尘肺CT扫描方案的探讨

目的比较常规剂量CT、低剂量CT及高分辨率CT（HRCT）3种扫描方案对尘肺的诊断能力,以期确定最佳方案。方法 37例经专业机构确诊的尘肺患者均经常规剂量CT、低剂量CT及HRCT3种方案扫描。采用统计学方法分析与比较该3种方案对尘肺特征性表现,小阴影、大阴影及进行性团块状纤维化（PMF）及纤维化早期表现及合并症的检出率。结果 3种扫描方案对小阴影、大阴影及团块状纤维化（PMF）的检出例数相符,均为36例、20例及16例,而对于大、小阴影及PMF周围的瘢痕肺气肿、肺纹理扭曲等征象,以HRCT显示较清晰。HRCT对早期肺间质纤维化,诸如胸膜改变、小叶间隔增厚、小叶肺气肿及蜂窝状影的显示例数显著多于其他两组（P〈0.05）。除肺气肿外,3种方案对其他合并症肺结核、肺癌及呼吸系统感染等的检出率无明显差别。结论低剂量CT与常规剂量CT均可用于尘肺的普查与诊断,为减少受检者的辐射剂量,应尽可能采用低剂量CT扫描。而对于肺间质改变的观察,HRCT应作为首选方案。

Research on CT scan protocols of pneumoconiosis

Objective To compare the diagnostic capability of three CT scan protocols including conventional CT,low dose CT and high-resolution CT（HRCT） for pneumoconiosis so as to determine the optimal protocol.Methods Thirty-seven patients with pneumoconiosis confirmed by the occupational agency underwent above three protocol exammations.The detection rate of the three protocols for signs specific to pneumoconiosis（small shadow,large shadow and progressive massive fibrosis,PMF） and its early fibrosis as well as complications was statistically analyzed and compared.Results The positive rates of small shadow,large shadow and PMF were same in 3 different protocols,i.e.36,20 and 16 cases,respectively,while HRCT was superior to the other two protocols in showing scar emphysema and lung marking distortion around small shadow,large shadow and PMF.The positive rates of early pulmonary interstinum fibrosis such as pleural change,interlobular sept thicking,lobular emphysema and honeycombed shadows was also significantly superior to other protocols in HRCT（P0.05）.Except for emphysema,the detective rate of the three protocols for other complications including tuberculosis,lung cancer and respiratory tract infection was not statistically different.Conclusion Both low dose CT and conventional CT could be used for the screening and diagnosis of pneumoconiosis but low dose protocol should be adopted as more as possible in order to reduce the radiation dose received by the subjects,as for patients with early changes of pulmonary interstinum,HRCT should be recommended.