AN ATTEMPT TO 3D RECONSTRUCT VESSEL MORPHOLOGY FROM X-RAY PROJECTIONSAND INTRAVASCULAR ULTRASOUNDS MODELING AND FUSION

The emergency of interventional revascularization techniques in the tr eatment of atheromateous vascular diseases has resulted in the need fo r additional valuable diagnostic information about the 3D morphology a nd nature of the lesion. To overcome the Limitations inherent to commo n vascular imaging techniques, such as Digital Angiography (DA) which only gives partial information on lumen narrowing or Intravascular Ult rasound (IVUS) which provides randomly oriented transversal images, a 3D reconstruction of the vessel by fusion of X-ray and IVUS images has been developed. For that purpose, X-ray and IVUS images are acquired according to a well-defined protocol and useful information to be fuse d is extracted. A geometric model then leads to the determination of t he unknown parameters which allow the alignment of all data in a commo n reference frame. The registered data are then directly introduced in to a probabilistic reconstruction process using a Markovian modeling a ssociated with a simulated annealing-based optimization algorithm. Tak ing into account all the information available about the vessel, the m ethod avoids the uncertainties and ambiguities of a reconstruction bas ed only on one modality, and the probabilistic fusion solves the possi ble contradictions between both acquisitions. Results of vascular lume n 3D reconstruction are shown with data acquired on an excised dog aor ta. The accuracy of reconstruction of the lumen by data fusion is sign ificantly improved compared to results obtained with separate reconstr uction from angiographic or ultrasonic data. Further work will include introduction of vessel wall texture elements into the probabilistic f usion process to increase the amount of information gained by intravas cular ultrasonic tissue characterization. Copyright (C) 1996 Elsevier Science Ltd.