可变螺距技术在主动脉血管成像中的应用价值  

Application Value of Variable Pitch Technique in Aortic Vascular Imaging

作　　者：徐凯[1] 杜瑶 梁继祥[1] 王沄[1] 吴巧玲 孔令燕[1] 付海鸿 金征宇[1] XU Kai;DU Yao;LIANG Jixiang;WANG Yun;WU Qiaoling;KONG Lingyan;FU Haihong;JIN Zhengyu(Department of Radiology,Chinese Academy of Medical Sciences&Peking Union Medical College,Beijing 100730,China)

机构地区：[1]中国医学科学院/北京协和医学院放射科,北京100730

出　　处：《中国医疗设备》2021年第9期95-99,共5页China Medical Devices

摘　　要：目的评价佳能Genesis640层CT可变螺距技术在使用心电门控的主动脉血管扫描中的应用价值。方法将临床上行主动脉CTA检查的患者采用简单随机分组的方法分为两组:组1(n=31):采用可变螺距技术进行扫描,根据部位需要进行三段螺距以及心电门控状态切换。第一段:胸廓开口-气管分叉,螺距HP 91,心电门控关闭;第二段:气管分叉-心底,根据心率选择自动最佳螺距,心电门控开启;第三段:心底-耻骨联合上缘,螺距HP 91,心电门控关闭;组2(n=31)采用常规螺旋扫描,根据心率自动选择最佳螺距,心电门控全程开启。两组患者按照体质量静脉注射对比剂,均采用浓度为370 mgI/L的对比剂,组1对比剂按照体质量0.8 mL/kg注射,注射速度为4 mL/s,后续注射生理盐水40 mL,注射速度4 mL/s。组2对比剂注射速度4 mL/s,按照体质量1 mL/kg注射,后续注射生理盐水40 mL,注射速度4 mL/s。两组患者扫描均采用自动团注跟踪触发技术,选取气管分叉层面的降主动脉部放置感兴趣区(Region of Interest,ROI),ROI内平均CT值达到180 HU时自动触发扫描。计算并对两组患者主动脉扫描的辐射剂量(Radiation Dose,DLP)、有效剂量(Effective Dose,ED)、图像信噪比(Signal to Noise Ratio,SNR)、对比噪声比(Contrast Noise Ratio,CNR)进行客观评价,对图像质量进行主观评价。结果组1扫描ED(10.09±4.48)mSv,较组2的(17.34±7.45)mSv降低了42%(t=-4.638,P<0.001)。两组患者在主动脉各部位(升主动脉、主动脉弓、腹主动脉起始部及腹主动脉分叉部位)以及肾动脉的强化值、噪声、SNR、CNR均无统计学差异(P均>0.05)。两组图像主观评价差异也无统计学意义。结论带心电门控技术的主动脉CTA扫描中,可变螺距技术的应用较常规扫描能够在保证图像质量的同时,显著降低辐射剂量和对比剂使用量。Objective To evaluate the application of Canon Genesis 640 slice CT variable pitch technique in ECG gated aorta vascular imaging scans.Methods Patients undergoing aortic CTA were randomly divided into two groups using simple randomization method:group 1(n=31):scanning using the variable pitch technique,switchover of the three sections of pitch and the state of ECG gating were done based on the need of different body parts.The first section:thoracic opening-tracheal bifurcation,pitch HP 91,ECG-gating off.The second section:tracheal bifurcation-cardiac base,choose best pitch automatically according to heart rate,ECGgating on.The third section:cardiac base-on the pubic symphysis,pitch HP 91,ECG-gating off.In group 2(n=31),the conventional spiral scan was used and best pitch was automatically selected according to the heart rate,with ECG-gating on.Two groups of patients according to quality vein group lived 370 mgI/L Patients in both groups were intravenously injected with contrast agent at the concentration of 370 mgI/L according to body mass.Group 1 was injected with contrast agent at 0.8 mL/kg according to body mass at the injection rate of 4 mL/s,followed by 40 mL normal saline at the injection rate of 4 mL/s.In group 2,contrast agent was injected at a rate of 4 mL/s according to the body mass of 1 mL/kg,followed by injection of 40 mL normal saline at a rate of 4 mL/s.Automatic injection tracking trigger technique was used in both groups.The descending aorta of tracheal bifurcated layer was selected to place the region of interest(ROI),and the scan was automatically triggered when the mean CT value in ROI reached 180 HU.The dose length product(DLP),effective dose(ED),image signal-to-noise ratio(SNR)and contrast noise ratio(CNR)of aortic vascular scan were calculated and evaluated objectively in both groups,and the image quality was evaluated subjective.Results Group 1 scanning ED was(10.09±4.48)mSv,which decreased by 42%compared with group 2(17.34±7.45)mSv(t=4.638,P<0.001).There were no statistical differences

关 键 词：可变螺距技术 CT血管成像 辐射剂量 图像质量 

分 类 号：R445.3[医药卫生—影像医学与核医学]