上气道螺旋CT三维重建技术及其临床应用价值

3D Reconstruction of the Upper Airway with Helical CTIts Technique and Clinical Applications

目的 探讨上气道的螺旋CT三维 ( 3D)重建技术及其临床应用价值。材料与方法 对 10例正常和 3 6例上气道病变的患者进行轴位螺旋CT扫描 ,层厚 3 .0mm ,正常组采用不同重建间隔、阈值作气道表面遮盖法 (SSD)重建 ,病变组分别作气道SSD、Ray Sum(表面透视法 )重建和叠加成像。结果 采用 1.0mm重建间隔、上限阈值为 -5 0 0HU能获得最佳的气道SSD图像 ;SSD图像能清楚显示上气道的正常形态 ,多方位观察可全景地反映气道表面受压的情况 ,RaySum能更好地显示狭窄内缘的情况 ,9例 ( 2 5 % )病变组气道SSD显示正常 ;SSD图像上显示的肿瘤侵犯范围明显小于轴位和多平面重建 (MPR)图像。叠加成像能清楚显示肿瘤与邻近结构尤其是血管、气道的关系。结论 3D重建能立体地显示上气道病变 ,是轴位和MPR图像的很好补充手段。

Objective To evaluate the technique and clinical application of helical CT 3D reconstruction for the upper airway.Materials and Methods Helical CT was performed with 3.0mm slice thickness and 1.0～1.2 pitch in 10 normal subjects and 36 patients with upper airway diseases. In the healthy group, the upper airway shaded surface display (SSD) was processed by using different reconstruction interval (1.0～3.0mm) and upper threshold (0～-900HU), while in the patient group, SSD, RaySum and integrated 3D images were made respectively.Results The optimal upper airway SSD image could be obtained by using reconstruction interval 1.0mm and upper threshold -500HU. SSD image could display the normal shape of the upper airway, and provide a panoramic view of the airway compression by lesion from multiple directions. RaySum could well demonstrate the internal margin of the narrowed airway, with the airway appearing normal in 9 (25%) cases. The extent involved by the tumor was significantly smaller on SSD images than that on axial or MPR images. The integrated 3D images could clearly demonstrate the relationship between the tumor and adjacent structures, such as vessels or airway.Conclusion Helical CT 3D reconstruction can provide a 3D image of upper airway diseases, thus, it is a useful complement to axial and MPR images.