Application of flash dual-source CT at low radiation dose and low contrast medium dose in triple-rule-out (tro) examination

摘要

Objective: To evaluate the clinical imaging capacity of FLASH dual-source CT at low radiation dose and low contrast medium dose in thoracic aorta, pulmonary artery & vein and coronary artery. Method: One hundred and eight patients of thoracalgia were randomly divided into two groups; 60 cases (group A) received dual-source CT scan in flash model at 100 KV and contrast medium dose of 74 ml combined with digital subtraction angiography (DSA) examination; 48 cases (group B) received retrospectively. ECG-triggered high-pitch spiral acquisition at 120 KV and contrast medium dose of 101 ml. Several image reconstruction techniques were adopted for coronary artery, pulmonary artery and aorta. The imaging quality and the diagnostic value of this technique were evaluated. Coronary artery stenosis of group A was compared against the results of DSA examination. Results: The scan time in group A was obviously shorter than that of group B, i.e., t=0.7±0.1 s in group A and t=7.7±1.7 s in group A. The image reconstruction phase of coronary artery was 70.4±15.6% in group A, and the systolic phase accounted for 13.3% of the optimal reconstruction phase. Compared with group B, the radiation dose of group A decreased obviously, i.e. ED=2.7±0.7 mSv for group A and ED=21.6±6.0 mSv for group B. Moreover, less contrast agent was consumed in group A than in group B, which was 74 ml in group A and 101 ml in group B. The image quality of aorta and pulmonary artery & vein was grade 1 for all cases in group A, which was the same as with group B. The coronary artery images of group A had better quality, with score of 2.9±0.1. Of 780 segments, only 2 segments could be effectively diagnosed, showing no statistically significant differences from group B (P>0.05). The coronary artery stenosis revealed by dual-source CT for group A was not significantly different from that by DSA (P>0.05). Conclusion: FLASH dual-source CT scan at reduced radiation dose and reduced contrast medium dose used for triple-rule-out (TRO) examination achieved good image quality and clear visualization of blood vessels. Moreover, this CT scan technique is fast and rapid in diagnosis and suitable for extensive clinical settings.