第3代双源CT70kV管电压和20～25ml对比剂模式下行头颈联合CT血管成像在体质量小于75kg人群中的效果

Third-generation Dual-source CT for Head and Neck CT Angiography with 70 kV Tube Voltage and 20-25 ml Contrast Medium in Patients With Body Weight Lower than 75 kg

目的观察第3代双源CT 70 kV管电压和20~25 ml对比剂模式下行头颈联合CT血管成像的效果,评估注射同侧对比剂滞留产生的静脉伪影对图像质量的影响。方法采用随机表格法将怀疑或已有头颈部动脉血管疾病、体质量小于75 kg行头颈第3代双源CT血管成像扫描的40例患者随机分为70 kV组和100 kV组,每组20例,70 kV组采用20~25 ml对比剂和高级模拟迭代重建技术;100 kV组采用40 ml对比剂和滤波反投影技术。采用3分法对对比剂滞留产生的静脉伪影及对比剂滞留范围进行主观评分。结果 70 kV组有效剂量较100 kV组下降约58%(t=-18.14,P<0.001)。70 kV组20例患者中,16例(80.0%)存在静脉伪影,其中6例(37.5%,6/16)的静脉伪影影响邻近动脉的评价;100 kV组20例患者中,19例(95.0%)存在静脉伪影,其中7例(36.8%,7/19)的静脉伪影影响邻近动脉的评价;两组间差异无统计学意义(Z=-0.878,P=0.380)。70 kV组20例患者中,13例(65.0%)对比剂滞留较明显,其中2例(15.3%,2/13)对比剂滞留延续至上腔静脉;100 kV组20例患者中,19例(95.0%)对比剂滞留较明显,其中13例(68.4%,13/19)对比剂滞留延续至上腔静脉;两组间差异有统计学意义(Z=-3.654,P<0.001)。结论第3代双源CT 70 kV管电压和20~25 ml对比剂模式下行头颈联合CT血管成像,较100 kV扫描辐射剂量明显下降,对比剂滞留范围明显减低,静脉伪影与100 kV组相近。

Objective To investigate the image quality of head and neck CT angiography（ CTA） using the third-generation dual-source CT combined with 70 kV tube voltage and 20-25 ml contrast medium（ CM）,and evaluate the effects of venous artifacts arising from the CM on the ipsilateral side of injection. Methods Totally 40 consecutive patients with suspected vascular diseases and body weight lower than 75 kg prospectively un-derwent head and neck CTA examination using the third-generation dual-source CT. CTA was performed with a third-generation dual-source CT system. Patients were randomly divived into 70 kV group（ n = 20） and 100 kV group（ n = 20）. The 70 kV group used 20-25 ml CM and advanced modeled iterative reconstruction technique,and the 100 kV group used 40 ml CM and filtered back projection. Venous artifacts and CM residues were evaluated by a 3-point scale（ 1 = excellent,3 = poor）, respectively. Results The effective dose of 70 kV group decreased 58 % compared to 100 kV group（ t =- 18. 14, P〈0. 001）. In the 70 kV group, 16 patients（80. 0%） presented with venous artifacts and six of them（37. 5%,6 /16） affected the adjacent arteries. In the 100 kV group,19 patients（ 95. 0 %） presented with venous artifacts, and seven of them（ 36. 8 %,7 /19）affected the adjacent arteries（ Z =- 0. 878, P = 0. 380）. In the 70 kV group,13 patients（ 65. 0 %） presented with obvious CM residues and two of them（ 15. 3 %,2 /13） prolonged into the superior vena cava（ SVC）.In the 100 kV group, 19 patients（ 95. 0 %） presented with obvious CM residues, and thirteen of them（68. 4%,13 /19） prolonged into the SVC（Z =- 3. 654,P〈0. 001）. Conclusion Compared with the 100 kV, the third-generation dual-source CT for head and neck CTA, combined with 70 kV and 20-25 ml CM, can remarkably decrease the radiation dose, along with reduced CM residues and comparable venous artifacts.