A new software correction approach to volume averaging artifacts in CT.

The nature of artifacts in computed tomography, due to nonlinear partial volume effects, is briefly reviewed. A methodology for correction of these artifacts proposed. This methodology utilizes a correction algorithm for post-processing the original reconstructed CT image. The algorithm utilizes local CT values to predict the probability of volume averaging of bone, air and tissue, and incorporates information from the original image on the spatial extent of the averaging, to correct the nonlinear effects. The algorithm is successfully demonstrated on mathematical phantoms, wherein volume averaging can be introduced over central targets and/or peripheral annuli of tissue, bone, and air. The algorithm is also demonstrated on actual CT brain scans but only for its qualitative effects. It is pointed out that higher order corrections, to be reported in future publications, will further correct the actual clinical scans.