Automatic fluid velocity detection methods for digital angiography

Digital angiography is a medical procedure that is used to visualize blood flow. A radioisotope is injected through a catheter that has been maneuvered into the area to be visualized. A sequence of X-ray images is then captured. Digital subtraction is performed between X-ray images captured before and after the dye injection in order to visualize blood flow, without obscuring anatomical structures. Many hemodynamic parameters can now be determined, including blood how velocity. What is lacking in this procedure, however, is a measure by which the method for velocity determination can be verified. Here, the authors present the first step towards verification of automatic flow velocity calculation. They offer an objective comparison of four methods for automatic fluid velocity calculation in which the actual flow velocity is known. They give a concise description of the theory behind and implementation of each method. Finally, the authors discuss the results of applying the four techniques to their experimental data