多层螺旋CT最大密度投影对肺微小结节的诊断价值

THE DIAGNOSTIC VALUE OF MAXIMUM INTENSITY PROJECTION CT SCANS FOR MICRONODULES OF THE LUNGS

目的通过与常规螺旋CT和薄层CT比较,评价最大密度投影(MIP)对肺弥漫性微小结节的诊断价值。方法对31例经常规螺旋CT或临床检查怀疑有肺微小结节浸润的病人,行多层螺旋CT平扫,利用原始数据进行薄层重建和多层厚多方位MIP重建,比较各种重建图像对微小结节的显示情况。结果6种图像中,3种MIP重建图像对结节的显示最好,5mm和10mm层厚MIP对微小结节的显示显著优于常规5和10mmCT和1.25mm薄层CT(χ2=4.20～9.20,P<0.05)。冠状位10mm与横轴位10mmMIP之间差异无显著意义(χ2=1.33,P>0.05)。结论多层螺旋CT的MIP重建图像对肺部微小结节的显示优于常规CT和薄层CT,它不仅能明确显示结节的存在,还可更为准确地显示结节的分布特点。冠状位重建可作为横轴位的补充。

Objective To evaluate the diagnostic value of maximum intensity projection （MIP） images for diffuse mi cronodules of the lung by comparing slice CT and conventional spiral CT. Methods Thirty-one patients who were suspected to have diffuse small nodules were scanned. The original data were used to reconstruct different thickness and orientation MIP image and 1.25 mm slice image. The result of different images was compared. Results Three kinds of MIP images were best in showing the presence of small nodules and their distribution characteristics. The results indicated that 5mm and 10 mm thick MIP were superior to conventional spiral 5 mm-,10 mm-,and 1.25 mm thick CT （Х^2=4.20-9.20, P〈0. 05） in showing the presence of small nodules. There was no remarkable difference between coronal and axis position （Х^2= 1.33,P〉0.05）. Conclusion MIP reconstruction is superior to conventional spiral CT and l. 25 mm-slice CT in showing not only the existence of diffuse small nodules in the lung but also more accurate in showing their distribution character. Coronal image may be used as a complement for axis image.