An Automated User-friendly Software for Fast Computation of Blood Flow Velocity From Coronary Angiographic Images.

Thrombolysis in myocardial infarction frame count enables assessment of coronary flow but cannot measure coronary flow velocity (CFV), which is needed to examine microvascular function. To overcome this limitation, we introduce a semi-automated software for fast CFV computation using contrast bolus tracking techniques in angiography and compare its performance against experts. The study included patients undergoing coronary angiography. Two experts measured the CFV using the number of frames, segment length, and frame rate. Measurements were repeated for shorter segments and different projections, and their estimations were compared with the software. In total, 123 patients (152 vessels) were included. The software had excellent reproducibility in measuring CFV (intraclass correlation coefficient (ICC) = .995), which was superior to experts (ICC = .946) and provided similar estimations irrespective of the segment length (ICC = .992); conversely, the experts overestimated CFV in short segments. The reproducibility of the experts and the software was moderate when comparing CFV measurements in different projections (first expert vs software ICC = .807, second expert vs software ICC = .790, first expert vs second expert ICC = .885). The software provides reproducible CFV estimations that are close to experts' estimations. Further validation against wire-based functional techniques is needed to examine its potential in assessing microvascular function.