Matching Virtual histology RF and IVUS images for cardiac synchronization

Intravascular Ultrasound (IVUS) provides detailed measurements of the arterial wall. However, during its acquisition, the contraction of the cardiac muscle provokes a relative motion of the transducer with respect to the artery. Consequently, the acquired images are disordered in space. Therefore, to enhance visualization of the coronary artery, volumes of IVUS images of each cardiac phase are needed, mainly for IVUS images that do not contain any external indicator of phase. Our solution is to use Virtual histology RF images as references, since they are acquired simultaneously with IVUS images and are synchronized with the ECG signal. Thus, this work presents a synchronization of IVUS images with RF images. The RF/IVUS comparison is based on the correlation within a circular region of interest, which can be automatically optimized by the algorithm. Our results show very good error rates inferior to 3%, though IVUS and RF images have different characteristics.