Wahle A, Krauß U, Oswald H, Fleck E:


Inter- and Extrapolation of Correction Coefficients in Dynamic Image Rectification.

Computers in Cardiology 1997, Lund SE, IEEE Press

Volume 24, Page 521-524, 1997

Final results of the previously reported study (Images) (Links)

Abstract: High level angiographic image analyses systems like those for 3-D reconstruction of entire vascular trees require propper corrections of geometric image distortions. Due to the fact that distortion patterns are not static, a dynamic image rectification method has to be applied for each different angulation. We aimed to avoid major impairment of the clinical routine, using minimal information as reference only. Since the coefficients of the correction polynomial highly correlate with the basic image rotation, our method reliably eliminates geometric distortions even for intermediate angulations without the need of separate grid imaging.

The accurate 3-D reconstruction of vascular systems from biplane angiographic projections provides the basis for the quantitative assessment of complex heart diseases, especially diffuse alterations. Compared to conventional Quantitative Coronary Angiography, which is restricted to local obstructions, the several distortion effects of x-ray systems have to be corrected more carefully. For example, remaining rotations or decenterizations of the biplane images cannot be accepted for 3-D analyses. On the other hand, the clinical routine does not allow phantom meassurements (i.e. imaging a regular grid) during patient examination. To overcome this problem, we developed a method to rectify angiographic images that considers both static and dynamic distortion patterns, but that needs only four markers on each image intensifier to calculate individual correction functions including centering and rotational alignment.