MSCT下肢动脉血管成像扫描方案优化

目的探讨128层螺旋CT下肢CTA的最佳扫描方案。方法将60例接受下肢动脉CTA检查的患者随机均分成6组,优化组管电流300mA,层厚0.625mm,对比剂流率4ml/s,注射剂量100ml;其余各组只变动其中1个扫描参数,其他参数同优化组。高毫安组管电流为400mA,低毫安组管电流为200mA,大层厚组层厚为5mm,多对比剂组对比剂注射剂量为130ml,高流率组对比剂流率为4.5ml/s。记录扫描延迟时间;测量腹主动脉水平、股深浅动脉分叉水平、胫前后动脉上段水平、足背动脉水平的CT值;评价各组图像质量,并与优化组进行对比。结果优化组与高毫安组、多对比剂组、高流率组图像质量差异均无统计学意义(P均>0.05);优化组与低毫安组、大层厚组间图像质量差异均有统计学意义(P均<0.05)。结论应用128层螺旋CT机行下肢CTA扫描,采用管电流300mAs、层厚0.625mm、对比剂流率4ml/s、注射剂量100ml时图像质量优良率高,能够满足诊断要求。

Optimization of MSCT scanning program in lower extremity arterial angiography

Objective To optimize the scanning program of lower extremity arterial angiography with 128 spiral CT. Methods Totally 60 patients who underwent lower extremity MSCTA were divided into 6 groups randomly (each n=10), i.e. optimized group, high milliampere group, low milliampere group, large thickness group, multi-contrast agent group and high injection flow rate group, respectively. The scanning parameters of optimized group were tube current 300 mAs, thickness 0.625 mm, contrast agent injection flow rate 4 ml/s, contrast agent 100 ml, while in each of the other groups took only one parameter as variable, the tube current of high milliampere group and low milliampere group were 400 mAs and 200 mAs, respectively, thickness of large thickness group was 5 mm, contrast agent of multi-contrast agent group was 130 ml and injection flow rate of high injection flow rate group was 4.5 ml/s. CT value of abdominal aorta, femoral artery bifurcation, tibial artery, dorsalis pedis artery and delay time were recorded. The image quality was evaluated in each group, and then compared with optimized group. Results There was no statistically significant difference of image quality among optimized group and high milliampere group, multi-contrast agent group, high injection flow rate group, respectively (all P>0.05), while statistically significant differences of image quality were found among optimized group, low milliampere group and large thickness group (both P<0.05). Conclusion For lower extremity arterial angiography with 128 spiral CT, tube current 300 mAs, thickness 0.625 mm, contrast agent injection flow rate 4 ml/s, the injected dose at 100 ml are optimal for image quality and diagnostic requirements.