Wahle A, Prause GPM, DeJong SC, Sonka M:


Geometrically Correct 3-D Reconstruction of Intravascular Ultrasound Images by Fusion with Biplane Angiography - Methods and Validation.

Transactions on Medical Imaging, IEEE Press

Volume 18, Number 8, Page 686-699, August 1999

Comprehensive journal paper describing the entire fusion approach and its in-vitro validation (in-vivo) (Paper) (Images) (Links)

Abstract: In the rapidly evolving field of intravascular ultrasound (IVUS), the assessment of vessel morphology still lacks a geometrically correct 3-D reconstruction. The IVUS frames are usually stacked up to form a straight vessel, neglecting curvature and the axial twisting of the catheter during the pullback. Our method combines the information about vessel cross-sections obtained from IVUS with the information about the vessel geometry derived from biplane angiography. First, the catheter path is reconstructed from its biplane projections, resulting in a spatial model. The locations of the IVUS frames are determined and their orientations relative to each other are calculated using a discrete approximation of the Frenet-Serret formulas known from differential geometry. The absolute orientation of the frame set is established utilizing the imaging catheter itself as an artificial landmark. The IVUS images are segmented using our previously developed algorithm. The fusion approach has been extensively validated in computer simulations, phantoms, and cadaveric pig hearts.

We have developed and validated a comprehensive system for a geometrically correct 3-D reconstruction of coronary arteries based on fusion of IVUS and biplane angiography. Existing well-established systems for both IVUS segmentation and geometrical reconstruction from biplane angiograms have been incorporated. The use of an automated pullback device is inevitable in order to obtain an accurate reconstruction of the transducer's trajectory and a correct determination of the IVUS frames. Although our method showed excellent results in computer simulations, the in-vitro application in phantoms and cadaveric pig hearts uncovered influence from several sources of distortion, mainly caused by mechanical components of the setup. The systematic nature of these distortions holds a substantial promise for the successful development of an automated correction procedure.