thesis
Image and Signal Processing in Intravascular Ultrasound
- Publication date
- 27 June 1997
- Publisher
- Intravascular ultrasound (rvUS) is a new imaging mOdality providing real-time, crosssectional,
high-resolution images of the arterial lumen and vessel wall. In contrast to
conventional x-ray angiography that only displays silhouette views of the vessel lumen,
IVUS imaging permits visualization of lesion morphology and accurate measurements
of arterial cross-sectional dimensions in patients. These unique capabilities have led to
many important clinical applications including quantitative assessment of the severity,
restenosis, progression of atherosclerosis, selection and guidance of catheterbased
therapeutic procedures and short- and long-term evaluation of the outcome of an
intravascular intervention.
Like the progress of other medial imaging modalities, the advent of IVUS techniques
has brought in new challenges in the field of signal and image processing. Quantitative
analysis of IVUS images requires the identification of arterial structures such as the
lumen and plaque within an image. Manual contour tracing is well known to be time
consuming and subjective. Development of an automated contour detection method
may improve the reproducibility of quantitative IVUS and avoid a tedious manual
procedure. Computerized three-dimensional (3D) reconstruction of an IVUS image
series may extend the tomographic data to a more powerful volumetric assessment of
the vessel segment. Obviously, this could not be achieved without the advance of 3D
image processing techniques. Furthermore, it is demonstrated that processing of the
original radio frequency (RF) echo signals provides an efficient means to improve the
IVUS image quality as well as a new approach to extract volumetric flow information.
The goals of the studies reported in this thesis are therefore directed toward
development of video image and RF signal processing techniques for image
enhancement, automated contour detection, 3D reconstruction and flow imaging.
In this chapter several IVUS scanning mechanisms and some background information
about ultrasonic imaging are briefly introduced. The principles of different video-based
contour detection approaches and examples of contour detection in echocardiograms
are discussed. Subsequently, applications of RF analysis in IVUS images are reviewed,
followed by the scope of this thesis in the final part.