| Purpose:To evaluate portal venography of radiation dose and conspicuity with a new multidetector computed tomography(CT)protocol that combines spectral CT and split-bolus injection.Materials and methods:This study was approved by the institutional review board and compliant with HIPAA.The requirement for informed consent was waived.Collected between September 2014 and March 2016 in our hospital patients with CT portal vein check,choose the patients,the CHILD A/B/C level subjects or hepatitis were randomly divided into two groups,underwent CT with either a standard or split-bolus spectral CT protocol depending on scanner availability.Split-bolus spectral CT with portal venous phases in a single scan: The standard protocol included :the use of Smart trigger for three phase scanning method.The two groups of CTPV image subjective and objective assessment by two experienced professor,the heteroscedastic t test were used for statistical analysis.Results:There were no significant differences in age,weight,and body mass index between patients in the standard CT and split-bolus spectral CT group.When portal vein imaging showed the best single image energy at 60 kev energy.Portal vein improved degree of quantitative evaluation by spectral CT: there were significantly more in the split-bolus group(P<0.05).By 60 kev image reconstruction,portal vein improved degree of quantitative evaluation: 1、all branches of the portal vein system CT value comparison: the experimental group A/B/C group is significantly higher than control group(P < 0.001);The experimental C group in outside of portal vein were higher than in the control way(P=0.002).2、CNR and SNR of portal: experimental liver inside and outside of portal vein and portal vein branch CNR and SNR is slightly higher than that of control group,each group A/B/C comparison between group and group had no statistical difference.3、Portal subjective score analysis: the subjective score higher than the control group(P < 0.01),Contrast in the way of subjective score comparison: A/B/C no statistical difference between groups(P > 0.05).4、Analysis of portal vein radiation dose: the radiation dose groups in terms of A/B/C are far lower than the control group(P < 0.01);Within each group are no statistical differences(P > 0.05).However,Portal venous conspicuity and CNR SNR were higher with the 60-ke V split-bolus protocol(CNR:(14.54 ±5.25)HU,(24.34±7.94)HU and(21.71±7.17)HU;SNR:(30.54±6.00)HU,(29.13±4.57)HU and(26.95±5.76)HU,respectively)than with the three phase scanning method of the standard protocol CNR:(12.82±4.42)HU,(20.13±6.19)HU and(18.67±5.53)HU;SNR:(29.05±7.36)HU,(28.00±8.51)HU and(25.93±6.06)HU,respectively(P>0.05).Score analysis of portal venous conspicuity: the split-bolus protocol scored an average of 14.25±1.02,the standard protocol scored 12.52±1.75,(P<.001).Radiation dose was(17.36±7.51)m Sv with the standard protocol and(8.10±0.97)m Sv with the split-bolus protocol(P<.001).Conclusion:1、Spectral multidetector CT portal vein imaging with split-bolus protocol,achieve greater branch of portal vein and display than that with multiphase CT,with a 53% reduction in radiation dose.2、Spectral multidetector CT portal vein imaging with single phase,under different of the cirrhosis CHILD classification of the liver function,it has obtained the good imaging effect. |
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