Seite - 45 - in Proceedings - OAGM & ARW Joint Workshop 2016 on "Computer Vision and Robotics“

3-DShapeRecoveryof theLeftHeartChamber from BiplaneX-RayProjectionsUsingAnatomicalA-Priori InformationLearnedfromCT RolandSwoboda1,2, JosefScharinger2, andClemensSteinwender3 1 ResearchCenterHagenberg University ofApplied SciencesUpper Austria,Austria roland.swoboda@fh-hagenberg.at 2 DepartmentofComputationalPerception JohannesKepler UniversityLinz,Austria josef.scharinger@jku.at 3 Clinicof InternalMedicine I GeneralHospital Linz,Austria clemens.steinwender@akh.linz.at Abstract Recovering the 3-D shape of the left heart chamber from bi-planar 2-D x-ray projection images is a challenging task sinceonly sparseandnoisydata isavailable for reconstruction. In thiswork,a3-D statistical shape model (SSM) of the left ventricular (LV) anatomy is learned from high-resolution CT data and utilized as a-priori information to solve the under-determined and ambiguous recon- struction problem. A 2-D/3-D registration method fits the SSM to the x-ray images of the patient by calculating simulated projections of the SSM and minimizing the difference between simulated and given projections. The presented approach is evaluated using simulated and real patient data. For patients where both projection images and CT data are available, the reconstructed LV is compared to the true shape known from CT. Our results show a good correspondence between recovered and trueshapes. UsingaSSMasanatomicala-priori information for reconstructionhelps in limiting the spaceofpossible solutions andallows togenerate statisticallyplausible shapes. 1. Introduction Cardiac diseases are one of the most common causes of death in the industrialized world today. In the case of acute myocardial infarction, for instance, interventional x-ray angiography is state-of- the-art for both treatment and diagnosis. To evaluate the viability of myocardium after infarction, a catheter is advanced into the left heart chamber (ventricle) and contrast agent is injected to opacify theventricular cavityduring radiation. Bi-planarcine-angiographicequipment isused toacquire two x-ray image sequences simultaneously from standard right anterior oblique (RAO) and left anterior oblique (LAO) views, seeFig. 1. 45