PO115 - Delphi CT Phenotypes of Sarcoidosis: Reliability, and Lung Function Associations
Lisa A Maier, MD, MSPH (United States)1 2 3 4; Wren L Lippitt, PhD (United States)5; Giovanni Mancò, MD (Italy)6; Samuel Friedlander, MD (United States)7; Shu-Yi Liao, MD, MPD, ScD (United States)1 2 3 4; Briana Q Barkes, MPH (United States)1; Margaret M Mroz, MS (United States)1; Tasha E Fingerlin, PhD (United States)8; Nichole E Carlson, PhD (United States)9; David A Lynch, MB, BCh (United States)10;
1 - Department of Medicine, National Jewish Health, Denver, CO; 2 - Division of Environmental and Occupational Health Sciences National Jewish Health, Denver, CO; 3 - Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO; 4 - Department of Environmental and Occupational Health, University of Colorado Anschutz Medical Campus, Aurora, CO; 5 - Department of Biostatistics and Informatics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA; 6 - Department of Radiology, Ospedale Tappeiner; 7 - Department of Radiology, Duke University Medical Center; 8 - Department of Immunology and Genomic Medicine, National Jewish Health, Denver, CO; 9 - Department of Biostatistics and Informatics, University of Colorado Anschutz Medical Campus, Aurora, CO; 10 - Department of Radiology and Division of Environmental and Occupational Health Sciences, National Jewish Health, Denver, CO;
Keywords: High Resolution CT; Fibrotic Sarcoidosis; Interobserver Reliability;
Select the theme: Challenges in Sarcoidosis Diagnosis and Staging
Type: Original Papers
Presentation: Poster Presentation

Introduction: High-resolution computed tomography (HRCT) offers greater sensitivity than chest radiography for evaluating pulmonary sarcoidosis, but standardized phenotypic classification remains limited. A recent Delphi consensus study identified seven abnormal HRCT phenotypes (3 fibrotic, 4 non-fibrotic), yet their utility in clinical cohorts is unclear.

Objectives: To apply the Delphi phenotypes to a clinical sarcoidosis cohort, assess interobserver reliability, characterize CTs not fitting any phenotype, describe pulmonary function (PFTs; FEV1, FVC, FEV1/FVC, DLCO) by phenotype, and examine associations between PFTs and fibrotic grouping (fibrotic / non-fibrotic / normal) as characterized by Delphi phenotypes compared with grouping according to Scadding staging and direct CT visual assessment (CT VAS).

Materials and Methods: N=270 patients with HRCT and PFTs obtained within six months and previous CT VAS were analyzed retrospectively. Two blinded radiologists classified HRCT as one of seven Delphi phenotypes, normal, or “none of the above.” Interobserver agreement was assessed. Associations between fibrotic grouping and PFTs were evaluated using regression models adjusted for demographics.

Results: Delphi phenotyping classified approximately one-third as fibrotic, one-third as non-fibrotic, and the remainder as normal or none of the above. Inter-observer agreement was 83% for fibrotic grouping (Cohen’s κ = 0.76) and 70% for specific phenotype. Delphi fibrotic groupings were moderately concordant with Scadding (κ = 0.43) and CT VAS (κ = 0.59) groupings. Delphi fibrotic grouping was significantly associated with impaired lung function according to each PFT measure (p < 0.005). Adjusting for other fibrotic groupings attenuated functional associations but Delphi grouping remained informative for FEV1 and FEV1/FVC.

Conclusions: Delphi HRCT phenotypes demonstrate substantial inter-observer reliability and clinically relevant associations with lung function. However, approximately 9-15% of patients did not fit any phenotype, often due to predominant ground glass or mosaic attenuation.