Intravascular ultrasound(IVUS) can provide clear real-time cross-sectional images with lumen and plaque. Affected by pulse

the collected sequential images of the coronary artery

will be overlapped and distorted. As a result

the relativity between image sequences is destroyed. And the veracity of border detection of quantificational measurements and of reconstruction can not be achieved. In this paper

a new phasic registration technique without hard ware is used to resample the sequential images at the same phase. Then those resampled images are traced by a improved border detection technique based on fast active contour model. The experimental result shows significant accordance between the automatically detected luminal and vessel areas and the manual tracings with high correlation coefficients and small system error and the method can be a reliable and accurately way of diagnostis.