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Objective To investigate the clinical application of low kVp scan using kV assist with adaptive statistical iterative reconstruction(ASiR)in abdominal CT.Methods 100 patients underwent abdominal CT on a new generation spectral CT scanner(Discovery CT,GE healthcare).The patients were divided into 2 groups for analysis.Group A(n=50)used KV assist protocol,which automatically selects an optimal kVp based on the scout view.The images of Group A were reconstructed twice using ASiR and FBP,respectively.The two sets of images are regarded as set 1 and 2.While Group B(n=50)was performed with the conventional 120kVp scan using auto mA protocol.The images of Group B were reconstructed using only FBP,and are named as set 3.The main parameters were setup with noise index of 10,auto mA ranges at 100-450mA and rotation time at 0.8s.CT values,SD values and CNR of CA,PV,liver,pancreas and image quality scores in abdomen were measured and calculated for the three sets.CTDIvol and DLP of each patient was recorded and compared.Rank-sum test and t test were adopted to analyze the data.Results The effective radiation dose of Group A(4.6±2.4mSv)was much lower(p=0.02)than that of Group B(6.6±3.1mSv),and dose reduction were 30.31%.The differences of the 3 sets of subjective rating scores in artery and venous phase were statistically insignificant(P=0.693).However,the noise of the 3 sets of images in dual-phase were(7.93±2.17),(10.71±2.65),(8.83±2.38)HU and(8.84±2.45),(11.28±3.82),(8.82±2.25)HU.The differences were statistically significant(F=17.283 and 14.224,P=0.00 and 0.00).Compared with the last two sets,CNR of CA in LAP,and of PV,liver,and pancreas in PVP of the set 1 were much higher(P<0.05).No statistically significant differences were found between the last two sets of images in CNR(P>0.05).Conclusion KV assist,combined with ASiR reconstruction,could reduce the radiation dose and provide better quality images compared with conventional abdominal 120 KVp CT.