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

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 A1 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). 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 detection accuracy of the systemic artery-pulmonary 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 group A2 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. Key words: Tomography, X-ray computer; Bronchial artery CT angiography; Image Quality; Radiation dose