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Improved interface for deep venous thrombosis screening using B-mode ultrasound

University of British Columbia

This work presents a system for the screening of deep venous thrombosis by processing B-mode ultrasound images, and by using information from additional force-torque and location sensors. It is known that deep venous thrombosis (DVT) is a disease that affects the venous system, where blood clots are formed and obstruct the venous pathways, causing serious consequences such as pulmonary embolism. Identifying DVT using conventional ultrasound principally relies on identifying incompressible veins which contain clots by using the B-mode imaging modality to view vessels in a transverse plane. A model-based contour detection method is presented which assumes that the transverse section of a vein can be described by an ellipse. By using the image brightness values a modified Star-Kalman filter is used to detect the vessel contour, and a validation scheme is implemented in order to accept or reject the detected curve. Additional information from a six degree-of-freedom force-torque sensor and a six degree-of-freedom location sensor allow the ultrasound image and detected contour to be placed in a three-dimensional virtual environment, were they are displayed in correct perspective. By stitching together several detected contours, a three-dimensional model of the examined vessel can be constructed and displayed. The force-torque information is combined with the vessel area obtained via the contour detection method, and an objective compression assessment can be obtained for the examined vessel segment. By repeating this procedure, a complete vessel can be screened for DVT, with an objective measure as a result. Additionally, this information can be mapped to the previously constructed virtual model.

Thesis/Dissertation

application/pdf

2009-10-17

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http://hdl.handle.net/2429/14004

Electrical and Computer Engineering

University of British Columbia

UBCV

DSpace