初步评估低剂量胸部CT在肋骨骨折诊断中的价值

 目的  初步探讨低剂量胸部CT检查在肋骨骨折诊断中的应用价值。方法  在其他扫描参数一致的情况下,分别以噪声指数(noise index,NI)11和26对37例外伤患者进行两次扫描,记录每次CT检查的剂量长度乘积(dose length product,DLP)和有效剂量(effective dose,ED)。由两位放射科医师采用Bone Reading 软件和薄层横断位图像对扫描所见骨折情况进行诊断及Ⅰ、Ⅱ、Ⅲ、Ⅳ型的评估,以5分制对CT图像诊断的可接受率及主观噪声评分进行评价。采用χ2检验分析不同NI的图像对肋骨的诊断差异,采用Kappa分析评价不同观察者评定结果的一致性。结果   NI=11和NI=26时的ED分别为5.75±2.75和1.24±0.73;后者较前者DLP下降了78.4%;不同NI对诊断肋骨骨折之间的差异无统计学意义;两位医师的评定结果一致(Kappa值分别为0.931和0.905)。结论  采用合适的低剂量CT扫描技术可以用于肋骨骨折的诊断及评估。

Preliminary evaluation of the low dose thorax CT in the diagnosis for rib fractures

Objective  To preliminarily investigate the feasibility of low-dose thorax CT in the diagnosis of rib fractures.Methods  Using consistent scanning parameters,37 trauma patients were subjected to two thorax CT scans with noise index (NI) of 11 and 26.The dose length product (DLP) and effective dose (ED) were recorded for each scan.Diagnosis of fractures and evaluation of fracture type (Ⅰ,Ⅱ,Ⅲ and Ⅳ) were performed by two radiologists using Bone Reading software and thin-section axial CT images.A 5-point scale was employed for evaluating the acceptance rate of CT image diagnosis and the qualities of the images taken with different NI.The χ2 test was utilized to analyze the difference in the diagnosis of rib fractures using images taken with different NI.Kappa analysis was applied to investigate the consistency in fracture evaluation results between different radiologists.Results  The EDs were 5.75±2.75 and 1.24±0.73 when NI were 11 and 26,respectively.The DLP of the latter dropped 78.4% compared with that of the former.There was no significant difference in diagnosis of rib fracture between NI=11 and NI=26.The evaluation results given by the two radiologists were consistent (Kappa values were 0.931 and 0.905,respectively).Conclusions  An appropriate low-dose CT scan technique is suitable for the diagnosis and evaluation of rib fracture.