基于CT三维重建提取中心曲线测量喉气管狭窄的研究

Measuring laryngotracheal stenosis by extracting centerline based on CT 3D reconstruction

目的比较基于CT三维重建提取的中心曲线与常规CT三维重建在测量喉气管狭窄长度和严重程度上的准确性。方法回顾性分析2006年3月至2016年3月就诊于广西医科大学第一附属医院耳鼻咽喉头颈外科的35例喉气管狭窄患者(包括非气管切开19例、气管切开16例),其中男性20例,女性15例;年龄1~73岁,中位年龄40.5岁;以及同期纳入的20名正常人的CT资料,其中男性10例,女性10例;年龄20~63岁,中位年龄37.0岁。利用Mimics中心曲线测量方法,获取垂直于中心曲线的管腔全段连续截面面积,与常规CT三维重建方法测量的甲状软骨上切迹、声门等平面的间断截面面积进行比较;比较两种测量方法在颈段气管长度、喉气管狭窄长度以及气道最小面积等参数的测量差异;采用多因素线性逐步回归法分析两种测量方法评估喉气管狭窄程度差异的影响因素。选取其中3例喉气管狭窄患者,将测量的狭窄长度与手术标本相比较,以评价两种测量方法的准确性。采用SPSS 26.0软件进行统计学分析,以P<0.05为差异有统计学意义。结果正常人中,与常规CT三维重建方法相比,Mimics中心曲线法测量的甲状软骨切迹、声门、甲状软骨下缘、环状软骨下缘、胸骨上切迹平面的截面面积更小(t_(甲状软骨切迹)=4.685、t_(声门)=3.791、t_(甲状软骨下缘)=5.621、t_(环状软骨下缘)=6.312、t_(胸骨上切迹)=6.436,P值均<0.05),甲状软骨下缘至胸骨上切迹的气道长度更长(t=9.79,P<0.001)。在喉气管狭窄患者中,非气管切开组,用Mimics中心曲线法测量的最小气道面积比常规CT三维重建方法测量的面积更小,狭窄长度更长(t_(最小气道面积)=2.562、t_(狭窄长度)=5.240,P值均<0.05)。气管切开组中,用Mimics中心曲线法测量的狭窄长度比常规CT三维重建方法测量的长度更长(t=2.854,P<0.05)。多因素线性回归分析显示:不同CT层厚对两种方法测量狭窄长度差异的影响有统计学意义(b=-5.370,t=-3.306,P=0.004),不同气管前倾角度对两种方法测量最小气道面积差异的影响有统计学意义(b=-0.419,t=-2.208,P=0.040)。对比术中标本,Mimics测量长度与标本差值不足0.5 mm。结论基于CT三维重建提取的中心曲线法能精确地反映喉气管形态,可以更精准地测量喉气管狭窄的长度和严重程度。

Objective To compare the accuracy of the centerline extracted based on CT 3D reconstruction and conventional CT 3D reconstruction in measuring the length and degree of laryngotracheal stenosis.Methods A retrospective analysis was performed on 35 patients with laryngotracheal stenosis(including 19 cases without tracheotomy and 16 cases with tracheotomy)treated in the Department of Otorhinolaryngology Head and Neck Surgery of the First Affiliated Hospital of Guangxi Medical University from March 2006 to March 2016,including 20 males and 15 females,whose ages ranged from 1 to 73 years,with a median age of 40.5 years.And CT data of 20 normal subjects were included in the same period,including 10 males and 10 females,whose ages ranged from 20 to 63 years,with a median age of 37.0 years.The continuous cross-sectional area of the airway perpendicular to the centerline was obtained by Mimics software.The area was compared with the discontinuous cross-sectional areas reconstructed by conventional CT 3D reconstruction software advantage workstation,also the length of cervical trachea,the length of stenosis,and the minimum airway area were compared.Multi-factor linear stepwise regression method was used to analyze the factors influencing the measuring difference between the two methods.Three patients with laryngotracheal stenosis were selected,and the measured stenosis length was compared with the surgical specimens to evaluate the accuracy of the two methods.SPSS 26.0 software was used for statistical analysis.Results In normal people,the areas of thyroid cartilage notch,glottis,inferio thyroid cartilage margin,inferio cricoid cartilage margin,and suprasternal notch planes measured by Mimics centerline method were smaller than those measured by conventional CT 3D reconstruction(t_(thyroid cartilage notch)=4.685,t_(glottis)=3.791,t_(lower thyroid cartilage margin)=5.621,t_(lower cricoid cartilage margin)=6.312,t_(suprasternal notch plane)=6.436,P<0.05).And the airway length measured by Mimics centerline method from the inferior thyroid cartilage to the superior sternal notch was longer(t=9.79,P<0.001).In laryngotracheal stenosis,in the non-tracheotomy group,the minimum airway area measured by Mimics centerline method was smaller and the stenosis length was longer than those measured by the conventional CT 3D reconstruction,and the difference was statistically significant(t_(minimum airway area)=2.562,t_(stenosis length)=5.240,P<0.05).In the tracheotomy group,the stenosis length measured by Mimics centerline method was longer than that measured by conventional CT 3D reconstruction,and the difference was statistically significant(t_(stenosis length)=2.854,P<0.05).Multi-factor linear regression analysis showed that different CT thickness had a statistically significant effect on the difference in the length of stenosis measured by the two methods(b=-5.370,t=-3.306,P=0.004),and different tracheal forward angle had a statistically significant effect on the difference in the minimum airway area measured by the two methods(b=-0.419,t=-2.208,P=0.04).The difference between the measured length of the Mimics centerline method and the intraoperative specimens was less than 0.5 mm.Conclusion The centerline extracted based on CT 3D reconstruction can precisely reflect the laryngotracheal morphology and measure laryngotracheal stenosis more accurately.