单次对比增强双源CT双能肺灌注成像扫描及重组参数的优化

Optimization of Scanning and Reconstruction Parameters in Dual Energy CT Lung Perfusion Imaging Using Dual Source CT by Single Contrast Enhancement

目的探讨不同扫描技术对双源CT(DSCT)双能肺灌注成像的影响,优化扫描和重组参数。资料与方法在相同对比剂浓度、负荷和注射流率前提下,60例患者随机分为5组,组1～3:利用人工智能触发扫描trigger技术,将感兴趣区设在肺动脉主干,当CT值达到100 HU时,再分别延迟3 s、6 s、9 s后扫描自动开始,其余扫描参数均为探测器准直14 mm×1.2 mm,球管旋转时间为0.5 s,螺距为0.5,重组层厚1.5 mm,间隔1.0 mm,足头方向。组4:头足方向,其他扫描参数同组2;组5:重组层厚1.5 mm,间隔1.5 mm,其他扫描参数同组2。测量升主动脉、肺动脉主干以及上腔静脉的CT值,并观察肺动脉分支显示级别和上腔静脉线束硬化伪影出现情况,评价DSCT双能肺灌注及肺动脉CT血管造影(CTA)的图像质量。结果与其他组相比,组2肺动脉强化值较高,上腔静脉强化值较低且线束硬化伪影较少,肺动脉5级分支显示清晰,同时具备优良的双能肺灌注和肺动脉图像质量,差别有统计学意义(P<0.05)。结论在相同对比剂浓度、负荷和注射流率前提下,组2的扫描方案可获得满意的肺双能灌注成像及肺动脉CTA的图像质量,结合临床实用情况,建议采用组2的扫描方案。

Objective To evaluate the effect of different scanning and reconstruction parameters on image quality of dual energy lung perfusion imaging using dual source CT（DSCT）.Materials and Methods 60 patients were divided into 5 groups,which same identical burden and injection speeding of contrast medium were adopted.Group 1 to 3 scanning was triggered by a bolus-tracking technique and image acquisition started 3,6,9s respectively,14 mm×1.2 mm detector collimation,0.5-second gantry rotation time,pitch of 0.5,reconstruction slice thickness 1.5 mm,interval 1.0 mm,and caudal to cranial direction.Group 4,cranial to caudal direction;group 5,reconstruction slice thickness 1.5 mm,interval 1.5 mm;other parameters of group 4 and 5 were the same with group 2.CT value on ascending aorta,pulmonary trunk,and superior vena cava were measured.Visualization scale of pulmonary artery and beam hardening artifact of superior vena cava were observed.Image quality of pulmonary artery and dual energy lung perfusion imaging were evaluated.Results The higher pulmonary trunk enhancement,lower superior vena cava enhancement,less beam hardening artifact and 5 branches of pulmonary artery were clearly found in group 2 with good image quality of dual energy lung perfusion imaging and pulmonary CT angiography（CTA）,which compared with other groups,the differences had statistical significance（P0.05）.Conclusion Which same identical burden and injection speeding of contrast medium are adopted,scanning protocol of group 2 can provide better image quality of lung dual energy perfusion imaging and pulmonary CTA,however,the parameters of group 2 are recommended for clinical routine use.