RESUMO
We propose a navigation-based computer aided diagnosis (CAD) system for the colon. When diagnosing the colon using virtual colonoscopy (VC), a physician makes a diagnosis by navigating (flying-through) the colon. However, the viewpoints and the viewing directions must be changed many times because the colon is a very long and winding organ with many folds. This is a time-consuming task for physicians. We propose a new navigation-based CAD system for the colon providing virtual unfolded (VU) views, which enables physicians to observe a large area of the colonic wall at a glance. This system generates VU, VC, and CT slice views that are perfectly synchronized. Polyp candidates, which are detected automatically, are overlaid on them. We applied the system to abdominal CT images. The experimental results showed that the system effectively generates VU views for observing colon regions.
Assuntos
Algoritmos , Pólipos do Colo/patologia , Colonografia Tomográfica Computadorizada/métodos , Aumento da Imagem/métodos , Interpretação de Imagem Assistida por Computador/métodos , Imageamento Tridimensional/métodos , Software , Desenho Assistido por Computador , Humanos , Modelos Biológicos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Design de SoftwareRESUMO
RATIONALE AND OBJECTIVES: When virtual endoscopy is used as a diagnostic tool, especially as a tool for detecting colon polyps, the user often performs automated fly-through based on automatically generated paths. In the case of automated fly-through in the colon, there are some blind areas at the backs of folds. The aim of this study is to detect undisplayed regions during fly-through and to perform quantitative evaluation. MATERIALS AND METHODS: Undisplayed regions are detected by marking displayed triangles for surface rendering or displayed voxels for volume rendering. The voxels or triangles not having displayed marks are considered to be undisplayed triangles or voxels. Various kinds of automated fly-through paths generated from medial axes of the colon and flattened views of the colon from the viewpoint of the rate of undisplayed regions are evaluated. RESULTS: The experiment results show that about 30% of colon regions are classified as undisplayed regions by the conventional automated fly-through along the medial axis and that the flattened view results in very few undisplayed regions. CONCLUSION: There is a possibility that the automated fly-through methods may cause many undisplayed regions.
