The Practical Value Of Energy Spectral CT In Reduce Metal And Beam Hardening Artifacts

Objective:To evaluate the practical value of energy spectral CT in reduce metal artifacts and beam hardening artifacts.Material and Methods:41patients with metal implants were underwent GSI (Gemstone spectral imaging) examination and blend energy images were acquired,the spectrum analysis was used to obtain the monochromatic images by the special GSI viewer.Eleven groups monochromatic images were obtained from40KeV to140KeV and every10KeV one group.①Subjective analysis:all image quality were analyzed and scored into3、2、1、0by three experienced radiologists independent and blinded(4=without artifact,3=few artifacts,2=some artifacts,1=serious artifacts).②Quantizing analysis:For every patient one group monochromatic images and blend enery images were selected two heaviest artifacts level and no or less artifacts level, the SD value of the region of interest (ROI)were meatured (Named:SD1、SD2、SDcontrast) and the artifact index(AI) of artifacts were calculated,and Statistical analysis was accomplished with SPSS17.0soft package.Results:All AI and radiologists’ scores were recorded and analysised. There were significant statistical differences between energy spectral images and blend energy images(P<0.05), that is to say, the image quality of energy spectral were significantly better than those of blend energy.The monochromatic images at70KeV was the boundary for reducing metal artifacts and110KeV was the best point for image quality. Conclusion:Our investigation showed that energy spectral CT possess superiority in decreasing the artifacts and will provide high image quality in the area with metal implants.