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PURPOSE To evaluate CT attenuation homogeneity and reliability of 16cm wide-detector compared with 4cm standard-detector technique on revolution CT at different tube voltage with a phantom experiment study.METHOD AND MATERIALS A phantom(QSP-1,FUYO)with 2 cylindrical tubes of 18-mm-diameter and16-cm-length placed into water tank was used.One was in central region filled with saline and the other was in periphery region filled with contrast medium concentration of 20.0 mg/mL.The phantom was scanned on Revolution CT at 80,100,120,and 140 kVp using both axial 16cm wide-detector protocol and helical 4cm standard-detector protocol with 5mm thickness,respectively.Circular regions of interest of same area were placed at the center of each tube to measure CT attenuation and the standard deviation(SD).CT attenuation homogeneity of each tube was evaluated by variation range(VR: maximum attenuation-minimum attenuation)and degree of dispersion(DD:defined as percentage of VR divided by mean attenuation),and coefficient of variation(CV: defined as percentage of SD of CT attenuation divided by mean attenuation).Data were analyzed by using paired t test.RESULTS The variation range(VR)of CT attenuation,degree of dispersion(DD)and coefficient of variation(CV)of 70,80,100,120 and 140kVp with 20mg/ml iodine contrast medium was(22.89HU,2.21%,0.58%),(10.77HU,1.29%,0.38%),(12.12HU,1.94%,0.56%),(15.77HU,3.21%,0.76%)and(19.38HU,4.71%,1.20%)using axial 16-cm wide-detector scanning protocol whereas those values using helical 4-cm standard-detector scanning protocol were(16.48HU,1.57%,0.50%),(12.89HU,1.54%,0.44%),(17.73HU,2.84%,0.91%),(8.92HU,1.81%,0.48%)and(15.48HU,3.75%,1.13%).There were no significant differences between these two protocols in VR of CT attenuation,DD and CV(P>0.05,respectively).CONCLUSION Axial 16-cm wide-detector scanning protocol on revolution CT at different tube voltage can provide the same CT attenuation homogeneity and reliable CT value with helical 4-cm standard-detector scanning protocol.It will have good potential clinical feasibility in CT-based myocardial ischemia evaluation such as quantitative angiography,transluminal attenuation gradient,myocardial perfusion and CT-derived fractional flow reserve.