3D x-ray angiography: Study of factors affecting projection data consistency

The use of a C-arm radiographic system for 3D reconstruction of opacified vasculature presents several computational and engineering challenges. Factors that may lead to inconsistency at the projection data set and subsequent reconstruction errors include image noise, variations in vessel opacification during the acquisition, and inaccurate determination of the imaging geometry. We have utilized simulations to study the effect of these factors on 3D reconstruction with algebraic reconstruction technique (ART) in order to identify possible artifacts and loss of image quality in the 3D image. Corrective measures designed to counter artifacts such as smoothing, averaging, and use of constraints with ART have been developed and validated. These studies have made it possible to identify the causes of artifacts in preliminary in vivo applications, and to estimate the tolerance for imperfections in data acquisition. Moreover, these works have established modifications to the reconstruction procedure for reducing image artifacts and improving image quality.