The Hong Kong University of Science and Technology
Department of Computer Science


PhD Thesis Defence


"Segmentation Algorithms for Quantitative Analysis of Vascular
Abnormalities on Three Dimensional Angiography"

By

Mr. Chun Kit Wong


Abstract

Cerebrovascular disease, in particular intracranial atherosclerotic
stenosis and cerebral aneurysm, is a common cause of stroke, which is the
third leading cause of death in many places including Hong Kong.
Understanding the geometric characteristics of those lesions is an
essential part of diagnosis and endovascular treatment planning. In the
clinical environment, quantitation of the lesions is often conducted on
2-D digital subtraction angiography (DSA). The quantitation may suffer
from the foreshortening effect due to inappropriate X-ray projection angle
selection and the non-linear magnification caused by the perspective
projection. The technological advances in 3-D medical imaging open up new
opportunities for the elucidation of the lesion characteristics. This
motivates us to develop three novel algorithms for the segmentation of
vessels and vascular lesions in 3-D angiography.

The first and the second algorithms are low-level segmentation algorithms
aiming at producing angiographic segmentation for the third algorithm to
perform high-level segmentation of the atherosclerotic plaque volume and
aneurysm body from the diseased portion of the arteries. Such an approach
enables later interactive or automatic quantitative analyses on the
pathological structures. In an in vivo study with nearly twenty
angiograms, the results show that our method can help increase the
measurement repeatability of the clinical parameters by more than ten
times. Therefore, we believe that the works presented can help elucidate
the lesion characteristics for diagnosis of the cerebrovascular diseases
and endovascular treatment planning. Lastly, the direction of future
studies is discussed in this dissertation.


Date:			Tuesday, 22 August 2006

Time:			10:00a.m.-12:00noon

Venue:			Room 5501
			Lifts 25-26

Chairman:		Prof. Guochang Zhang (ACCT)

Committee Members:	Prof. Albert Chung (Supervisor)
			Prof. Huamin Qu
			Prof. Chi Keung Tang
			Prof. Pengcheng Shi (ECE)
			Prof. Pheng Ann Heng (Comp. Sci. & Engg., CUHK)


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