Biomedical Engineering Reference
In-Depth Information
1.7 Conclusions
Although IVUS is continuously gaining in use in practice due to its multiple
clinical advantages, the technical process of IVUS image generation is not known
to doctors and researchers developing IVUS image analysis. This fact leads to
a simplified use, analysis, and interpretation of IVUS images based only on the
gray-level values of image pixels.
In this chapter we discuss a basic physical model to generate synthetic 2D
IVUS images. The model has different utilities: Firstly, an expert can generate
simulated IVUS images in order to observe different arterial structures of clinical
interest and their gray-level distribution in real images. Secondly, researchers
and doctors can use our model to learn and to compare the influence of different
physical parameters in the IVUS image formation, such as the ultrasound fre-
quency, the attenuation coefficient, the beam number influence, and the artifact
generations. Thirdly, this model can generate a large database of synthetic data
under different device and acquisition parameters to be used for validating the
robustness of image processing techniques. The IVUS image generation model
provides a basic methodology that allows us to observe the most important
real image emulation aspects. This initial phase does not compare pixel to pixel
values generation, showing the coincidence with the real image, but looks for a
global comparison method based on gray-level difference distribution. The input
model applies standard parameters that have been extracted from the literature.
Hence this model is generic in the sense that the model allows simulation of dif-
ferent processes, parameters, and makes it possible to compare to real data and
to justify the generated data from the technical point of view.
The model is based on the interaction of the ultrasound waves with a discrete
scatterer distribution of the main arterial structures. The obtained results of the
validation of our model illustrate a good approximation to the image formation
process. The 2D IVUS images show a good correspondence between the arte-
rial structures that generate the image structures and their gray-level values. The
simulations of the regions and tissue transitions of interest lumen, lumen/intima,
intima/media, media/adventitia and adventitia, have been achieved to a satisfac-
tory degree. Interested readers are invited to check the generation model in
http://www.cvc.uab.es/
∼
misael.
