Bronchoalveolar lavage (BAL) cellular analysis is often recommended during the initial diagnostic evaluation of fibrotic interstitial lung disease (ILD). Despite recommendation for its use, between-center heterogeneity exists and supportive data concerning the clinical utility and correlation of BAL findings with radiologic features or patterns remain sparse. In patients with fibrotic ILD, are BAL findings associated with radiologic features, patterns, and clinical diagnoses? Patients with fibrotic ILD who underwent BAL for diagnostic evaluation and who were enrolled in the prospective Canadian Registry for Pulmonary Fibrosis were re-reviewed in a standardized multidisciplinary discussion (MDD). BAL was categorized according to guideline-recommended thresholds, and using thresholds of lymphocytosis > 20% and neutrophils > 4.5%. High-resolution CT (HRCT) scans were scored (blinded to clinical data) for specific features and percentage lung involvement. Radiologists classified HRCT scans according to guideline-defined patterns for idiopathic pulmonary fibrosis and fibrotic hypersensitivity pneumonitis (fHP); then, MDD diagnoses were assigned, considering all available data. Bronchoscopy with cellular analysis was performed in 209 of 1,593 patients (13%). Lymphocyte % was weakly negatively correlated with total fibrosis % ( = –0.16, = .023) but not statistically significantly correlated with ground glass opacity % ( = 0.01, = .94). A mixed BAL pattern was the most frequent in all radiologic patterns (range, 45%-69%), with a minority classifiable according to BAL guidelines. BAL lymphocytosis appeared with similar frequency across HRCT patterns of fHP (21%) and usual interstitial pneumonia (18%). Only 5% of patients with MDD-based fHP had a guideline-defined isolated lymphocytosis > 15%. BAL cellular analyses did not significantly correlate with radiologic features, guideline patterns, or MDD-based diagnoses. Ground glass opacities are often interpreted to represent pulmonary inflammation, but were not associated with BAL lymphocytosis in this cohort.

中文翻译：

---

纤维化间质性肺病患者的支气管肺泡灌洗液细胞分析和放射学模式


在纤维化间质性肺疾病 (ILD) 的初始诊断评估过程中，通常建议进行支气管肺泡灌洗 (BAL) 细胞分析。尽管建议使用它，但中心间的异质性仍然存在，并且有关临床效用以及 BAL 结果与放射学特征或模式的相关性的支持数据仍然很少。在纤维化 ILD 患者中，BAL 结果与放射学特征、模式和临床诊断相关吗？接受 BAL 进行诊断评估并参加加拿大肺纤维化前瞻性登记的纤维化 ILD 患者在标准化多学科讨论 (MDD) 中接受重新审查。 BAL 根据指南推荐的阈值进行分类，并使用淋巴细胞增多阈值 > 20% 和中性粒细胞阈值 > 4.5%。对高分辨率 CT (HRCT) 扫描进行评分（对临床数据不知情），以了解具体特征和肺部受累百分比。放射科医生根据指南定义的特发性肺纤维化和纤维化过敏性肺炎 (fHP) 模式对 HRCT 扫描进行分类；然后，考虑所有可用数据，分配 MDD 诊断。对 1,593 名患者中的 209 名 (13%) 进行了支气管镜检查和细胞分析。淋巴细胞百分比与总纤维化百分比呈弱负相关 (= –0.16, = .023)，但与毛玻璃混浊百分比 (= 0.01, = .94) 之间无统计学显着相关性。混合 BAL 模式是所有放射学模式中最常见的（范围为 45%-69%），少数可根据 BAL 指南进行分类。在 fHP (21%) 和普通间质性肺炎 (18%) 的 HRCT 模式中，BAL 淋巴细胞增多的出现频率相似。 只有 5% 的基于 MDD 的 fHP 患者出现指南定义的孤立性淋巴细胞增多症 > 15%。 BAL 细胞分析与放射学特征、指导模式或基于 MDD 的诊断没有显着相关性。磨玻璃样混浊通常被解释为代表肺部炎症，但在该队列中与 BAL 淋巴细胞增多无关。