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Purpose: To prospectively compare the image quality between mean temporal CTA reconstructed from liver perfusion CT datasets and conventional CTA.Materials and Methods: All patients gave written informed consent for this institutional review board–approved study.16 patients with liver focal lesions were enrolled.The study CT protocol included a perfusion CT(70 kVp,18 spiral scans,71s total acquisition times)and conventional standard dual-energy arterial and portal venous scans performed 15 minutes later.Mean temporal arterial(mTA)and portal venous(mTPV)images were manually reconstructed from perfusion CT dataset.The CT attenuation values and SD values at the right main hepatic artery(RHA),main portal vein(MPV),right portal vein(RPV),left portal vein(LPV)and right liver parenchyma(RLP)were measured.Signal-to-noise ratio(SNR)and vessels-to-liver contrast-to-noise ratio(CNR)were calculated.Subjective image quality of RHA,MPV,RPV,LPV,artery/portal vein in segment 4 and 8(A4,A8,P4,P8)was determined on a 4 grade scale(1 = non-diagnostic to 4 = excellent).Venous contamination was determined on a 4 grade scale(0 = none to 3 = severe).The furthest visible branches of hepatic artery/portal vein were also counted.Paired T test was conducted to evaluate differences in CT values,SNR and CNR.Objective image quality,venous contamination and furthest visible branches were compared by Wilcoxon paired test.Results: CT values of liver parenchyma were significantly lower and CT values of RHA and MPV were significant higher in mean temporal images compared to conventional ones(P<0.05).All measured CNR were significantly higher in mTA and mTPV images compared to conventional ones(all P<0.001),while SNR showed no significant differences(P>0.05).Subjective image quality in P4 and P8 were better in mTPV images(P<0.05),while the rest were comparable.The mTA and mTPV images showed less venous contamination and depicted further arterial/portal vein branches than conventional CTA(P<0.01).Conclusion: Mean temporal CTA images reconstructed from 70kVp liver perfusion CT has higher CNR,less venous contamination and could depict further vessel braches.It can obtain similar or better image quality compared to conventional CTA.