Iterative mesh transformation for 3D segmentation of livers with cancers in CT images

Segmentation of diseased liver remains a challenging task in clinical applications due to the high inter-patient variability in liver shapes, sizes and pathologies caused by cancers or other liver diseases. In this paper, we present a multi-resolution mesh segmentation algorithm for 3D segmentation of livers, called iterative mesh transformation that deforms the mesh of a region-of-interest (ROI) in a progressive manner by iterations between mesh transformation and contour optimization. Mesh transformation deforms the 3D mesh based on the deformation transfer model that searches the optimal mesh based on the affine transformation subjected to a set of constraints of targeting vertices. Besides, contour optimization searches the optimal transversal contours of the ROI by applying the dynamic-programming algorithm to the intersection polylines of the 3D mesh on 2D transversal image planes. The initial constraint set for mesh transformation can be defined by a very small number of targeting vertices, namely landmarks, and progressively updated by adding the targeting vertices selected from the optimal transversal contours calculated in contour optimization. This iterative 3D mesh transformation constrained by 2D optimal transversal contours provides an efficient solution to a progressive approximation of the mesh of the targeting ROI. Based on this iterative mesh transformation algorithm, we developed a semi-automated scheme for segmentation of diseased livers with cancers using as little as five user-identified landmarks. The evaluation study demonstrates that this semi-automated liver segmentation scheme can achieve accurate and reliable segmentation results with significant reduction of interaction time and efforts when dealing with diseased liver cases.

Analysis of the perception of institutional function for health sector reform in Nigeria

Institutional function reflects the institution's understanding of the world around it, its ability to locate itself within that world and to make decisions in relation to it. Three dimensions of institutional function were identified as management, environmental mastery and service delivery. This study analysed the perception of institutional function of four hospitals in Nigeria by 507 healthcare professionals and managers and its influence on the implementation of the health sector reform programme in the country. The respondents were doctors and dentists (30%), nurses (27.2%), pharmacists (8.9%), managers (15.5%) and other allied healthcare workers (18.4%). The overall perception of institutional function was 56.3%. The perceptions of the three dimensions of institutional function were management 52.7%, environmental mastery 50.8% and service delivery 62.6%. Three out of 12 statements on institutional function had levels of perception that were lower than 50%. These were adequacy of management skills (49.7%), functioning management information systems that are used in management decision-making (47.9%) and degree of autonomy for the hospitals (42.4%). There is the need to strengthen the institutional function of Nigerian hospitals, especially the acquisition of management skills by the healthcare professionals and managers, management information systems and autonomy for the hospitals.