Metal artifact reduction in computed tomography at head and neck region

Abstract

The common streak artifacts in computed tomographic images result from the metal implant in patients. Such the artifacts could suppress proper diagnosis or misdiagnosis in computed tomographic images. The purpose of this study is to develop the method for metal artifact reduction using MATLAB software and implement in both phantom and patients for head and neck computed tomographic imaging. The new algorithm of metal artifact reduction in computed tomographic images had been developed using MATLAB software. The homogeneous phantom, Alderson Rando phantom, and patients with a metal implant in the head and neck region had been scanned by Philips Brilliance Big Bore CT. Commercial Orthopedic metal artifact reduction (OMAR) and new algorithms were applied to the computed tomographic images in phantoms and patients with the metal artifact in the head and neck region. The quantitative analysis of image quality on a metal artifact of the head and neck region was evaluated in percent noise. The qualitative analysis in clinical imaging was evaluated in scoring by two radiation oncologists. In homogeneous and Alderson Rando phantoms, the new algorithm indicated higher efficiency in metal artifact reduction than OMAR. In contrast, for the head and neck computed tomographic image with metal artifact reduction, OMAR showed higher efficiency than the new algorithm. The new algorithm suppressed the artifact in homogeneous, anthropomorphic phantom and patients with a metal implant in the head and neck region approximate 40%, 40%, and 60%, respectively. The new algorithm of metal artifact reduction based on non-linear interpolation technique to suppress the metal artifact in computed tomographic images, use the unique technique to improve the image quality. The qualitative analysis by two radiation oncologists showed the comparable results of OMAR and new algorithm. The efficiency of the new algorithm is better than filtered back projection and metal artifact reduction for OMAR in homogeneous phantom and Alderson Rando phantom in the clinical range of the tube current-time, mAs. However, the efficiency of metal artifact reduction for OMAR is higher than a new algorithm and filtered back projection regarding percent noise. The image quality scoring by two independent radiation oncologists with the same experience showed comparable efficiency result of the new algorithm and OMAR.