双源CT Flash双低技术手动触发扫描在冠状动脉CTA的可行性研究

A Feasibility Study on Coronary Angiography with Flash Technique of Dual-source Computed Tomography by Double Low Technical and Manual Trigger Scanning

目的:对比常规前瞻性心电触发扫描及对比剂用量方案,探讨在双源CT Flash扫描模式下,低k V、低对比剂用量、手动触发扫描方案在低体重、低心率患者行冠脉CTA检查的可行性。方法:48例患者分为两组:A组:24例,体重<65kg,45次/min≤心率≤65次/min,对比剂流速和用量分别为5.0 m L/s和20 m L(350 mg I/m L),行Flash扫描,管电压采用70 k V;B组:24例,体重<65 kg,48次/min≤心率≤65次/min,对比剂流速和剂量分别为5.0 m L/s和50 m L(350 mg I/m L),行前瞻性心电触发扫描,管电压采用100k V。对原始数据进行SAFIRE迭代重建。比较两组患者的性别、年龄、心率、体重、BMI、CTDIVOL、DLP和ED,测量并比较两组图像主动脉根部、左主干、冠脉三大支近段管腔内的CT值、噪声、信噪比及主动脉根部的对比噪声比。两组冠脉图像质量采用4级评分法进行比较。结果:两组患者在性别、年龄、心率、体重、BMI及两组图像主动脉根部、左主干、冠脉三大支近段的CT值、噪声、信噪比、主动脉根部对比噪声比无显著性差异(P>0.05),在CTDIVOL、DLP和ED方面两组图像有显著性差异(P<0.05)。两组冠脉图像质量等级无显著性差异,冠脉可评价节段率均>96%。结论:双源CT在低体重、低心率患者应用70 k V超低管电压和低对比剂用量的方案进行冠状动脉CTA检查可以获得满足临床诊断的图像质量,较常规方案的放射剂量和对比剂用量显著减低。

Objective： To investigate the application of low tube voltage, low-volume contrast media and manual trigger scanfor coronary artery CT angiography with Flash scan modeon dual-source CT equipment about patients with low weight and low heart rate, through contrast with prospectively ECG-triggering sequentia and normal-volume contrast media. Methods： 48 patients were scanned with a prospectively ECG-triggering sequential or Flash CCTA protocol on DSCT. All patients were divided into two groups： the weight and heart ratein Group A was less then 65kg and 65 beats per min, the injection rate and volume of contrast in Group A was 5.0 mL/s and 20mL （350 mg I/mL）, scanned with Flash scan mode, Tube voltage was 70 kV; the weight in Group B was less than 65 kg, the heart ratein in Group B was less than 65 beats per min, the injection rate and volume of contrastin in Group B was 5.0 mL/s and 50 mL （350 mg I/mL）, scanned with a prospectively ECG-triggering sequential, Tube voltage was 100kV. The raw data were reconstructed with sinogram affirmed iterative reconstruction （SAFIRE） technique. The differences of sex, age, FIR, weight, BMI, CTDIvoL, DLP and ED were compared. Besides, the CT value, noise, signal-to-noise ratio （SNR）and contrast-to-noise ratio （CNR） between the two Groups of the aortic root, left main coronary artery and the proximalsegment of each coronary arteries were compared. And Image quality （ Ⅰ -Ⅳ） between the two Groups was compared. Results： There were no significant differences in sex, age, HR, weight and BMI between the two Groups （all P〉 0.05）, while there were no significant differences in the CT value, noise, SNR and CNR of the aortic root, left main coronary artery and the proximalsegment of each coronary arteries between the two groups （all P 〉 0.05）. The CTDIvoL, DLP and ED in Group B was higher than Group A （all P 〉 0.05）. The scores of image quality showed no significant difference between the two Groups. They more than 96%. Conclusion： For patients with low weight and low heart rate, the use of tube voltage as 70kV and low-volume contrast media in DSCT is feasible. The radiation dose and contrastdosage can be much lower.