Accurate 3D reconstruction of complex blood vessel geometries from intravascular ultrasound images: in vitro study

We present a technique that accurately reconstructs complex three dimension al blood vessel geometry from 2D intravascular ultrasound (IVUS) images. Bi plane x-ray fluoroscopy is used to image the ultrasound catheter tip at a f ew key points along its path as the catheter is pulled through the blood ve ssel. An interpolating spline describes the continuous catheter path. The I VUS images are located orthogonal to the path, resulting in a non-uniform s tructured scalar volume of echo densities. Isocontour surfaces are used to view the vessel geometry, while transparency and clipping enable interactiv e exploration of interior structures. The two geometries studied are a bovi ne artery vascular graft having U-shape and a constriction, and a canine ca rotid artery having multiple branches and a constriction. Accuracy of the r econstructions is established by comparing the reconstructions to (1) silic one moulds of the vessel interior, (2) biplane x-ray images, and (3) the or iginal echo images. Excellent shape and geometry correspondence was observe d in both geometries. Quantitative measurements made at key locations of th e 3D reconstructions also were in good agreement with those made in silicon e moulds. The proposed technique is easily adoptable in clinical practice, since it uses x-rays with minimal exposure and existing IVUS technology.