Pleuroparenchymal fibroelastosis (PPFE)-like finding on CT in daily practice ―prevalence and serial changes

OBJECTIVE: To characterize the prevalence of PPFE (pleuroparenchymal fibroelastosis)-like finding on CT in daily practice and to identify the risk factors for its progression. MATELIALS & METHODS: 2416 consecutive daily CT examinations were screened for PPFE-like finding. CT images with PPFE-like finding were retrospectively reviewed for the extent, maximum height, presence or absence of intraalveolar fibroelastosis (IAFE), emphysema, interstitial lung disease (ILD), suprasternal depression at the level of clavicle end, and bronchiectasis in upper lobe, and anterior-posterior/transverse diameter ratio (AT ratio) of thoracic cage. Serial CT scans more than 3 years before the baseline scan were also reviewed and compared when available. RESULTS: 380 patients (median age of 65, M:F = 153:227) were recognized as having PPFE-like finding. The lowest level of PPFE-like finding was T5 in median, horizontal extent was 0–25 % in 229/380, 25–50 % in 66 and >50 % in 24. Median height was 8.0 mm. IAFE was seen in 75, emphysema in 71, ILD in 59, chronic bronchial disorder in 71, suprasternal depression in 148, upper-lobe bronchial dilatation in 124. Mean AT ratio was 0.63. Serial images were available in 131 patients. 11 showed significant progression, 57 showed mild progression. Existing ILD lesion and >25 % horizontal extent were significantly related to significant progression. CONCLUSIONS: PPFE-like finding was seen relatively in high proportion. Extensive lesion in axial plane and co-existing ILD might be risk factors of progression.