外伤儿童颅脑CT螺距和探测器排数选择研究

Selection of CT pitch and detector row in traumatic children

目的:分析螺距和探测器排数的选择对外伤儿童颅脑CT扫描的图像质量和患儿接受的辐射剂量的影响,从而选择合适的组合减少患儿在颅脑CT扫描中的辐射剂量。方法:选取2018年4—8月在某院行CT扫描的颅脑外伤患儿71例,随机分为A、B、C 3组,其中A组20例,扫描时螺距为0.2,探测器排数为64排;B组26例,扫描时螺距为0.2,探测器排数为32排;C组25例,扫描时螺距为0.4,探测器排数为64排。对所得图像进行主观及客观分析,并采用SPSS 20.0软件对扫描时间、剂量长度乘积(dose length product,DLP)和有效剂量(effective dose,ED)进行比较分析。结果:3组图像的主观评分和信噪比差异均无统计学意义(P>0.05);探测器排数为64排时,C组的扫描时间、DLP、ED分别比A组减少约48.8%、8.3%和8.6%,差异均具有统计学意义(P<0.05);螺距为0.2时,A组扫描时间、DLP、ED分别比B组减少约42.2%、13.8%和13.9%,差异均具有统计学意义(P<0.05)。结论:对于颅脑外伤患儿,在进行螺旋CT扫描时,选用大螺距、多探测器排数进行快速扫描,减少检查时间且不影响图像质量,而如需重点观察颅底等特殊部位时,选用小螺距、多探测器排数进行扫描,以获得更加优质的图像质量。

Objective To investigate the influences of different pitches and detector rows on the image quality of craniocerebral CT scan of injured children and the radiation dose received by children so as to choose the appropriate combination to reduce the radiation dose of children in craniocerebral CT scan.Methods A total of 71 children with craniocerebral trauma undergoing CT scanning in some hospital from April to August 2018 were selected and randomly divided into three groups:A,B and C.There were 20 cases in group A with the pitch being 0.2 and detector row being 64;there were 26 cases in group B with the pitch being 0.2 and detector row being 32;there were 25 cases in group C with the pitch being 0.4 and detector row being 64.SPSS 20.0 was used for comparative analysis on scanning time,dose length value(DLP)and effective dose(ED)value.Results There were no statistical differences in subjective score and signal-to-noise ratio in the three groups(P>0.05);group C had the scanning time,DLP and ED significantly lower than those of group A by 48.8%,8.3%and 8.6%(P<0.05)in case the detector row was 64;group A had the scanning time,DLP and ED statistically lower than those of group B by 42.2%,13.8%,13.9%(P<0.05)in case the pitch was 0.2.Conclusion For the children with craniocerebral trauma,examination time can be shortened with non-affected image quality in case of large pitch and multi detector rows,while short pitch and multi rows prove to be appropriate for scanning special site such as skull base so as to obtain high-quality image.[Chinese Medical Equipment Journal,2019,40(11):38-41]