Autoimmune-Associated Interstitial Lung Disease: Imaging Phenotypes

Recognizing characteristic traits, or phenotypes, of Autoimmune-Associated Interstitial Lung Disease (AA-ILD) on HRCT imaging assists in diagnosis, prognosis, treatment decisions and imaging surveillance. The primary AA-ILD imaging phenotypes considered include pulmonary parenchymal patterns, extrapulmonary associated findings, clinical context and change over time. Focusing on the imaging appearance of the major interstitial pneumonia patterns by histopathologic categories, the localized imaging features defined by the secondary pulmonary lobule, and the growing list of sub-patterns or imaging signs, we begin to bridge the gap between the strictly defined categories studied in the literature with the often vague "feel" of AA-ILD imaging in clinical practice. Furthermore, this review explores the current and future applications of automated CT assessment in AA-ILD imaging phenotypes.