734-6 ANGUS: A New Approach to Three-dimensional Reconstruction of Geometry and Orientation of Coronary Lumen and Plaque by Combined Use of Coronary Angiography and IVUS

Three-dimensional (3-D) vessel reconstruction using intravascular ultrasound (IVUS) is limited by the lack of information on the real vessel curvatures and the orientation of the IVUS catheter. To overcome these limitations a method was developed using data obtained from ANGiography and intravascular UltraSound (ANGUS). This technique provides real spatial geometry and orientation of coronary lumen and plaque. The artery is studied by IVUS during a pull-back (PB) of the IVUS catheter at a speed of 1mm/s. Start and end of the PB are recorded by biplane fluoroscopy (BF) and finally biplane coronary angiography (BA) is performed without changes in geometrical X-ray settings. Using a new computer program the contours of the lumen-plaque and plaque-adventitia boundaries are semi-automatically detected at 0.5mm intervals. BF allows geometrical reconstruction of the catheter trajectory, which is the path of the IVUS transducer during PB. Combined use of the IVUS data, the catheter trajectory and the lumen contours in the BA provides a unique 3-D reconstruction of coronary arteries without any evidence of an additional unknown geometric factor. Studying the trajectory in a vessel phantom of known dimensions a high accuracy was found (distance between reconstructed and real trajectory at any point<2 mm). First application in a human right coronary artery in-vivo (length: 75mm) showed a difference of 2% between the length of the reconstructed trajectory and the PB distance. Checking the locations of the origin of side-branches in the 3-D reconstruction and BA differences of less than 2mm were found. Location and shape of stenoses in simulated projections of the reconstructed lumen matched well with BA. However, at the site of a previous PTCA luminal haziness in angiography and dissection observed by IVUS may slightly reduce the accuracy of this technique. Thus combining ANGiography and intravascular UltraSound (ANGUS) is promising and provides a unique reconstruction of 3-D coronary geometry.