Optimal graph based segmentation using flow lines with application to airway wall segmentation

This paper introduces a novel optimal graph construction method that is applicable to multi-dimensional, multi-surface segmentation problems. Such problems are often solved by refining an initial coarse surface within the space given by graph columns. Conventional columns are not well suited for surfaces with high curvature or complex shapes but the proposed columns, based on properly generated flow lines, which are non-intersecting, guarantee solutions that do not self-intersect and are better able to handle such surfaces. The method is applied to segment human airway walls in computed tomography images. Comparison with manual annotations on 649 cross-sectional images from 15 different subjects shows significantly smaller contour distances and larger area of overlap than are obtained with recently published graph based methods. Airway abnormality measurements obtained with the method on 480 scan pairs from a lung cancer screening trial are reproducible and correlate significantly with lung function

Automated Labelling Methods For The Extraction Of Liver Region From Magnetic Resonance Images Of Abdomen

The objective of this thesis is to develop a scheme for detecting the region of interest (ROI), namely, liver from the abdomen MR images, which will pave the way in future for the development of an automated diagnostic and analysis system for liver related diseases. Though a large amount of modalities are available in MR imaging, only T2 images are used for the work carried out in this thesis. A general purpose manual labelling tool for defining ROI and two automated schemes for ROI detection of the liver are presented in this thesis

Vessel tree extraction using locally optimal paths

This paper proposes a method to extract vessel trees by continually extending detected branches with locally optimal paths. Our approach uses a cost function from a multiscale vessel enhancement filter. Optimal paths are selected based on rules that take into account the geometric characteristics of the vessel tree. Experiments were performed on 10 low dose chest CT scans for which the pulmonary vessel trees were extracted. The proposed method is shown to extract a better connected vessel tree and extract more of the small peripheral vessels in comparison to applying a threshold on the output of the vessel enhancement filter