A backprojection weight-based FDK reconstruction algorithm for cone beam digital subtraction angiography

Cone beam artifacts increase along with the larger cone angle because the scanning trajectory of the cone beam DSA does not sufficiently satisfy data conditions. Aimed at the characteristics of missing data in Radon space, we propose a Backprojection Weighted-FDK (BPW-FDK) algorithm for cone beam DSA. A new backprojection weight is presented to compensate for the missing data away from the rotating track for reconstruction region expansion. The images reconstructed from simulated noiseless projections, projections with noise, and real projections from an internally developed 3D-DSA scanner show that the proposed algorithm is able to sufficiently suppress artifacts away from the rotating track for large cone angle and provide more homogeneous image contrast. Compared to Parker-FDK algorithm, normalized mean square distance criterion and normalized mean, absolute distance criterion of BPW-FDK decreased by 5%. Its accuracy and speed make BPW-FDK algorithm suitable for image reconstruction of real large cone beam DSA.