Abstract：
BACKGROUND: In patients with tracheobronchial involvement, the differential diagnosis between granulomatosis with polyangiitis (GPA) and relapsing polychondritis (RP) can be challenging. The aim of this study was to describe the characteristics of airway abnormalities on chest computed tomography (CT) in patients with GPA or RP and to determine whether specific imaging criteria could be used to differentiate them.
METHODS: GPA and RP patients with tracheobronchial involvement referred to a national referral center from 2008 to 2020 were evaluated. Their chest CT images were reviewed by two radiologists who were blinded to the final diagnosis in order to analyze the characteristics of airway involvement. The association between imaging features and a diagnosis of GPA rather than RP was analyzed using a generalized linear regression model.
RESULTS: Chest CTs from 26 GPA and 19 RP patients were analyzed. Involvement of the subglottic trachea (odds ratio for GPA=28.56 [95% CI: 3.17; 847.63]; P=0.001) and extensive airway involvement (odds ratio for GPA=0.02 [95% CI: 0.00; 0.43]; P=0.008) were the two independent CT features that differentiated GPA from RP in multivariate analysis. Tracheal thickening sparing the posterior membrane was significantly associated to RP (odds ratio for GPA=0.09 [95% CI: 0.02; 0.39]; P=0.003) but only in the univariate analysis and suffered from only moderate interobserver agreement (kappa=0.55). Tracheal calcifications were also associated with RP only in the univariate analysis (odds ratio for GPA=0.21 [95% CI: 0.05; 0.78]; P=0.045).
CONCLUSIONS: The presence of subglottic involvement and diffuse airway involvement are the two most relevant criteria in differentiating between GPA and RP on chest CT. Although generally considered to be a highly suggestive sign of RP, posterior tracheal membrane sparing is a nonspecific and an overly subjective sign.
METHODS: GPA and RP patients with tracheobronchial involvement referred to a national referral center from 2008 to 2020 were evaluated. Their chest CT images were reviewed by two radiologists who were blinded to the final diagnosis in order to analyze the characteristics of airway involvement. The association between imaging features and a diagnosis of GPA rather than RP was analyzed using a generalized linear regression model.
RESULTS: Chest CTs from 26 GPA and 19 RP patients were analyzed. Involvement of the subglottic trachea (odds ratio for GPA=28.56 [95% CI: 3.17; 847.63]; P=0.001) and extensive airway involvement (odds ratio for GPA=0.02 [95% CI: 0.00; 0.43]; P=0.008) were the two independent CT features that differentiated GPA from RP in multivariate analysis. Tracheal thickening sparing the posterior membrane was significantly associated to RP (odds ratio for GPA=0.09 [95% CI: 0.02; 0.39]; P=0.003) but only in the univariate analysis and suffered from only moderate interobserver agreement (kappa=0.55). Tracheal calcifications were also associated with RP only in the univariate analysis (odds ratio for GPA=0.21 [95% CI: 0.05; 0.78]; P=0.045).
CONCLUSIONS: The presence of subglottic involvement and diffuse airway involvement are the two most relevant criteria in differentiating between GPA and RP on chest CT. Although generally considered to be a highly suggestive sign of RP, posterior tracheal membrane sparing is a nonspecific and an overly subjective sign.
摘要：
背景：在气管支气管受累的患者中，肉芽肿性多血管炎(GPA)和复发性多软骨炎(RP)的鉴别诊断具有挑战性.这项研究的目的是描述GPA或RP患者胸部计算机断层扫描（CT）上气道异常的特征，并确定是否可以使用特定的成像标准来区分它们。
方法：评估了2008年至2020年转诊到国家转诊中心的气管支气管受累的GPA和RP患者。两名放射科医生对他们的胸部CT图像进行了回顾，他们对最终诊断一无所知，以分析气道受累的特征。使用广义线性回归模型分析了成像特征与GPA而非RP诊断之间的关联。
结果：分析26例GPA和19例RP患者的胸部CT。声门下气管受累(GPA比值比=28.56[95%CI:3.17;847.63];P=0.001)和广泛气道受累(GPA比值比=0.02[95%CI:0.00;0.43];P=0.008)是多变量分析中区分GPA和RP的两个独立CT特征。保留后膜的气管增厚与RP显着相关（GPA的比值比=0.09[95％CI：0.02;0.39];P=0.003），但仅在单变量分析中，并且仅具有中度观察者之间的一致性（kappa=0.55）。气管钙化也仅在单因素分析中与RP相关(GPA比值比=0.21[95%CI:0.05;0.78];P=0.045)。
结论：声门下受累和弥漫性气道受累是胸部CT上GPA和RP区分的两个最相关的标准。尽管通常被认为是RP的高度暗示性标志，气管后膜保留是一种非特异性且过于主观的体征。
方法：评估了2008年至2020年转诊到国家转诊中心的气管支气管受累的GPA和RP患者。两名放射科医生对他们的胸部CT图像进行了回顾，他们对最终诊断一无所知，以分析气道受累的特征。使用广义线性回归模型分析了成像特征与GPA而非RP诊断之间的关联。
结果：分析26例GPA和19例RP患者的胸部CT。声门下气管受累(GPA比值比=28.56[95%CI:3.17;847.63];P=0.001)和广泛气道受累(GPA比值比=0.02[95%CI:0.00;0.43];P=0.008)是多变量分析中区分GPA和RP的两个独立CT特征。保留后膜的气管增厚与RP显着相关（GPA的比值比=0.09[95％CI：0.02;0.39];P=0.003），但仅在单变量分析中，并且仅具有中度观察者之间的一致性（kappa=0.55）。气管钙化也仅在单因素分析中与RP相关(GPA比值比=0.21[95%CI:0.05;0.78];P=0.045)。
结论：声门下受累和弥漫性气道受累是胸部CT上GPA和RP区分的两个最相关的标准。尽管通常被认为是RP的高度暗示性标志，气管后膜保留是一种非特异性且过于主观的体征。
