Purpose
To develop a phantom and a method for evaluating the effectiveness of artifacts reduction algorithms from metal structures suppressing in the analysis of tissues with different locations and x-ray density.
Methods and materials
Phantom.A cylindrical 6-liter phantom with 10 test tubes and a 10x100 mm metal rod in its center was made [1]. Tubes were filled with an aqueous solution of K2HPO4at concentrations of 10, 50, 100, 200, and 300 mg/cm3to imitate a whole range of X-ray density of human tissues. Stainless steel, copper, and aluminum rods were used.
Study.The study was conducted on a Siemens Somatom CT in Dual Energy (DE) mode (100 kV, 250 mA and 140 kV, 483 mA) with and without Metal Artifact Reduction...
Results
Several studies showed an increase in the quality of images when applying methods of artifactsreductionin some special cases [2,3,4]. Thedevelopedphantom allowed us to obtain the following results.
There was no visible distortion on images without metal. A visual assessment of the MAR-processed images with a rod showed significant smoothing of the radial artifacts. Numerical analysis showed a bias of mean values within 9% for 140 kV and 5.5% for DE (stainless rod, 300 mg/cm3). For copper and aluminum rods, the mean intensity was not significantly...
Conclusion
The obtained results confirm the effectiveness of using DE and MAR when performing CT studies in cases with metal objects in the scanning area. The tool allows avoiding the appearance of artifacts on obtained images. However, the experience has shown possible multiple local increases in the level of noise in those areas in which substances with high X-ray densities are located. In addition, the quantitative analysis of such images should consider the possibility of some changes in the mean X-ray value.
The obtained results show...
Personal information and conflict of interest
D. Semenov; Moscow/RU - nothing to disclose S. Morozov; Moscow/RU - nothing to disclose A. Vladzymyrskyy; Moscow/RU - nothing to disclose K. Akhmad; Moscow/RU - nothing to disclose Y. Vasilev; Moscow/RU - nothing to disclose K. Sergunova; Moscow/RU - nothing to disclose
References
1. Phantom for evaluating the effectiveness of suppressing artifacts from metal structures in CT. Patent RF. No 190308. 2019
2. Pessis E. et al. Reduction of Metal Artifact with Dual-Energy CT: Virtual Monospectral Imaging with Fast Kilovoltage Switching and Metal Artifact Reduction Software // Semin. Musculoskelet. Radiol. 2015. Vol. 19, No 5. P. 446–455.
3. Jeong S. et al. Usefulness of a Metal Artifact Reduction Algorithm for Orthopedic Implants in Abdominal CT: Phantom and Clinical Study Results // Am. J. Roentgenol. 2015. Vol. 204, No...
