多排螺旋CT薄层重组和高分辨率CT靶扫对肺微小结节的价值比较

Evaluation of Pulmonary Micro-Nodules:A Comparison of Thin-Section MSCT and HRCT Target Scanning

目的评价多排螺旋CT(MSCT)薄层重组和高分辨率CT(HRCT)靶扫对肺微小结节(<10 mm)的显示效果和辐射剂量。方法回顾性分析100例微小肺结节MSCT薄层重组和HRCT靶扫的CT表现,包括结节的大小、密度、内部结构(空泡、钙化)、形态(边缘、"分叶"征、"毛刺"征)、伴随征象(支气管、血管、胸膜改变)。评价两种方法对上述征象的显示效果,并对辐射剂量进行比较。结果 MSCT薄层重组能准确地显示肺微小结节的密度、边缘、空泡、钙化、"分叶"、"毛刺"、胸膜改变,和HRCT靶扫有良好的一致性。两种方法对结节的均匀度、肿瘤微血管征、结节与小支气管关系的检出差异具有统计学意义(P<0.05)。MSCT薄层重组对均匀度倾向于更"均匀",肿瘤微血管征分型偏低,微血管的数量偏少。MSCT薄层重组容积CT剂量指数(CTDIvol)低于HRCT靶扫,两者之比约1∶2,重组剂量长度乘积(DLP)和有效剂量高于HRCT靶扫,两者之比约2∶1。结论 MSCT薄层重组可准确判断微小结节的多数征象,和HRCT靶扫有良好的一致性,避免再次HRCT扫描可有效降低辐射剂量。HRCT靶扫对结节的均匀度、肿瘤微血管征分型及血管数量、结节与小支气管关系的显示优于MSCT薄层重组。

Objective To evaluate the performance and radiation dosage of thin-slice reconstruction of MSCT and HRCT target scanning on pulmonary micronodules（diameter less than 10 mm）. Methods The CT appearances of thinslice reconstruction of MSCT and HRCT target scanning in 100 pulmonary micronodules were retrospectively analyzed. The size of nodules,density,internal structure（vacuolization,calcification）,peripheral structure（margin shape,lobulation andspiculation signs）,accompanying signs（ bronchial,vascular,pleural changes） were recorded. To evaluate the effect of the two methods on the imaging signs stated above,and to compare the radiation dosage. Results Thin-slice reconstruction of MSCT could accurately display the density,margin shape,vacuolization,calcification,lobulation and spiculation signs of pulmonary nodules as well as the pleural changes,and had good consistency with HRCT target scanning. There was significant difference between the two methods in the homogeneity of the nodules,the tumor microvessel sign and the relationship between the nodules and the small bronchus（ P〈0. 05）. The thin-section MSCT tended to be more homogenous,and the typing of microvessels was low and there were less microvessels. The CT dose index volume（ CTDIvol） of MSCT thin-section was lower than that of HRCT target scanning,the ratio was about 1 ∶ 2. The dose length product（ DLP） and the effective dose was higher than that of HRCT target scanning,the ratio was about 2∶ 1. Conclusion The thin-section MSCT can accurately detect most imaging signs of the pulmonary micronodules and can be favored over HRCT target scanning. Substitution of HRCT scan can effectively reduce the radiation dose. The HRCT target scanning is superior to thin-section MSCT in detecting the homogeneity of nodules,the tumor microvessel sign,vascular quantity,and the relationship between the nodules and the small bronchus.