A two-dimensional (2D) systems biology-based discrete liver tissue model: A simulation study with implications for ultrasound elastography of liver fibrosis
Authored by Yu Wang, Jingfeng Jiang
Date Published: 2019
United States National Institutes of Health (NIH)
Model Code URLs:
Model code not found
Continuum tissue models that were often used to simulate or analyze the
mechanical properties of tissues being imaged may not be biologically
realistic. Our primary objective was to establish the feasibility of
using systems biology to construct biologically relevant tissue models
linking tissue structure, composition and architecture to the ultrasound
measurements directly. The first application was designated to model
fibrotic liver tissues.
The proposed liver tissue model leveraged established histopathology
knowledge of fibrotic liver tissues. Particularly, rules of systems
biology derived from molecular histopathology were first implemented
into an agent-based software platform SPARK to reflect progressions of
liver fibrosis with/without steatosis. Then, microscopic compositions of
tissues (e.g. cellular components) were converted to computing grids (at
the 50-100 mu m scale) for wave simulations using an open-source K-Wave.
To verify the physical soundness of the proposed model, virtual wave
speed measurements (i.e. shear wave speed [SWS] and the speed of sound
[SOS]) were performed.
Our initial results demonstrated that the simulated SWS values increased
with the progression of liver fibrosis (from 1.5 m/s [Fibrosis stage
1] to 4 m/s [Fibrosis stage 4]). Similarly, the simulated SOS values
were within the range of clinical data (from 1575 m/s [Fibrosis stage
0-3] to 1594 m/s [Fibrosis stage 4]).
In summary, we found that those systems biology simulated fibrotic liver
tissues with and without steatosis can reflect spatial characteristics
of relevant histology. Also, their mechanical characteristics (i.e.
shear/compressional wave speed) were in good agreement with data
reported in the clinical literature.
Acoustic radiation force
Ultrasound tissue characterization