Physical priors in virtual colonoscopy

Hassan Rivaz, Yoshihisa Shinagawa, Jianming Liang

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

    1 Scopus citations


    Electronic colon cleansing (ECC) aims to remove the contrast agent from the CT abdominal images so that a virtual model of the colon can be constructed. Virtual colonoscopy requires either liquid or solid preparation of the colon before CT imaging. This paper has two parts to address ECC in both preparation methods. In the first part, meniscus removal in the liquid preparation is studied. The meniscus is the curve seen at the top of a liquid in response to its container. Left on the colon wall, the meniscus can decrease the sensitivity and specificity of virtual colonoscopy. We state the differential equation that governs the profile of the meniscus and propose an algorithm for calculating the boundary of the contrast agent. We compute the surface tension of the liquid-colon wall contact using in-vivo CT data. Our results show that the surface tension can be estimated with an acceptable degree of uncertainty. Such an estimate, along with the meniscus profile differential equation will be used as an a priori knowledge to aid meniscus segmentation. In the second part, we study ECC in solid preparation of colon. Since the colon is pressurized with air before acquisition of the CT images, a prior on the shape of the colon wall can be obtained. We present such prior and investigate it using patient data. We show the shape prior is held in certain parts of the colon and propose a method that uses this prior to ease pseudoenhancement correction.

    Original languageEnglish (US)
    Title of host publicationMedical Imaging 2009
    Subtitle of host publicationComputer-Aided Diagnosis
    StatePublished - 2009
    EventMedical Imaging 2009: Computer-Aided Diagnosis - Lake Buena Vista, FL, United States
    Duration: Feb 10 2009Feb 12 2009

    Publication series

    NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
    ISSN (Print)1605-7422


    OtherMedical Imaging 2009: Computer-Aided Diagnosis
    Country/TerritoryUnited States
    CityLake Buena Vista, FL


    • CT colonography
    • Electronic colon cleansing
    • Meniscus
    • Unprepared colon
    • Virtual colonoscopy

    ASJC Scopus subject areas

    • Electronic, Optical and Magnetic Materials
    • Biomaterials
    • Atomic and Molecular Physics, and Optics
    • Radiology Nuclear Medicine and imaging


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