Mechanical contrast in spectroscopic magnetomotive optical coherence elastography.
The viscoelastic properties of tissues are altered during pathogenesis of numerous diseases and can therefore be a useful indicator of disease status and progression. Several elastography studies have utilized the mechanical frequency response and the resonance frequencies of tissue samples to characterize their mechanical properties. However, using the resonance frequency as a source of mechanical contrast in heterogeneous samples is complicated because it not only depends on the viscoelastic properties but also on the geometry and boundary conditions. In an elastography technique called magnetomotive optical coherence elastography (MM-OCE), the controlled movement of magnetic nanoparticles (MNPs) within the sample is used to obtain the mechanical properties. Previous demonstrations of MM-OCE have typically used point measurements in elastically homogeneous samples assuming a uniform concentration of MNPs. In this study, we evaluate the feasibility of generating MM-OCE elastograms in heterogeneous samples based on a spectroscopic approach which involves measuring the magnetomotive response at different excitation frequencies. Biological tissues and tissue-mimicking phantoms with two elastically distinct regions placed in side-by-side and bilayer configurations were used for the experiments, and finite element method simulations were used to validate the experimental results.
Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, 405 North Mathews Avenue, Urbana IL 61801, USA. Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, 306 North Wright Street, Urbana IL 61801, USA.
Adeel
A
Ahmad
Pin-Chieh
PC
Huang
Nahil A
NA
Sobh
Paritosh
P
Pande
Jongsik
J
Kim
Stephen A
SA
Boppart
D054459:Elasticity Imaging Techniques / Q000379:methods*; D052203:Ferrosoferric Oxide; D060526:Magnetic Fields; D053768:Metal Nanoparticles; D009038:Motion; D013057:Spectrum Analysis / Q000379:methods; D041623:Tomography, Optical Coherence / Q000379:methods*
D052203:Ferrosoferric Oxide