Correction of geometric artifacts in intravascular ultrasound imaging during stent implantation

A model has been developed for correcting geometric artifacts observed in intravascular ultrasound imaging during coronary artery stent implantation. Geometric artifacts occur when the position of the transducer inside the stent is off-centered and inclined. In coronary applications, the position of the catheter changes a lot due to the curved nature of the arteries. This gives images that do not correspond to the expected cross section of the stent and lead to ambiguous interpretation by physicians. The authors' work consists of estimating and correcting artifacts in all stent images where the catheter is positioned off-centered and not parallel with the vessel axis. Estimation is made using the analytical model of geometric artifacts which predicts positioning of the ultrasound catheter inside the stent (tilt angle, off centering in both directions x and y, azimuth angle). Correction consists in using the predicted values of artifacts to calculate the equivalent stent image seen by a centered and non-inclined catheter. The "corrected" image is then used to compute clinical parameters for quantitative analysis of stent implantation.