An application of low tube voltage in combination with simultaneous iterative reconstruction technique incerebrovascular CT imaging

Objective: To study the impacts of tube voltage and simultaneous iterative reconstruction technique on the image quality and radiation dose in cerebrovascular imaging and determine the optimum tube voltage and iterative reconstruction parameters. Methods: A home-made blood vessel of brain was constructed using an ATOM 701-D adult male phantom head and iodine-water mixture contrast agent. A 320-row volume CT was used to scan the home-made brain at tube voltages of 80, 100 and 120 kv in combination with off, mild, standard and strong iterative reconstruction levels(12 protocols in total), respectively. Tube current and other parameters were not changed during scanning. CT value of the transverse blood vessels and its corresponding noise, CT value of brain tissue around blood vessels and its corresponding noise, signal-to-noise ratio(SNR) and contrast-to-noise ratio(CNR) were obtained. One-Way ANOVA analysis was applied to investigate the impacts of different tube voltages and simultaneous iterative reconstruction levels to image quality. Results: Compared with group 120 kv, the CTDIvol, dose length product(DLP), effective dose(ED) of group 100 kv and 80 kv reduced 39.29%, 39.52%, 39.42% and 66.88%, 67.02%, 67.31% respectively. When the tube voltage was kept constant, blood vessel noise, noise of brain surrounding blood vessels, SNR and CNR showed statistical difference(P0.05), while CT values of blood vessel and brain tissue around blood vessels had no statistical difference(P0.05) at different iterative reconstruction levels. When iterative reconstruction level was not changed and tube voltage was varied, both CT values of blood vessel and blood vessel noise exhibited statistical difference(P0.05), CT values of brain tissue around blood vessels, SNR and CNR had no statistical difference(P0.05), and noise of brain tissue around blood vessels showed statistical difference(P0.05) at AIDR 3D off and mild levels and no statistical difference(P0.05) at standard or strong levels. Conclusion: High-quality cerebrovascular imaging can be acquired at a tube voltage of 100 kv in combination with a standard or strong level of iterative reconstruction algorithm.