Influence on radiation dose and image quality of bronchial artery CTA for high heart rate patients with single-cardiac dynamic volumetric scanning in 320-row CT / 中华放射医学与防护杂志

ABSTRACT

Objective To assess the influence on radiation dose and image quality of bronchial artery CT angiography for hemoptysis patients with high heart rate and free respiratory with single-cardiac dynamic volumetric scanning using 320-row CT.Methods During October 2016 and May 2017,totally 151 hemoptysis patients with heart rate ≥ 65 bmp and free-breathing were scanned for bronchial artery imaging with prospective ECG-gating 320-detector row dynamic volume CT.The patients were randomly divided into two groups,group A(81 cases) and group B(70 cases).Default multi-cardiac cycle scanning style was used for group A to generate multi-sector images A 1 which were reconstructed corresponding single-sector images A2.Single-cardiac periodic scanning was used to get single-sector images for group B.The effective doses (E) of two scanning types,the quantitative parameters of image quality [vascular CT value,image noise (SD),signal-to-noise ratio (SNR),contrast-to-noise ratio (CNR)] and subjective scoring of group B and A1,A2 were compared.The detection accuracy of the systemic artery-pulmonary circulation shunts was evaluated by ROC curve against digital subtraction angiography (DSA).The measurement data was analyzed by independent sample t test while the grade data was tested by independent sample nonparametric test.Results The median value of radiation dose in group B was significantly lower than that of group A (1.42 mSv vs.3.06 mSv,Z=-8.724,P＜0.05).There were no statistically significant differences in quantitative parameters and subjective scoring points of image quality between group B and group A2 (P＞ 0.05).The median subjective scoring points of group B was 4,which was better than that of group A1 (Z =-10.584,P＜ 0.05).The differences of SD,SNR,CNR betweengroup B and group A1 were statistically significant(t =-0.983,7.898,7.695,P＜0.05),and group B had higher SD,SNR and CNR.There was no significant difference in the mean CT values of the aorta and pulmonary artery between the two groups (P ＞ 0.05).The detection accuracy of the systemic arterypulmonary circulation shunts was moderately high in group B and group A2.The area under the ROC curve (AUC) was 0.891 and 0.864,respectively (Z=7.210,7.430,P＜0.05).The accuracy of group A1 was poor.The area under the ROC curve was 0.626 (Z=2.434,P＜0.05).The sensitivity of group B and groupA2 were 80％ and 76.2％,respectively (P＜0.05),and 28.6％ of group A1 (P＜0.05).Conclusions The 320-row single-cardiac periodic dynamic volume CT can effectively improve the image quality and the detection accuracy of the systemic-pulmonary circulation on CT,and reduce the radiation dose of the bronchial artery CT angiography.