Feasibility, face, and content validity of quantitative computed tomography in interstitial lung disease related to connective tissue diseases

Objectives: Quantitative computed tomography (QCT) is a promising tool for objective assessment of interstitial lung disease (ILD) related to connective tissue diseases (CTD). However, its validity was never investigated. The aim of this study was to assess QCT feasibility, face, and content validity evaluation concerning CTD-ILD. Methods: A rheumatologist and a chest radiologist conceived an online survey with nine statements: Two about general issue involving CTD-ILD, one for the face validity, three both for content validity and feasibility. Each statement had to be rated with a score from 0 to 100, respectively, (complete disagreement and agreement). We considered a statement supported by the experts if the median score was ≥75.0. Results: A panel of 14 experts (11 from Europe, three from America) with a nine years median experience was enrolled. All the statements about feasibility, face and content validity were supported, except for QCT capability to recognize elementary lesions. Conclusions: The panel of experts supported feasibility, face, and content validity of QCT assessment concerning CTD-ILD. This may stimulate a greater use in clinical practice and further studies to confirm its discriminative properties and its construct validity.