第3代双源CT大螺距冠状动脉CT血管成像中盐水冲洗速率对检查效果的影响

Effects of the Saline Flush on High-pitch CT Coronary Angiography on Third-generation Dual-source CT System

目的探究并优化在超低对比剂用量方案下,采用第3代双源CT大螺距扫描技术进行冠状动脉CT血管成像(CTA)检查时,不同盐水注射速率对该检查图像效果的影响。方法共前瞻性连续入组68例临床可疑或已确诊冠心病患者,均采用第3代双源CT进行前瞻性大螺距技术冠状动脉CTA扫描。采用自动管电压选择技术进行患者扫描电压值的智能选择,根据所选不同管电压值对应选择其对比剂注射方案,即70 kV的对比剂量和流速分别为18 ml和3.0 ml/s,80 kV的对比剂量和流速分别为21 ml和3.0 ml/s。然后将患者随机分为2组:A组(n=31):盐水追加方案为流速3.0 ml/s;B组(n=37):盐水追加方案为流速4.0 ml/s;A、B两组盐水总量均为40 ml。比较两组间的辐射剂量、客观图像质量和主观图像质量。结果两组患者的有效剂量(ED)差异无统计学意义[(0.36±0.12)m Sv比(0.37±0.13)m Sv;t=-0.40,P=0.70],所有患者的平均ED为(0.43±0.28)m Sv。A组右冠状动脉远段(76.04±62.46比43.96±26.94;t=2.67,P=0.01)和左回旋支近段(69.60±43.13比44.08±24.08;t=2.96,P=0.01)的对比噪声比均明显高于B组,其余参数两组间差异均无统计学意义(P均>0.05)。两组间的主观图像质量差异也无统计学意义(χ2=2.53,P=0.47)。结论采用超低剂量对比剂方案行第3代双源CT大螺距冠状动脉CTA检查时,使用与对比剂流速相同的盐水冲洗速率可获得更好的检查图像质量。

Objective To preliminarily investigate and optimize the saline flush effects to the image quality（ IQ） and effective scan rate of high-pitch CT coronary angiography（ CCTA） using ultra-low contrast media（ CM） protocols on third-generation dual-source CT（ DCST）. Methods Sixty-eight consecutive patients with suspected or known coronary artery disease（ CAD） were recruited and underwent prospective highpitch CCTA on third-generation DSCT with automatic tube voltage selection（ 70-80 kV） based ultra-low CM pro-tocols： 18 ml（ 3. 0 ml / s） for 70 kV and 21 ml（ 3. 0 ml / s） for 80 kV. All the patients were randomly divided in to two groups： Group A（ n = 31） with the saline flush of 3. 0 ml / s（ 40 ml） and Group B（ n = 37） with the saline flush of 4. 0 ml / s（ 40 ml）. The baseline data, risk factors, quantitative image quality（ IQ）, qualitative IQ results, and effective dose（ ED） were evaluated and compared. Results There was no significant difference in ED between two groups [（ 0. 36 ± 0. 12） m Sv vs.（ 0. 37 ± 0. 13） m Sv; t =- 0. 40, P = 0. 70].The average ED in all patients was（ 0. 43 ± 0. 28） m Sv. However, the contrast to noise ratio（ CNR） of right coronary artery distal segment in Group A was significantly higher than that in Group B（ 76. 04 ± 62. 46 vs.43. 96 ± 26. 94; t = 2. 67, P = 0. 01） and the CNR of left circumflex artery proximal segment in Group A was significantly higher than that in Group B（ 69. 60 ± 43. 13 vs. 44. 08 ± 24. 08; t = 2. 96, P = 0. 01）. No other significant difference was found in terms of baseline characteristics, and objective image quality（ all P〉0. 05）.Subjective IQ showed no significant difference between these two groups（ χ^2= 2. 53, P = 0. 47）. Conclusion Under high-pitch CCTA using ultra-low CM protocols [18-21 ml（ 3. 0 ml / s）] on third-generation DCST, the saline flush at a flow rate of 3. 0 ml / s can achieve satisfactory IQ and effective scan rate.