64层螺旋CT低剂量扫描诊断新生儿缺血缺氧性脑病的可行性

目的研究64层螺旋CT低剂量扫描在新生儿缺血缺氧性脑病（HIE）诊断中的可行性。方法选取临床拟诊HIE行CT检查的新生儿200例,随机等分成2组,分别使用120 kV,200 mAs及120 kV,75 mAs各扫描100例。分别比较2组CT权重剂量指数（CTDI）、剂量长度乘积（DLP）及总剂量（TDV）数值。两种扫描参数所得图像,由2名副高以上职称医师采用双盲法评价CT图像,分为优、良、合格和不合格,将优、良和合格归入符合诊断要求病例,并作统计学处理。结果在新生儿缺血缺氧性脑病的诊断中,64层螺旋CT低剂量组扫描的辐射剂量为常规组扫描辐射剂量的37.5%,两组符合诊断要求的影像质量差异无统计学意义（P〉0.05）。结论 120 kV,75 mAs低剂量扫描适用于新生儿缺血缺氧性脑病的CT检查,这也符合国际原子能机构（IAEA）倡导的将辐射照射减至可合理达到的最低水平的原则。

Feasibility of 64-slice spiral CT scans with low dose in diagnosing hypoxic-ischemic encephalopathy of the neonates

Objective To study the feasibility of 64-slice spiral CT scans with low dose in diagnosing hypoxic-ischemic encephalopathy（HIE） of the neonates.Methods 200 cases of HIE were randomly divided into routine dose（120 kV,200 mAs） group（n=100） and low dose（120 kV,75 mAs） group（n=100） according to the scanning conditions.The CT weighted dose index（CTDI）,dose length product（DLP） and total dose value（TDV） between two groups were separately calculated and compared.The imaging quality acquired from above two scan conditions were respectively categorized into following four grades： excellent,good,acceptable and unacceptable by two experienced radiologists using double blind mode.Except unacceptable,the previous three grades were considered to be achieved to the diagnostic requirement.The imaging quality between two groups was statistically analyzed and compared.Results In the diagnosis of neonatal HIE with 64-slice spiral CT,the radiation dose received by neonates low dose group of only achieved to 37.5% of routine dose neonates.The imaging guality between two groups which corresponded to the diagnostic requirement was not significant difference（P0.05）.Conclusion As for diagnosis of neonatal HIE,low dose CT scan is feasible and it is corresponding to the principle to reducing exposure to as low as reasonably achievable（ALARA） recommended by International Atomic Energy Agence（IAEA）.