Evaluation Strategies for Metal Artifact Reduction Approaches in CT: a Literature Survey

Metal-induced artifacts are known to degrade CT image quality and deteriorate the quantitative value of the images. Therefore, numerous metal artifact reduction techniques have been proposed and their performances have been evaluated using different qualitative or quantitative approaches. Various approaches and measures have been applied for the validation process visual assessment of the corrected images being one of the most commonly applied techniques. A high proportion of the presented techniques are not properly validated in the clinical environment, which hampers an unbiased comparison of the techniques and as such the clinical acceptability of the techniques remains questionable. Accurate quantitative evaluation of the processed images guarantees the reliability of the correction method. The main motivation of this work was to present the qualitative and quantitative validation approaches and metrics used in various metal artifact reduction studies in both phantom and clinical experiments. Considering the challenging task of validation of the clinical studies, where the gold standard is not present, having a proper knowledge about the potential solutions would assist the researchers to apply the right validation approaches.