Computer assisted detection and modelling of paediatric airway pathology from medical images

Benjamin Irving

5 September 2012

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Clinical motivation

cross section
  • TB still has a considerable effect of quality of life in developing countries
  • Incidence of TB in South Africa 981 per 100 000 / year
  • Especially difficult to detect in children
  • Need for additional methods of detection
  • Lymphadenopathy is commonly present in paediatric tuberculosis
    • ≈ 90% - 100% of patients under 5 years
  • Affects the airway
  • Additional tests based on analysis of airway deformation


Thesis outline

Airway segmentation

Coronal CT slice showing segmented airway regions

cross section

Morphological filtering a) region of an axial slice b) segmentation after coronal and sagittal filtering c) segmentation after axial filtering

Segmentation (Interactive Figure)

Mesh representation of airway segmentation

Click and drag figure to rotate. Scroll to zoom.

Click on figure and press 'm' to toggle mesh views.

Structure and skeletonisation

Airway segmentation and labelled skeleton. Colours are used to distinguish branches in the skeleton and a background CT slice is provided to demonstrate position



Generating surface landmarks in the region of interest on the airway surface

Registration (Interactive Figure)

Registration of a template mesh to each airway region using thin-plate-spline and closest point alignment

Slider for each transform

Move each slider to the right to perform template warp

Click and drag figure to rotate. Scroll to zoom.

Obstruction detection

Detecting and segmenting beyond points of obstruction

Classification of airway pathology (Interactive)

A single PCA mode of variation for the airway dataset

PCA mode 1
(+ λ → 0 → - λ)

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Move the slider to show the variation along one statistical mode

Classification of airway pathology

A number of modes of variation are used to train a classifier to detect airway pathology

Classification of airway pathology

ROC curves for classification of paediatric TB from airway shape deformation

Projection of 3D model onto 2D surface

Projection of silhouette edge vertices onto a 2D surface.

Used to assist in the segmentatio of the airways in 2D radiographs


Contributions and achievments