Statistical Shape Modelling for the Levator Ani

Defective pelvic organ support due to injuries of the levator ani is a common problem in women and its intervention requires a thorough understanding of the structure. Three-dimensional surfaces of the levator ani have proved to be a promising method of studying this. In this paper, we propose to build a statistical shape model (SSM) of the levator ani and describe a segmentation technique based on a limited number of control points with the SSM. The SSM was achieved by the use of harmonic shape embedding with the MDL objective function to optimise parameterisation while segmentation was performed by fitting the model to a user defined set of control points. The value of the technique was demonstrated with data acquired from a group of 11 asymptomatic subjects.Accepted versio

Reproducibility of coronary artery diameter assessments in magnetic resonance coronary angiography: phantom study

This report describes the development of a deformable model for the automatic delineation of coronary artery cross-sectional areas with magnetic resonance imaging. The method is validated with coronary artery phantoms of varying diameters and images with different levels of signal-to-noise ratios. The reproducibility of the technique was examined with simulated geometrical shifts and motions during data acquisition. The experimental results indicate a very high reproducibility and low inter-observers variability of the technique, suggesting its suitability for non-invasive assessment of serial changes of vessel dilatation following pharmacological intervention

Assessment of Mitral Valve Dynamics with 3D Echocardiography

Abstract. This paper describes the use of statistical shape modelling for automatically segmenting mitral valve leaflets from cine 3D transthoracic echocardiographic (TTE) sequences. Principal components analysis was used to determine the dominant modes of variation of the mitral valve leaflets at different phases of the cardiac cycle across subjects. The derived models were subsequently used for automatic segmentation of valve structures through eigen-space optimisation. The clinical potential of the technique was demonstrated by applying the segmented shapes to derive strain distributions over leaflet surfaces due to dynamic morphological changes. A total of 7 healthy volunteers were involved in this study and the accuracy of the technique was assessed through leave-one-out cross-validation. 1

A procedure for semi-automated cadastral boundary feature extraction from high-resolution satellite imagery

Fit-for-purpose land administration aims to align cadastral policies, administration and technology selection with the prevailing societal needs and capacity within a country context. It seeks to support delivery of more rapid and low-cost cadastral boundary mapping – and ultimately more widespread land tenure security. The philosophy suggests that when high positional accuracies are not the primary concern, but when time pressure is, high-resolution satellite images can serve as a source for creating cadastral boundary information. This paper explores the potential of mean-shift segmentation plug-in in QGIS to semi-automatically extract cadastral boundaries in rural areas – based on the land cover information from WorldView-2 satellite images. The segmentation gives a vector file satisfying many cadastral boundary requirements and ready to be used in a GIS environment. The buffer overlay method was used to assess the quality of extracted boundaries. For a non-vegetated terrain having visible boundaries, the approach could be taken as an alternative to support existing, relatively slow, boundary mapping approaches by minimizing the effects of manual digitization and surveying