儿童气管异物低剂量CT扫描及后处理图像诊断价值的分析

目的 探讨CT低剂量扫描及后处理图像质量对气管支气管异物的诊断价值。方法 对96例气道异物患儿行MSCT扫描,CT扫描参数为100kV,40～80mA,层厚5mm,间距5mm,螺距0.396,扫描后进行层厚0.625mm,间隔0.625mm重建,对获得的数据进行图像后处理,后处理技术包括多平面重建（MPR）、最小密度投影（MinIP）、CT仿真支气管内窥镜（CTVB）。并与支气管内窥镜结果进行比较。结果 96例气管支气管异物均获得满意的后处理图像,螺旋CT及后处理技术的诊断准确性为97.9%,异物定位与支气管镜检相符97.9%。其中MPR（包括CPR）及MinIP在显示异物本身和局限性气管、支气管阻塞最好。结论 小儿气管支气管异物可用螺旋CT低剂量扫描,但不能用单一的后处理技术,应该将轴位和多种后处理技术结合起来,综合分析。本病的直接征象是显示异物本身,而局限性支气管阻塞需结合其他征象才能确诊。

The value of CT low dose scan and post-processing techniques in tracheal foreign body of children

Objective To evaluate the values of low-dose CT scan and post-processing techniques in diagnosis of tracheal foreign body of children. Methods Ninty-six children with tracheal foreign bodies were scanned by 256-slice spiral CT scanned at 100 kV and 40~80 mA, slice thickness： 5 mm, increment 5 mm, pitch 0. 396, reconstructed at slice thickness 0. 625 mm, increment 0. 625 ram. All the data were post-procesed by workstation, post-processing techniques inciuding MPR, MinlP, CTVB, then compared with bronchoscopy. ResuLts All the post-processing imaging of 96 tracheal foreign body were satisfied, the diagnostic accuracy of spiral CT with post-processing techniques was 97.9 %, Coincidence rate of foreign body localization was 97.9% compared with bronchoscopy, MPR （including CPR） and MinlP were the best in displaying foreign body and limitations of the trachea, bronchial obstruction. Conclusion Low-dose CT scan can be used to diagnose tracheal foreign body of children, but should be comprehensive analysis using axial view and various post-process- ing techniques. The direct sign of this disease is foreign bodies, but the final diagnosis of limitations of the bronchial ob- struction needs to combine other signs.