Background: There is growing interest in identifying early stages of interstitial lung disease (ILD) to improve patient outcomes. This document reviews updated evidence on interstitial lung abnormalities (ILA), provides suggestions for screening, evaluation, and management, proposes criteria for distinguishing ILA from ILD, and identifies research priorities. 

Methods: A committee of clinical and methodology experts met by video conference to define ILA and ILD by consensus and voted on eleven pre-specified questions after reviewing synthesized evidence from a systematic literature search. Agreement of 70% or more was required to approve each suggestion. 

Results: ILA is defined as non-dependent bilateral parenchymal CT abnormalities, including ground-glass or reticulations, lung distortion, traction bronchiectasis, and/or honeycombing involving at least 5% of a lung zone. The updated definition removes prior exclusion of high-risk populations. ILD is distinguished from ILA by symptoms (dyspnea/cough) attributable to an interstitial process, abnormal or declining lung function, fibrotic (honeycombing and/or reticulation with traction bronchiectasis involving at least 5% of total lung volume) or progressive imaging abnormalities, and/or specific fibrotic ILD patterns on imaging or pathology. 

Suggestions include ILA/ILD assessment on imaging acquired for lung cancer screening, screening adults with connective tissue disease and first-degree relatives of patients with familial pulmonary fibrosis, assessing baseline symptoms and pulmonary function among those with ILA, and monitoring ILA with chest CT every 2-3 years. 

Conclusion: This document presents a comprehensive literature review of ILA with updates to the Fleischner Society ILA definition, establishes a working ILD definition, and provides evidence-based suggestions for ILA evaluation and management.

背景：识别间质性肺病（ILD）早期阶段以改善患者预后的研究兴趣日益增加。本文综述了间质性肺异常（ILA）的最新证据，提供筛查、评估和管理建议，提出区分ILA与ILD的标准，并明确研究重点。

方法：临床与方法学专家委员会通过视频会议达成共识，对ILA和ILD进行定义，并在回顾系统文献检索的综合证据后，对11个预设问题进行投票。每项建议需获得至少70%的同意率方可通过。

结果：ILA定义为非重力依赖的双侧肺实质CT异常，包括磨玻璃影或网状影、肺结构扭曲、牵拉性支气管扩张和/或蜂窝肺，累及至少5%的肺区。更新后的定义删除了既往对高危人群的排除标准。ILD与ILA的区别在于：存在可归因于间质性病变的症状（呼吸困难/咳嗽）、肺功能异常或进行性下降、纤维化影像学表现（蜂窝肺和/或网状影伴牵拉性支气管扩张，累及至少5%肺容积）或进行性影像学异常，及/或影像学或病理学上的特定纤维化ILD模式。

建议：在肺癌筛查影像中评估ILA/ILD；对结缔组织病患者及家族性肺纤维化患者的一级亲属进行筛查；对ILA患者评估基线症状和肺功能；每2-3年行胸部CT监测ILA。

结论：本文对ILA进行了全面文献综述，更新了Fleischner学会的ILA定义，建立了ILD工作定义，并为ILA评估与管理提供了基于证据的建议。