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Updated: Jun 25, 2026
04:44
Imaging Features of Systemic Sclerosis-Associated Interstitial Lung Disease
Published on: June 16, 2020
Small airways obstruction syndrome in clinical practice
Chiung-Zuei Chen1, Chien-Chung Lin, Cheng-Hung Lee
1Division of Chest Medicine, Department of Internal Medicine, National Cheng Kung University Medical College and Hospital, Tainan, Taiwan.
Respirology (Carlton, Vic.)
|February 12, 2009
Summary
Small airways obstruction syndrome (SAOS), a pulmonary function test pattern, is not uncommon. Early interstitial lung disease, chest wall deformity, and asthma are its most frequent causes, aiding clinical diagnosis.
Area of Science:
- Pulmonary Medicine
- Diagnostic Imaging
- Clinical Pathology
Background:
- Small airways obstruction syndrome (SAOS) is defined by specific pulmonary function test (PFT) results: decreased vital capacity (VC) and forced expiratory volume in 1 second (FEV1) with normal FEV1/VC ratio and total lung capacity (TLC).
- The clinical significance and diagnostic implications of SAOS have remained under-investigated.
Purpose of the Study:
- To investigate the prevalence and causes of SAOS.
- To develop and validate a diagnostic algorithm for SAOS.
Main Methods:
- Retrospective analysis of PFT results from a university teaching hospital over one year.
- Development and validation of a simplified algorithm for differential diagnosis of SAOS.
Main Results:
- SAOS pattern was identified in 4.8% of 3207 PFTs.
- Confirmed diagnoses for 85 patients revealed early interstitial lung disease (23.3%), chest wall deformity (14.1%), and asthma (11.6%) as leading causes.
- A validated algorithm achieved 91% accuracy in identifying restrictive and obstructive ventilatory defects contributing to SAOS.
Conclusions:
- SAOS is a relatively common PFT finding.
- Early interstitial lung disease, chest wall deformity, and asthma are primary contributors to SAOS.
- A proposed diagnostic algorithm can assist clinicians in diagnosing SAOS.
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