Limitations of the manual pullback in intracoronary ultrasound imaging

Intravascular ultrasound (IVUS) may provide highly accurate information about the cross-sections of coronary and other vessels. By pulling the transducer back inside of the vessel, a continuous stream of cross-sectional data is obtained. However, the images have to be assigned to actual locations and in their proper orientations to allow reliable analyses. In this paper, we focus on the errors introduced by the catheter pullback, which is still performed mostly manually and unsupervised in clinical routine. However, even in idealised in-vitro studies several effects occur. We could measure a real pullback speed of 1.14±0.34 mm/s where a constant speed of 1 mm was instructed. Absolute orientations and relative twists of the IVUS images were loaded with RMS errors of 24.030 and 5.010, respectively, between different pullbacks of the same artery. Especially, these errors have to be considered for in-vivo assessments to avoid possible distortions of volumetric and other quantifications