X-ray CT metal artifact reduction using wavelets: Arm application for imaging total hip prostheses

Traditional computed tomography (CT) reconstructions of total joint prosthe ses are limited by metal artifacts from corrupted projection data, Publishe d metal artifact reduction methods are based on the assumption that severe attenuation of X-rays by prostheses renders corresponding portions of proje ction data unavailable, hence the "missing" data are either avoided tin ite rative reconstruction) or interpolated tin filtered backprojection with dat a completion; typically, with filling data "gaps" via linear functions). In this paper, we propose a wavelet-based multiresolution analysis method for metal artifact reduction, in which information is extracted from corrupted projection data. The wavelet method improves image quality by a successive interpolation in the wavelet domain. Theoretical analysis and experimental results demonstrate that the metal artifacts due to both photon starving a nd beam hardening can be effectively suppressed using our method, As compar ed to the filtered backprojection after linear interpolation, the wavelet-b ased reconstruction is significantly more accurate for depiction of anatomi cal structures, especially in the immediate neighborhood of the prostheses, This superior imaging precision is highly advantageous in geometric modeli ng for fitting hip prostheses.