Yun Shen PhD, Presenter: Employee, General Electric Company Researcher, General Electric Company

Shuai Zhang, Abstract Co-Author: Nothing to Disclose

Kefeng Zhou, Abstract Co-Author: Nothing to Disclose

Jian He MD, PhD, Abstract Co-Author: Nothing to Disclose

Ying Guo, Abstract Co-Author: Employee, General Electric Company

Bin Zhu MD, PhD, Abstract Co-Author: Nothing to Disclose

Gemstone spectral imaging (GSI) has the ability to correct beam hardening artifact at static status. However the feasibility of GSI to reduce beam hardening artifact at pulsating status is not sure. This study is to assess whether gemstone spectral imaging can reduce bobbing beam hardening artifact and determine the optimal monochromatic levels to minimize the influence of beam hardening artifact caused by iodine contrast agent of high concentration.

a polypropylene phantom in motion(frequency of 10bmp and amplitude of 10mm) with a polypropylene tube(diameter of 18mm,iodine concentration of 150mg/ml in tube) in center and eight polypropylene tubes(iodine concentration of 12mg/ml in tube) arranged clockwise with diameter(2-16mm,interval of 2mm) in outer circle underwent CT (Discovery CT750 HD) scans with GSI mode. All data were transferred to AW4.4 Workstation to obtain one set of polychromatic (POLY) images (140kVp) and 11 sets of monochromatic (MONO) images (40-140keV, 10keV step). The noises in background and in the region between central tube and the 16mm tube were measured to calculate artifact index (AI) in all 12 sets of images. AI and background noise (BN) were compared between the POLY and MONO images. AI is defined as the square root of the squared noise difference between region of interest and background.

BN at 60keV and 70keV were 4.98(SD,0.51) and 6.11(SD,0.30),respectively, which were significantly lower than other MONO sets and POLY set(p<0.05). There was significant difference in background noise between 60keV and 70keV (p=0.032). AI at 70keV (1.94;SD,0.82) was the lowest among all 12 sets. The differences in AI between 70keV and other sets were significant (p<0.05).The larger diameter of test was, the more significant the artifact was.

GSI has the ability to correct beam hardening artifact at pulsating status. The monochromatic levels of 70keV can considerably reduce noise and artifact index compared with polychromatic images (140kVp)

GSI may provide a reliable method to reduce beam hardening artifact even targeted organs or tissue in bobbing, such as peristalsis ,breathing and so on.

Shen, Y, Zhang, S, Zhou, K, He, J, Guo, Y, Zhu, B, Can Gemstone Spectral Imaging Correct Beam Hardening Artifact When Targeted Phantom at Pulsating Status?.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11034659.html