parameters.
• Challenges include transforming ill-posed problems, improving forward models for soft tissues, and developing robust evaluation procedures.

Conclusions:

• Model-based elastography requires addressing key issues for broader adoption.
• Reliable estimation of mechanical parameters is crucial for clinical application.
• Further development is needed in problem formulation, modeling, and validation.