The Use of Computed Tomography Densitometry for the Assessment of Emphysema in Clinical Trials: A Position Paper from the Fleischner Society.
Summary
This Fleischner Society position paper synthesizes evidence that CT densitometry (e.g., %LAA<-950 HU) and volume-adjusted lung density are validated, reproducible biomarkers for emphysema diagnosis, prognosis, and monitoring in trials. It issues practical standards for acquisition, analysis, and longitudinal assessment, with scan–rescan ICC of 0.99 when techniques are standardized.
Key Findings
- CT densitometry metrics (e.g., %LAA<-950 HU) are validated diagnostic and prognostic biomarkers for emphysema.
- Volume-adjusted lung density is recommended for longitudinal disease monitoring in trials.
- With standardized techniques, scan–rescan intraclass correlation coefficients reach 0.99, supporting high reproducibility.
Clinical Implications
Adopt standardized CT protocols and volume-adjusted lung density for longitudinal monitoring in emphysema trials; consider %LAA<-950 HU for diagnostic/prognostic stratification.
Why It Matters
It provides consensus standards that enable consistent use of CT metrics as trial endpoints, potentially accelerating drug development and harmonizing multicenter COPD studies.
Limitations
- Position paper consensus without prospective RCT validation of surrogate endpoints
- Heterogeneity in legacy CT protocols and software across centers may persist
Future Directions
Prospective validation of CT densitometry as a surrogate endpoint for hard outcomes; harmonization across scanners/vendors; regulatory qualification of imaging biomarkers.
Study Information
- Study Type
- Systematic Review
- Research Domain
- Diagnosis
- Evidence Level
- III - Expert consensus and systematic review without randomized trial testing of endpoints
- Study Design
- OTHER