Clinical Characteristics and Prevalence of Apical Scarring at Chest CT in a Healthy Population

Purpose To determine the prevalence of apical scarring-which has recently also been referred to as pleuroparenchymal fibroelastosis (PPFE)-like lesions, a characteristic finding at chest CT in idiopathic PPFE-in apparently healthy individuals, to identify associated clinical features, and to evaluate their progression over time. Materials and Methods This retrospective study included individuals without underlying diseases known to cause PPFE, who underwent comprehensive health checkups including chest CT between April 2014 and March 2015 (cohort 1: <i>n</i> = 1737; cohort 2: <i>n</i> = 1126). Clinical features associated with the presence of apical scarring were analyzed using propensity score matching and logistic regression analysis. Furthermore, in a subset of individuals with available follow-up data, radiologic progression of apical scarring was evaluated over a 4-year period from baseline, and potential risk factors were evaluated using a logistic regression model. Results Among 2863 individuals (median age, 57 years [IQR, 49-65 years]; 2299 male), 158 (5.5%) had apical scarring, with prevalence rates of 1.6%, 3.9%, and 8.1% in individuals aged 20-39 years, 40-59 years, and 60 years and older, respectively. Older age and lower body mass index, body fat, and waist circumference were associated with apical scarring. These findings were consistent in both cohorts. Among the 158 individuals with apical scarring, at least 20 (12.7%) demonstrated radiologic progression over 4 years, which was more common in those with more extensive lesions at baseline (progression rate: grade 1 lesions, 19.2% vs grade 2 lesions, 66.7%; <i>P</i> = .006). Conclusion Among apparently healthy individuals, the prevalence of apical scarring increased with age, and its presence was associated with a lean body habitus. Radiologic progression was observed in some individuals. <b>Keywords:</b> CT, Thorax, Lung, Epidemiology, Apical Cap, Interstitial Lung Disease, PPFE, PPFE-like lesions, Pleuroparenchymal Fibroelastosis <i>Supplemental material is available for this article.</i> © RSNA, 2026.