Related Experiment Video
Updated: May 26, 2026
Imaging Features of Systemic Sclerosis-Associated Interstitial Lung Disease
Published on: June 16, 2020
Meaningful thresholds for change in quantitative computed tomography-derived fibrosis extent in idiopathic pulmonary
Dong Yeong Kim1, Min-Ju Kim2, Yu Jin Oh3
1Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea.
Rationale:
Validated thresholds for clinically meaningful change in quantitative computed tomography (QCT) for fibrosis extent across algorithms remain unclear in idiopathic pulmonary fibrosis (IPF).
Objectives:
To evaluate minimal clinically important difference (MCID) for 1-year change in QCT metrics in IPF using different algorithms than previously reported and to identify prognostically meaningful thresholds for effective risk stratification.
Methods:
This multicenter retrospective study included IPF patients with baseline and 1-year follow-up CT. Minimal clinically important differences for change in fibrosis score (ΔFS) derived from fully automated CT quantification were estimated using an anchor-based approach with 1-year changes in FVC and diffusing capacity for carbon monoxide (DLco), and a prognostic threshold was estimated using maximally selected log-rank statistics. Prognostic significance of ΔFS was evaluated in discovery and validation cohorts.
Results:
The discovery cohort included 524 patients (mean age = 66.8 years; 79% men), and the external validation cohort included 224 patients (mean age = 69.6 years; 83% men). Anchor-based MCIDs were 2.72% for FVC and 4.52% for DLco, with a prognostic threshold of 4.05%. In the discovery cohort, 1-year ΔFS were independently associated with transplant-free survival (TFS), with greater risk when ΔFS exceeded MCID or prognostic thresholds (all, P < .001). In the validation cohort, ΔFS remained associated with TFS (adjusted hazard ratio [aHR] = 1.11; 95% CI, 1.04-1.18), and all prespecified ΔFS thresholds were prognostic for overall TFS, with the prognostic threshold of ΔFS ≥ 4.05% showing the most consistent associations with overall (aHR = 2.78; 95% CI, 1.36-5.68) and 3-year TFS (aHR = 2.88; 95% CI, 1.11-7.48).
Conclusion:
One-year change in FS and its thresholds were significantly associated with TFS, supporting annual CT follow-up with predefined QCT thresholds for monitoring and risk stratification in IPF.
