Research On Suppression Of Motion Artifacts In Intracoronary Ultrasonic Sequence

Intravascular Ultrasound (IVUS), combining noninvasive ultrasound technique with invasive interventional catheter technique, is a new imaging method for diagnosis and interventional treatment of vascular diseases, especially coronary artery diseases. There exists a kind of special artifact in continuous pullback Intracoronary Ultrasound (ICUS) sequences due to periodic cardiac motion and pulsatile blood. It appreciates in the ICUS sequences as a rotation and displacement of the vessel cross-section. And its effect in 3-D ICUS images has been described as a"saw-tooth-shaped"longitudinal appearance of the vessel wall. This is the main artifact that hinders the visualization of ICUS images, and affects the quantitative analysis and the accuracy of three dimensional reconstruction of blood vessel.Based on the comprehensive analysis of motion artifact's generation mecha- nism and manifestation,which is existing in the continuous pullback ICUS sequences, the suppression of motion artifact has been achieved in this dissertation. First, each ICUS image frame is segmented to extract the outer contours of vessel wall; then, the rigid motion between outer contours of the adjacent frames is calculated, including vessel translation and rotation; finally, after completing the separation of motion component and geometric component with spectral analysis, the motion artifact is suppressed through the compensation of motion component. The feasibility of this method is verified by the results of simulation and clinical images experiments.The advantages of this method do not require a dedicated ECG-gated acquisition device and its results aren't subject to the doctor's subjective factors. To the more importance, it does not abandon any useful ICUS frame, which ensures the integrity of ICUS images.