容积螺旋穿梭技术在肺动脉血管造影成像中的应用

Application of volume helical shuttle technique in pulmonary artery CTPA

目的:探讨在肺动脉血管造影成像(computed tomography pulmonary angiography,CTPA)中应用容积螺旋穿梭(volume helical shuttle,VHS)联合迭代重建技术与bolus tracking技术比较的优势。方法:前瞻性将32例患者纳入观察组,采用VHS进行CTPA扫描,注射对比剂8 s后启动扫描,进行5次(pass)扫描。回顾性分析对照组30例64排容积CT(volume computed tomography,VCT)所做CTPA资料,注射对比剂后采用bolus tracking技术,在肺动脉主干层面设监测处,阈值70 HU,达到阈值后自动触发。测量主肺动脉和右肺下静脉的CT值并记录主肺动脉CT值的标准差。由2名放射科医生使用5点评分法评价图像质量及诊断。结果:观察组主肺动脉的CT值为(287.51±38.08)HU,对照组为(279.21±89.09)HU,两组间比较无差异(P>0.05)。观察组成像密度差为(148.21±46.62)HU,对照组成像密度差为(83.81±38.13)HU,观察组成像密度差高于对照组(P<0.05)。在主观图像质量评价中观察组图像质量、肺动脉强化程度均高于对照组(P<0.05),运动伪影低于对照组(P<0.05)。结论:VHS技术操作简单,对病人配合程度要求低且容易捕捉到肺动脉强化的最佳期相。

Objective： To investigate the advantages of volume helical shuttle （VHS） combined with iterative reconstruction technology and bo- lus tracking technology applied to pulmonary artery angiography （ computed tomography pulmonary angiography, CTPA ）. Methods： 32 patients in the observation group were given CTPA scan with VHS for 5 times, starting scanning in 8 seconds after injection of contrast agent. A retrospective analysis of 30 cases in the control group was made. After injection of contrast agent, bolus tracking technology was employed to monitor the main pulmonary artery level, automatically triggering at the threshold of 70 HU. The CT values of the main pulmonary artery and the right lower pulmona- ry vein were measured, and the standard deviation of CT value of the main pulmonary artery was recorded. Two radiologists evaluated the image quality and made diagnosis by 5 point scale model. Results：The CT value of the main pulmonary artery in the observation group was （287.51± 38.08 ）HU, the control group was （279.21 ± 89.09 ）HU, and there was no differences between the two groups（ P 〉 0.05 ）. The composition im- age density difference （148.21±46.62）HU in the observation group was higher than that （83.81 ±38.13 ）HU of the control group. （ P 〈 0. 05 ）. In the subjective image quality evaluation, the quality and the enhancement degree of the pulmonary artery of the observation group were both higher than those of the control group （ P 〈 0.05 ）, and the artificial motion imaging was lower than that of the control group （ P 〈 0.05 ）. Con- clusion： VHS technique is easy to capture the best phase of pulmonary artery enhancement with the advantages of simple operating and low - level coordination from patients.