256层螺旋CT低管电压冠状动脉成像技术的应用研究

Application of 256-slice spiral CT coronary angiography in low tube voltage setting

目的探讨降低管电压对体质指数(BMI)在正常范围内的患者进行256层螺旋CT冠状动脉(CTA)检查的临床应用价值。方法将90例BMI在正常范围内并进行冠状动脉CTA检查的患者随机分成两组,A组50例,管电压采用120 k V,B组40例,管电压采用100 k V,采用回顾性心电门控扫描。分别对两组检查图像的血管强化程度、重建血管清晰度以及辐射剂量进行对比分析评价。结果 90例患者均成功完成检查。两组之间图像质量分级差异和图像信号噪声比差异均无统计学意义(P>0.05),B组冠状动脉腔内CT值均较A组增高(P<0.001),B组CT容积剂量指数(CTDIvol)、剂量长度乘积(DLP)和平均有效剂量(ED)较A组显著减低,有效剂量由(16.25±2.35)m Sv降至(7.89±0.67)m Sv,差异均有统计学意义(t=21.75,P<0.001)。结论对BMI在正常范围内的患者,冠状动脉CTA采用100KV检查,可明显降低辐射剂量,并获得满足临床诊断的冠状动脉图像。

Objective To evaluate the clinical application of low k V scanning in CT coronary angiography by256-slice spiral CT in patients with normal body mass index（BMI）. Methods Ninety patients with normal BMI undergoing 256-slice spiral CT coronary angiography were randomly divided into two groups： group A（50 patients） of conventional scanning tube voltage 120 k V and group B（40 patients） of tube voltage with 100 k V. Scanning was performed with retrospectively ECG-gated technique. Image quality, contrast noise ratio（CNR）, volume CT dose index（CTDIvol）,and effective dose（ED） of two groups were evaluated and compared. Results All the 90 patients were successfully inspected. There was no significant difference in the image quality score and the CNR between the two groups（P〈0.05）.The CT values of coronary in group B were significantly higher than those in group A（P〈0.001）. The average CTDIvol,DLP and the mean ED in group B were significantly reduced compared with group A（t=21.75, P〈0.001）, with the mean ED of（16.25±2.35） m Sv in group B and（7.89±0.67） m Sv in group A. Conclusion For patients with normal BMI, CT coronary angiography at 100 k V can significantly reduce the radiation dose and ensure image quality.