Imaging the Local Nonlinear Viscoelastic Properties of Soft Tissues: Initial Validation and Expected Benefits
| Autor: | Soumya Goswami, Rifat Ahmed, Fan Feng, Siladitya Khan, Marvin M. Doyley, Stephen A. McAleavey |
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| Rok vydání: | 2022 |
| Předmět: | |
| Zdroj: | IEEE Trans Ultrason Ferroelectr Freq Control |
| ISSN: | 1525-8955 0885-3010 |
| Popis: | Imaging tissue mechanical properties has shown promise in non-invasive assessment of numerous pathologies. Researchers have successfully measured many linear tissue mechanical properties in laboratory and clinical settings. Currently, multiple complex mechanical effects such as frequency-dependence, anisotropy and nonlinearity are being investigated separately. However, a concurrent assessment of these complex effects may enable a more complete characterization of tissue biomechanics and offer improved diagnostic sensitivity. In this work we report for the first time a method to map the frequency-dependent nonlinear parameters of soft tissues on a local scale. We recently developed a nonlinear elastography model that combines strain measurements from arbitrary tissue compression with radiation-force based broadband shear wave speed measurements. Here, we extended this model to incorporate local measurements of frequency-dependent shear modulus. This combined approach provides a local frequency dependent nonlinear parameter that can be obtained with arbitrary, clinically realizable tissue compression. Initial assessments using simulations and phantoms validate the accuracy of this approach. We also observed improved contrast in nonlinearity parameter at higher frequencies. Results from ex-vivo liver experiments show 32 dB, 25 dB, dB, 34 dB, and 38 dB higher contrast in elastograms than traditional linear elasticity, elastic nonlinearity, viscosity and strain imaging methods, respectively. A lesion, artificially created by injection of glutaraldehyde into a liver specimen, showed a 59% increase in the frequency dependent nonlinear parameter and 17% increase in contrast ratio. |
| Databáze: | OpenAIRE |
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