Objective To compare the quality of the images using different thresholds of automatic bolus tracking in 16梥lice spiral CT angiography of pulmonary arteries. Methods One hundred and twenty patients were randomly divided into four groups,and the automatic bolus tracking thresholds of 40,60,80 and 100HU in the pulmonary trunk were used respectively. The CT values of pulmonary artery, pulmonary vein and aorta among four groups were compared, at the same time the excellent rate of image under different thresholds were compared. Results The CT values of pulmonary artery, pulmonary vein and aorta among four groups had statistical difference,the excellent rate of image under different thresholds had significant difference(P＜0.001),there was significant difference between 40HU and the other three groups(P＜0.001), there was also significant difference between 60HU and the other two groups 80、 100HU(P＜0.001), compared the two groups 80、 100HU, no significant difference was found, the image quality was poor. Conclusion The bolus tracking thresholds of 40 HU in the pulmonary trunk is preferable.%目的研究不同智能触发监测点阈值条件下的CTA扫描效果,以期提高肺动脉CTA图像质量.方法 120例接受肺动脉CTA患者随机均分成Ⅰ、Ⅱ、Ⅲ、Ⅳ4组,分别以40、60、80、100HU作为监测阈值进行追踪触发扫描,比较肺动脉、肺静脉、主动脉强化CT值及肺动脉与主动脉强化CT值差值的组间差异,同时比较不同监测阈值下等级图像差异.结果肺动脉、肺静脉、主动脉强化CT值及肺动脉与主动脉强化CT值差值在4组间有显著性差异,不同监测阈值下等级图像有显著性差异(P<0.001).40HU与其它3组有显著性差异(P<0.001);60HU与80、100HU有显著性差异(P<0.001);80、100HU两组相比差异无统计学意义(P>0.05),图像质量较差.结论以主肺动脉干为监测点,40HU监测触发阈值时肺动脉强化CT值最大,可获得理想的肺动脉CTA图像.
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