Radiological phenotypes in pulmonary sarcoidosis: a reliability study of newly defined high-resolution computer tomography phenotypes

Objectives: An accurate morphological classification of distinct pulmonary phenotypes in sarcoidosis is lacking. Recently, a multinational Delphi study was conducted to reach a consensus on recognizable high-resolution computer tomography (HRCT) phenotypes in pulmonary sarcoidosis as a basis for a more distinctive classification. The reliability of these phenotypes has not yet been evaluated. Methods: HRCT scans of adult sarcoidosis patients from the pulmonology department of a single sarcoidosis referral center were scored by three blinded independent readers. Seven phenotypes were distinguished as described in the Delphi study. They were divided into two subgroups: "non-fibrotic" and "likely-to-be fibrotic". Intra- and inter-reader reliability for scoring the predominant phenotype and the subgroup was assessed using weighted Kappa (K-w) statistics. Results: Forty-five patients (mean age, 47 years +/- 12, 28 men) were included. For the scoring of the predominant phenotype, inter-reader reliability between all readers was substantial with an overall Fleiss' kappa of 0.69 (CI 0.622-0.765, P < .001). We observed a substantial inter-reader reliability between readers A and B (K-w of 0.76), between readers B and C (K-w of 0.66) and between readers A and C (K-w of 0.66). For the scoring of the subgroups "non-fibrotic" vs. "likely-to-be fibrotic," overall Fleiss' Kappa was substantial (K = 0.78, CI 0.607-0.944, P < .001). We observed a K-w score of 0.76 between readers A and B; 0.81 between readers A and C; 0.76 between readers B and C. Intra-reader reliability was substantial between the scores of A in scoring the predominant phenotypes (K-w of 0.71) and it was almost perfect in scoring the subgroups (K-w of 0.95). Intra-reader reliability was substantial between the scores of B in scoring the predominant phenotype (K-w of 0.66) and subgroups (K-w of 0.72). Conclusions: The inter- and intra-reader reliability of the newly proposed HRCT phenotypes obtained from the Delphi study is very acceptable.