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Transit time estimations from coronary angiograms

This X-ray angiography is the current gold standard for morphology based diagnosis of coronary arteries due to their spatial and temporal resolution. Transit time methods are applied on coronary angiograms to estimate the interval of time required for the contrast material to traverse the distance between two regions of interest. They represent an important prerequisite for estimating blood flow parameters like velocity or flow rate which characterize the hemodynamic patterns of blood vessels. In this article we perform an analysis of ten different transit time estimation methods on routine clinical angiographic data acquired at the Clinical Emergency Hospital of Bucharest by using the time density curves. Different coronary arteries are considered and the analysis is performed on raw data, filtered data and fitted data. The most robust methods are the mean transit time, the mean arrival time and the cross correlation method. Furthermore, the mean transit time and the cross correlation method tend to underestimate, while the rise time method tends to overestimate the transit time. Automated filtering and fitting methods improve the results significantly and should always be used in conjunction with transit time estimation methods.