Image Quality and Radiation Dose of Lower Extremity CT Angiography in 128 Slice Dual-Source CT: Comparison of High Pitch and Low Pitch

Purpose: The objective of this study is to compare image quality and radiation dose of high pitch (3) CT angiography (CTA) with 128-slice dual-source CT in lower extremity arteries with that of low pitch (0.6) CTA. Materials and Methods: A total of 136 patients were divided into two groups; high pitch (3) group included 67 patients and low pitch (0.6) group included 69 patients. For quantitative analysis, we calculated the mean arterial attenuation, mean coefficient variation of arterial attenuations, mean contrast-to-noise ratio, mean figure of merit (FOM), and mean standard deviation of CT density of muscle. In addition, visual scores were used for qualitative evaluation, and radiation doses were reported in the two groups. Results: The mean dose-length product was decreased by 31% at high pitch (409.49 ± 37.71 mGy·cm vs. 592.98 ± 59.69 mGy·cm), and the mean volume CT dose index was also significantly decreased at high pitch (2.91 ± 0.14 mGy vs. 4.70 ± 0.30 mGy). However, other quantitative analysis showed no significant intergroup differences, except in mean FOM. Visual scores showed no significant intergroup difference. Conclusion: Despite changing the pitch from 0.6 to 3, the image quality of CTA was not degraded and radiation dose was reduced by 31%. KCI Citation Count: 0