Intravascular ultrasound (IVUS) is an invasive coronary imaging modality which provides insights in the diagnosis and therapy of coronary artery disease. The main advantage of IVUS compared to other coronary imaging techniques such as traditional invasive angiography, is that it allows the tomographic assessment of: the lumen area, the external elastic membrane area, the plaque size, the distribution and the composition of the plaque. It can safely detect and characterize the following types of plaques: necrotic core, fibrous plaque and calcified plaque. One other aspect worth mentioning is that it also provides accurate measurement of the luminal dimensions of the artery of interest. With IVUS, lipid-laden lesions appear hypoechoic, fibromuscular lesions generate low-intensity echoes and fibrous or calcified tissues are echogenic. However, IVUS suffers from a few drawbacks directly connected to its innate image quality. For example, calcium obscures the underlying wall, a phenomenon called acoustic shadowing. One other major image quality issue that emerges from the use of IVUS is the so-called speckle noise, which is the main reason for the grainy texture of IVUS images. This results to poor quality images, which makes their interpretation and processing nontrivial for computed-based diagnostic systems.
Chapter Contents:
- Abstract
- 25.1 Introduction
- 25.2 Background
- 25.2.1 Physical principles of IVUS imaging
- 25.2.2 IVUS acquisition systems
- 25.2.3 IVUS disadvantages (artifacts-problems)
- 25.2.4 IVUS artifacts
- 25.2.4.1 Non-Uniform Rotational Distortion (NURD) and motion artifacts
- 25.2.4.2 Ring-down artifacts
- 25.2.4.3 Guide wire artifacts
- 25.2.4.4 Blood speckles
- 25.2.4.5 Obliquity, eccentricity and vessel curvature problems
- 25.2.4.6 Spatial orientation problem
- 25.3 Speckle noise in IVUS images
- 25.3.1 Model for speckle noise
- 25.3.2 Need for denoising
- 25.3.3 Wavelet transform denoising methods
- 25.3.4 Curvelet transform denoising methods
- 25.4 Segmentation techniques for border identification
- 25.4.1 Edge-tracking and gradient-based techniques
- 25.4.2 Active contour-based techniques
- 25.4.3 Statistical-and probabilistic-based techniques
- 25.4.4 Multiscale expansion-based techniques
- 25.5 Plaque characterization
- 25.5.1 Methodologies developed for plaque characterization using gray-scale IVUS
- 25.5.2 Methodologies developed for plaque characterization using the backscatter IVUS signal
- 25.6 IVUS-based hybrid imaging
- 25.6.1 Fusion of IVUS and coronary angiography
- 25.6.2 Fusion of IVUS and coronary computed tomography
- 25.7 Limitations of IVUS usability
- 25.8 Future perspectives of IVUS
- 25.8.1 Future trends in 3D IVUS reconstruction
- 25.8.2 Future technical development
- 25.9 Conclusions
- References
Inspec keywords:
biomedical ultrasonics;
image texture;
medical image processing;
cardiology;
speckle
Other keywords:
calcified plaque;
plaque size;
IVUS tracking;
external elastic membrane area;
fibrous plaque;
intravascular ultrasound;
grainy texture;
lumen area;
necrotic core;
invasive coronary imaging;
computed-based diagnostic systems;
speckle noise;
artery geometrical features;
plaque type morphology
Subjects:
Patient diagnostic methods and instrumentation;
Optical, image and video signal processing;
Sonic and ultrasonic radiation (biomedical imaging/measurement);
Sonic and ultrasonic applications;
Biology and medical computing;
Computer vision and image processing techniques;
Sonic and ultrasonic radiation (medical uses)