Preliminary applications of spectral CT imaging in angiography of bronchial artery with low concentration of iodine contrast a-gent

TANG Jun; DONG Jiang-ning; WEI Chao; LI Nai-yu; WEI Shu-hua; GAO Fei; GAO Na

Abstract：Objective To investigate the feasibility of spectral CT imaging in angiography of bronchial artery with low concentration of iodine contrast agent .Methods 20 patients in our hospital consecutively underwent enhanced chest CT scan on GSI mode (Discovery CT750 HD ,GE healthcare) .The injection parameters were 1 .2 ml/kg of injection volume , and 4 .0 ml/s of injection speed with iodixanol (270 mgI/ml) .SmartPrep was used to trigger the scan .The source images were conveyed to AW 4 .5 workstation and optimal keV images were obtained by GSI viewer software .We compared 140 kVp QC images (Quality Check) and the optimal keV images after measuring CT value and SD value ,and calculated CNR and SNR of bronchial artery on each patient .5-point scale was used to compare the image quality by 2 experienced radiolo-gists independent and blinded .Results The mean CT value ,mean CNR and mean SNR of the optimal keV images (HU :269 .22 ± 77 .23 ;CNR:35 .1 ± 21 .23 ;SNR :45 .10 ± 23 .32) were statistically higher than those in QC images (HU :160.53 ± 45 .74 ;CNR:12 .23 ± 9 .30;SNR:31 .95 ± 17 .62) ( t =17 .823 ,9 .865 ,8 .268 ,P <0 .001) .The subjective score in the optimal keV images (3 .63 ± 0 .92) was higher than that of QC images (2 .57 ± 0 .90) ,( t =13 .608 ,P <0.001) .Totally ;55 bronchial arteries were involved in the study .46 (84% ) of them in optimal keV group met the best quality imaging ,but only 28 (51% ) bronchial artery of QC images met .There was a strong correlation between two phy-sicians (kappa=0.745 ,P <0 .01) .Conclusion Low concentration of contrast agent combined with spectral CT imaging gets acceptable image quality in CTA of bronchial artery ,which can reduce contrast agent does in different degrees .