From supersonic shear wave imaging to full-field optical coherence shear wave elastography

Area of Science:

• Biomedical Optics
• Medical Imaging
• Biophysics

Background:

• Elasticity mapping offers complementary contrast to ultrasonic imaging for tissue diagnosis.
• Optical coherence tomography (OCT) provides endogenous contrast but lacks elasticity information.
• Current static elastography coupled with OCT has limitations in stiffness quantification.

Purpose of the Study:

• To combine transient elastography with full-field OCT (FF-OCT) for microscopic elasticity mapping.
• To improve OCT-based diagnosis by adding complementary elasticity contrast at the microscopic scale.
• To assess the feasibility and sensitivity of this combined approach for tissue stiffness evaluation.

Main Methods:

• Integration of transient elastography using ultrasonic radiation forces with FF-OCT.
• Utilizing an ultrafast ultrasonic scanner and an ultrafast camera (10,000-30,000 images/s) to track shear wave propagation.
• Comparison of FF-OCT sensitivity to shear vibrations against ultrafast ultrasound.

Main Results:

• The combined FF-OCT and transient elastography system successfully tracked shear wave propagation.
• FF-OCT demonstrated significantly higher sensitivity to minute shear vibrations (nanometer to micrometer scale) compared to ultrafast ultrasound.
• Stiffness measurements in gel phantoms and ex vivo rat brain showed good agreement between FF-OCT and ultrasound shear wave elastography.

Conclusions:

• The combination of transient elastography and FF-OCT enables high-resolution, sensitive elasticity mapping at the microscopic level.
• This technique offers enhanced diagnostic potential for OCT by providing quantitative stiffness information.
• The findings suggest FF-OCT is a promising modality for advanced biomechanical tissue characterization.