双源螺旋CT大螺距Flash模式在肺动脉CTA成像技术中的应用

Application of dual-source spiral CT with high-pitch flash mode in CT pulmonary angiography

目的:探讨双源螺旋CT大螺距Flash模式、时间-密度曲线测试技术在肺动脉CT成像(computer tomography pulmonary angiography,CTPA)中运用的可行性。方法:将拟行CTPA检查的60例患者随机分为2组。对照组采用单源常规模式扫描,对比剂示踪技术。实验组采用双源大螺距Flash模式扫描,时间-密度曲线测试技术。对比剂均采用400 mg I/ml碘迈伦,其余扫描参数均相同。扫描结束后,将原始数据传至后处理工作站进行处理,分别采用图像质量评分及CT值、对比噪声比评价图像质量。结果:实验组及对照组共60例病人均成功完成CTPA检查,2组一般资料如性别、年龄、身高、体质量均无明显统计学差异(P值分别为0.752,0.605,0.319,0.523);实验组对比噪声比高于对照组(P值分别为0.028,0.030,0.001,0.012,0.020),2组肺动脉干、左右上肺动脉、左右下肺动脉CT值均无统计学差异(P值分别为0.362,0.986,0.373,0.584,0.931),实验组升主动脉、左右上肺静脉、左右下肺静脉CT值均低于对照组,差异有统计学意义(P值分别为0.000,0.001,0.000,0.003,0.000),且实验组的图像质量评分优于对照组(χ2=12.25,P=0.016;χ2=7.53,P=0.023);实验组对比剂用量(24 ml vs.50 ml)和辐射剂量[(5.27±1.94)m Sv vs.7.30±2.73)m Sv]低于对照组(P=0.011),实验组扫描时间明显短于对照组[(0.94±0.07)s vs.(4.71±0.37)s,P=0.000]。结论:在CTPA检查中,双源CT大螺距Flash模式、时间-密度曲线测试技术不仅能采集到理想的肺动脉影像,而且降低了患者的辐射剂量及对比剂用量,还有效缩短了患者的屏气时间。

Objective：To explore the feasibility of dual-source spiral CT with high-pitch flash spiral mode as well as time-density curve in diagnosing the clinically suspected pulmonary embolism （PE）. Methods：Sixty patients planed to receive CT pulmonary an- giography（CTPA） were randomly divided into two groups. Routine scan and bolus tracking monitoring were used in control group,while dual-source spiral CT with high-pitch flash spiral mode as well as time-density curve was used in experimental group. Contrast agents Iodine diftler with the concentration of 400 mgI/ml was applied in both groups. The parameter of CT scanning was the same in both groups. All CT original dates were transferred to Siemens workstation and were post-processed by VR, MIP, MPR and CPR tech- nology. The CTPA image quality was evaluated based on score of image quality, CT value, and contrast to noise ratio （CNR）. Results： All patients in two groups completed CTPA successfully. There was no difference in baseline characters including sex, age, height and weight between the two groups （P=0.752,0.605,0.319,0.523）. CNR of experimental group was higher than that of control group （P= 0.028,0.030,0.001,0.012,0.020）. There was no difference in CT value of pulmonary artery trunk, RSPA, RIPA, LSPA and LIPA between the two groups （P=0.362,0.986,0.373,0.584,0.931 ）, but CT value of the ascending aorta, RSPV, RIPV, LSPV and LIPV were lower in experimental group than in control group （P=0.000,0.001,0.000,0.003,0.000）. Scores of image quality were better in experimental group than in control group0（x^2=12.25 ,P=0.016;X^2=7.53 ,P=0.023）. Both the contrast agents（24 ml vs. 50 ml） and radi- ation dose[（5.27 ± 1.94） mSv vs. （7.30 ± 2.73） mSv] were lower in experimental group than in control group（P=0.011）. The scanning time was significantly shorter in experimental group than in control group[（0.94±0.07） s vs. （4.71 ± 0.37） s,P=0.000）]. Conclusion：CTPA with flash spiral mode and time-density curve could col- lect the satisfied image, reduce patients＇ contrast agents and radiation dose, and decrease the breathless time.