Influence of gantry rotation time and scan mode on image quality in ultra-high-resolution CT system

Objectives To investigate the image quality of helical scan (HS) mode and non-helical scan (non-HS) mode on ultra-high-resolution CT in different gantry rotation time. Methods Graphical AbstractUltra-high resolution CT scanned eleven cadaveric lungs with the following rotation time with tube current of 200 mA and 0.25 mm collimation: View Large Image Figure Viewer Download Hi-res image Graphical AbstractHS with 1.5 s/rot (HS200 mA/1.5 s), View Large Image Figure Viewer Download Hi-res image Graphical Abstractnon-HS with 1.5 s/rot (non-HS200 mA/1.5s), View Large Image Figure Viewer Download Hi-res image Graphical Abstractnon-HS with 0.75s/rot (non-HS200 mA/0.75 s), View Large Image Figure Viewer Download Hi-res image Results Overall image quality (score: 2.45) and noise (score: 2.42) of non-HS 200 mA/1.5s was statistically best (p < 0.0005). Overall Image quality and noise of non-HS200 mA/0.75 s (score: 2.0) was comparable to that of HS200 mA/1.5 s. CTDIvol of HS200 mA/1.5 s is 23.2 mGy. CTDIvol of non-HS200 mA/1.5 s, non-HS200 mA/0.75 s, non-HS200 mA/0.35 s is 19.2 mGy, 9.8 mGy, 4.7 mGy. Conclusion Overall image quality and noise of non-helical scan is better than that of helical scan in the same rotation time. Overall Image quality of non-HS200 mA/0.75 s is comparable to that of HS200 mA/1.5 s, though the radiation dose of non-HS200 mA/0.75 s is lower than that of HS200 mA/1.5 s.