6层螺旋CT低剂量容积扫描多平面重组在儿童副鼻窦检查中的应用研究

The application of 6-slice spiral CT low dose volume scanning and multiple planar reconstruction in paranasal sinusitis of children

目的探讨6层螺旋CT低剂量容积扫描多平面重组在儿童副鼻窦检查中的可行性。方法选取100例临床疑似副鼻窦疾病儿童随机分为A、B、C、D 4组,其他扫描条件不变,A组采用150 mAs常规剂量、B组采用75 mAs低剂量、C组采用50 mAs低剂量、D组采用35 mAs低剂量行副鼻窦横断位容积扫描并多平面重组。比较4组扫描的容积CT剂量指数（CTDIvol）和剂量长度乘积（DLP）,并由3名高年资医师对CT图像质量进行盲式评价。统计方法采用方差分析和χ-2检验。结果低剂量B组、C组的图像质量与常规剂量A组均可满足诊断要求,B组、C组与A组比较差异无统计学意义（P〉0.05）,但B组、C组的CTDIvol分别仅为常规剂量A组的50.2%及33.3%,DLP明显下降（P〈0.05）,CTDIvol及DLP的下降以低剂量C组更为明显。低剂量D组的图像质量不能满足诊断要求,与常规剂量A组比较,两者差异有统计学意义（P〈0.05）。结论儿童副鼻窦低剂量螺旋CT容积扫描多平面重组有效地降低了照射剂量,同时又保证了图像质量满足诊断要求,适宜的扫描参数可以实现CT图像质量与降低照射剂量最优化结合,值得临床推广应用。

Objective To discuss the practicability of 6-slice spiral CT low dose volume scanning and multiple planar reconstruction（MPR） in the examination of paranasal sinusitis in children. Methods One-hundred children suspected to be paranasal sinusitis were randomly assigned to 4 groups（A,B,C,D）,followed by paranasal axial volume scanning and MPR,in which 150 mAs regular does was performed in group A,75 mAs（low does） was perfomed in group B,50 mAs（low dose）was performed in group C and 35 mAs（low does）was performed in group D. CT dose index volume（CTDIvol） and dose-length product（DLP） were compared in the 4 groups. The quality of CT images was evaluated by 3 senior radiologists using blind method. Analysis of Variance and χ-2test were used in statistical analysis.Results Both the image quality of low dose groups（B and C） and regular does group（A） reached the standard for diagnosis. No statistical differences were found between group B,C and group A（P〈0.05）. However,the CTDIvol of B and C were only 50.2% and 33.3% of regular dose group（A）,respectively. DLP also decreased significantly（P〈0.05）in low dose groups. The decreases of CTDIvol and DLP were more distinct in group C. The quality of images in group D did not reach the standard for diagnosis compared with group A（P〈0.05）. Conclusion The method of low dose volume CT scanning and multiple planar reconstruction effectively decreases the irradiation dose in the diagnosis of paranasal sinusitis in children. The image quality using this method also meets the standard for diagnosis. Proper scanning parameters could result in optimization of CT image quality and irradiation dose,which is worth for clinical use.