多排螺旋CT低剂量扫描在成人颅脑检查中的应用价值

目的评价多层螺旋CT适用于成人颅脑检查的低剂量扫描条件。方法将500名健康成年人随机分成5组:第1组采用常规剂量,第2~5组分别采用低剂量(200、160、100、80mAs)扫描。采用双盲法对图像质量独自评分,分析扫描剂量与图像质量评分的关系;比较第2~5组的CT剂量指数(CTDI vol)和平均剂量长度乘积(DLP)值相对第1组下降的比例。结果图像质量评分一致性好(κ=0.860,P=0.017),扫描剂量与图像质量主观评分呈正相关(r=0.512,P<0.01),第1~4组图像质量差异无统计学意义(P>0.05),而第5组图像质量明显下降(P<0.05)。与第1组相比,第2~5组CTDI vol、DLP值均显著降低(P<0.05)。结论管电流为100mAs时,多层螺旋CT既能保证成人颅脑检查的图像质量,又能显著降低辐射剂量。

The Clinical Application of the Low-dose Multi-Slice spiral CT to Adult Cranial Examination

Objective To analyze the clinical application of low-dose multi-slice spiral CT to adult cranial examination. Methods A total of 500 healthy adults received multi-slice spiral CT in our hospital were divided into 5 groups, which were group Ⅰ（receiving conventional dose）, group Ⅱ（tube current was 200 mAs）, group Ⅲ（tube current was 160 mAs）, group Ⅳ（tube current was 100 mAs） and group Ⅴ（tube current was 80 mAs）. The image quality was solely determined by double blind method and the relationship of radiation dose and image quality was analyzed. The reduction ratios of computed tomographic dose index （CTDI vol） and the average dose length product （DLP） in group Ⅱ to Ⅴ were compared to group Ⅰ. Results The concordance of the scores of image quality was perfect（κ=0.860,P=0.017）. The positive relationship to radiation dose and image quality was confirmed. The image qualities of group Ⅰ to Ⅳ were no different （P〉0.05）, but the image quality of group Ⅴ was poor （P〈0.05）. Compared to group Ⅰ, the values of CTDI vol and DLP in group Ⅱ to Ⅴwere lower （P〈0.05）. Conclusion The multi-slice spiral CT which the value of tube current was 100mA could ensure the image quality and reduce the radiation dose to adult cranial examination.