Computer assessment of hemodynamic severity of coronary artery stenosis from angiograms

A computer-assisted analysis of coronary obstructions from cineangiograms is presented, which includes both the geometric and hemodynamic evaluation of coronary stenosis severity. Single frame images are digitized into a 512 X 512 X 8 bit array after a cine-to-video conversion. Automatic edge tracking is performed using a combination of derivative and threshold methods. Vessel borders from two orthogonal views of the arterial segment are used to create a three-dimensional reconstruction of the stenosis, which serves as a basis for calculation of absolute and relative geometric dimensions, stenotic resistance and trans-stenotic pressure gradient for various given flow rates. A preliminary performance evaluation of this method was made by analysis of x-ray phantoms representing stenoses of known dimensions, which were filmed under quasi-clinical conditions. The results are discussed with respect to their accuracy and reproducibility.