Blood flow rate is an important parameter for functional evaluation of vascular disease. Instantaneous blood flow measurements from digital cerebral angiograms can be performed during endovascular interventional procedures providing radiologists with real-time minimally invasive flow measurements. Most published videodensitometric techniques assume a specific radial profile of velocity. Such assumptions can cause errors if the velocity profile differs from the model, changes during the heart cycle or if contrast concentration is not radially uniform. All of these conditions are typical in clinical practice. We propose to divide the vessel inside the region of interest into a number of narrow laminae and its X-ray image into corresponding narrow bands. Flow inside each lamina is assumed to be plug and parallel to the lamina. Blood flow velocities within each band are be computed using existing angiographic techniques and are used to compute flow velocities within each laminae and within the entire vessel. We evaluated the new approach on simulated and phantom angiograms. It improved accuracy of measurements of plug-flow algorithms from simulated angiograms. The results obtained during the evaluation of the technique on phantom angiograms are inconclusive. The proposed algorithm extends regular videodensitometric flow measurement techniques to allow for radially dependent flow profiles.
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