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Title Estimation of blood velocities with ultrasound
Author Lacasa, Isobel Rodíguez
Supervisor Jensen, Jørgen Arendt (Biomedical Engineering, Department of Electrical Engineering, Technical University of Denmark, DTU, DK-2800 Kgs. Lyngby, Denmark)
Institution Technical University of Denmark, DTU, DK-2800 Kgs. Lyngby, Denmark
Thesis level Master's thesis
Year 1999
Abstract The measurement of blood flow is essential in the diagnosis of most vascular diseases. Modern ultrasound scanners find only the axial velocity of blood i.e. the velocity component parallel to the ultrasound beam. Therefore, when estimating the blood flow rate, physicians need to emit hypothesis. They have to estimate the angle, between the vessel studied and the ultrasound beam, and to estimate whether the flow is steady or disturbed. This proves that the measurement of the complete velocity vector will be of great interest since flow reconstruction will become an objective measure. The work developed in this thesis was focussed on finding a scanning method which allows the estimation of the transverse component of blood velocity. The point of departure was a work developed by Bonnefus [1] ten years ago. This work suggests the use of multiple parallel beams in reception for each pulse emission, and a cross-correlation estimation method for finding the transverse velocity component. A new approach was then developed. This was the calculation of a transverse beam that track the transverse motion of blood flow. Simulations were made that gave satisfactory results in the case of a blunt velocity profile. The idea of a lateral beam was then extended to several beams in the direction of blood flow. Satisfactory results were then obtained for parabolic profiles. The angle is again to be set by physicians, but the result is the complete velocity vector estimation.
Pages 105
Admin Creation date: 2009-06-25    Update date: 2009-06-25    Source: dtu    ID: 245554    Original MXD