低剂量多层螺旋CT扫描在强直性脊柱炎骶髂关节病变中的应用

Low dose multi-slice spiral CT scanning in sacroiliac joint with ankylos-ing spondylitis

目的探讨低剂量多层螺旋CT扫描在强直性脊柱炎骶髂关节病变中的可行性。方法选取临床怀疑强直性脊柱炎骶髂关节病变的患者99例随机分为3组。其他扫描条件不变,各组分别采用200mA、80mA、40mA管电流进行扫描。记录容积CT剂量指数(CTDI_(vol))和剂量长度乘积(DLP)。两位医师采用双盲法对图像质量进行评估。统计方法采用方差分析和x^2检验。结果 80mA组的图像质量与常规管电流组均可满足诊断要求,两者无显著性差异(P>0.05),但80mA组的CTDI_(vol)仅为常规管电流组的40%,DLP明显下降(P<0.05)。40mA组的图像质量不能满足诊断要求,与常规管电流组比较,两者有显著性差异(P<0.05)。结论强直性脊柱炎骶髂关节病变的低剂量CT扫描可满足临床诊断要求,值得推广。

Objective To evaluate the feasibility of low dose multi-slice spiral CT （MSCT） scanning in ankylosing spondylitis patients with sacroiliac lesions. Methods Ninety-nine patients suspicion of ankylosing spondylitis were examined with MSCT. These cases were randomly divided into three different tube current set groups （200 mA, 80 mA and 40 mA）, and the other scan parameters were the same. The weighted volume CT dose index （CTDIvol） and dose length product （DLP） were recorded. The image quality was assessed by two radiologists with double-blind method. The results were analyzed by Chi-square test and Variance test. Results The image quality in 80 mA group and conventional tube current set （200 mA） group can meet the diagnos- tic requirements, there was no significant difference between the two groups （P 〉 0.05）. However, CTDIvi in 80 mA group was only 40% of conventional tube current group, and DLP decreased significantly （P 〈 0.05）. The image quality in 40 mA group can not meet the diagnostic requirements, compared with the conventional tube current set group, there was a significant difference between the two groups in image quality （P 〈 0.05）. Conclusion The low dose CT scans in ankylosing spondylitis patients satisfy clinical diagnostic demand, and its clinical application is valuable.