螺距优化组合对胸腹部CTA图像质量与辐射剂量探讨

目的:探讨MSCT螺距对胸腹部CTA图像质量的影响,并比较辐射剂量。资料与方法:搜集临床拟诊为胸腹部血管病变的患者90例,按不同螺距随机分3组(n=30例):A组,螺距1.375:1、床速55mm/s;B组,螺距0.984:1、床速39.37mm/s;C组,螺距0.516:1、床速20.62mm/s;均采用相同的注射速率及对比剂量进行对比剂追踪触发扫描。获取数据后由影像主任医师和主管技师各一位在AW4.4工作站进行图像质量评价。结果:通过螺距优化后,A、B、C3组平均每位患者扫描时间分别为:(12.60±0.54)s、(17.40±0.44)s、(33.10±1.48)s。DLP分别为:(1462.50±71.56)mGy·cm、(2010.55±62.14)mGy·cm、(3821.58±198.50)mGy·cm。它们之间的差异具有明显的统计学意义(P<0.01)。3组的有效剂量(ED)分别为:24.96mSv、34.18mSv、64.97mSv。A组比B组的每位患者ED减少9.22mSv,降低了26.97%(9.22/34.18)。A组比C组的每位患者ED减少40.01mSv,明显降低了61.58%(40.01/64.97)。3组在胸主动脉、肾门水平腹主动脉、双侧髂外动脉末段平均CT值分别为:353.00Hu、350.77Hu、350.70Hu,3组间差异不具有统计学意义(P>0.05),重组血管清晰度及显示血管分支数亦无明显差异。结论:采用A组螺距优化、快的床速扫描参数可以明显地减少患者的辐射剂量,达到既保证图像质量又符合诊断要求。

Pitch Optimizing Combination of Thoracic and Abdominal CTA Image Quality and Radiation Dose Discussion

Objective:To evaluate the pitch of the thoracic and abdominal MSCT CTA image quality,and compare the radiation dose.Materials and Methods:Collection of clinical suspected thoracic and abdominal vascular lesions in 90 patients,according to the different pitch were randomly divided into 3 groups(n=30),group A:a pitch of 1.375:1,55 mm/s bed velocity;group B:a pitch of 0.984:1,39.37 mm/s bed velocity;group C:pitch,0. 516:1 bed velocity 20.62 mm/s,using the same injection rate and dose of contrast contrast tracking trigger scanning.After obtaining data from imaging director and supervisor technician in a AW4.4 workstation for image quality evaluation.Results:Through the pitch after optimization,A,B,C 3 groups average each patient scan time respectively:(12.60±0.54)s,(17.40±0.44)s,(33.10±1.48)s,DLP respectively:(1 462.50±71.56)mGy.cm, (2 010.55±62.14)mGy.cm,(3 821.58±198.50 the difference between mGy.cm),which was statistically significant(P<0.01);3 groups of effective dose(ED)were:24.96 mSv,34.18 mSv,64.97 mSv,A group than in B group for each ED9.22 reduction in patients with mSv,reduced by 26.97%(9.22/34.18),A group than in C group for each patients 40.01 ED by mSv,was significantly reduced by 61.58%(40.01/64.97).3 groups in the ascending aorta,abdominal aorta,renal hilar level of bilateral external iliac artery end average CT values were:353.00 Hu, 350.77 Hu,350.70 Hu,the difference between the 3 groups was not statistically significant(P>0.05), recombinant vascular definition and display of vascular branching number also no difference.Conclusion:The groups A pitch optimization,fast bed velocity scanning parameters can significantly reduce the patient radiation dose,so as to ensure the image quality and meet the requirements of diagnosis.