| Autor: |
Véronique Miette, Cécile Bastard, Jean-Marc Perarnau, Frédéric Patat, Jean-Pierre Remenieras |
| Rok vydání: |
2015 |
| Předmět: |
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| Zdroj: |
2015 IEEE International Ultrasonics Symposium (IUS). |
| DOI: |
10.1109/ultsym.2015.0474 |
| Popis: |
Steatosis is an accumulation of fat in the liver. A definitive diagnosis can only be achieved by liver biopsy and histopathological analysis. Ultrasound imaging shows a hyperechogenic bright image and has some diagnostic accuracy in detecting steatosis but is not good at distinguishing NASH and fibrosis within NAFLD. Magnetic Resonance Imaging can also be used to quantify fatty infiltration (T1-weighted gradient-echo in-and out-phase) with good performances. The objective of this work is to evaluate the feasibility of fatty liver quantification using vibration-controlled transient elastography (VCTE). We have developed a method to estimate the shear celerity dispersion c s (w) robust in vivo based on an new inverse problem algorithm. The ultrafast recording (9.8KHz) of the shear wave propagation induced in the liver by the Fibroscan is compared to an analytical model of the transient axial tissue strain rate ∂V z (z,w)/∂z in the Space/Frequency domain. This model is derived using the elastodynamic Green function who takes into account the strong diffraction effect in the near field of a radiator and extra attenuation due to viscosity. Shear wave dispersion curves in 20Hz–100Hz bandwidth are fitted by the Voigt model for shear elastic modulus µ and shear viscosity η estimation. Initial clinical validation was carried out on two patients with different percentage of fat in the liver measured using MRI. For the patient with 2% of fat, we obtained a shear elastic modulus µ=1.6±0.1kPa and a shear viscosity η=1.4±0.3Pa.s. For the second patient with 22% of fat, we obtained µ=1.1±0.1kPa and η=2.3±0.4Pa.s. This paper demonstrates the in vivo ability of our Shear Wave Spectroscopy method to quantify both shear elasticity and shear viscosity who showed to be sensitive in characterizing the mechanical properties of fatty acid. Additional clinical validations are in progress on 50 volunteers and 25 patients with different steatosis grades at Tours Hospital using biopsy as reference. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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