Comparative methods for metal artifact reduction in x-ray CT

To assess the performance of five metal artefact reduction (MAR) techniques for the assessment of computed tomography (CT) images of patients with hip prostheses. Five MAR algorithms were evaluated using simulation and clinical studies. The algorithms included one-dimensional linear interpolation (LI) of the corrupted projections in the sinogram, two-dimensional interpolation (2D), a normalized metal artefact reduction (NMAR) technique, a metal deletion technique (MDT), and a 3D prior image constrained projection completion approach (MAPC). The algorithms were applied to 10 simulated datasets as well as30 clinical studies of patients with metallic hip implants. Qualitative evaluations were performed by two blinded, experienced radiologists, who ranked overall artefact severity, as well as pelvic organ recognition for each algorithm, respectively. The simulated studies revealed that 2D, NMAR and MAPC techniques performed almost equally well in regions with dark streaking artefacts. However, in regions with bright streaking artefacts, LI outperformed the other techniques (p<;0.05). Visual assessment of clinical datasets confirmed the superiority of NMAR and MAPC in the evaluated pelvic organs and in terms of overall image quality. Overall, all methods performed equally well in artefact-free regions. However, NMAR and MAPC outperformed the other techniques in regions affected by artefacts.