TOWARDS A GEOMETRICALLY CORRECT 3-D RECONSTRUCTION OF TORTUOUS CORONARY-ARTERIES BASED ON BIPLANE ANGIOGRAPHY AND INTRAVASCULAR ULTRASOUND

At present, 3-D reconstructions of coronary vessels are generated from intravascular ultrasound (IVUS) by stacking up ECG-gated segmented IV US frames of a pullback sequence. This simplified approach always resu lts in straight vessel reconstructions and, therefore, gives an incorr ect representation of tortuous coronary arteries. A more realistic rec onstruction of tortuous vessels may be obtained by data fusion with bi plane angiography. The 3-D course of the vessel is first derived from the angiograms and then combined with the segmented IVUS images. In th is paper, we focus on two problems associated with the data fusion met hod: The definition of the pullback path and the estimation of the IVU S catheter twist during pullback. A robust algorithm for calculation o f tortuosity-induced catheter twist is reported that is based on seque ntial triangulation of the 3-D pullback path. The method is analyzed w ith computer simulations and validated in helical vessel phantoms. A l argely automated data fusion approach is proposed and applied to tortu ous coronary arteries in cadaveric pig hearts.