Correlation between HRTC appearance and histopathological features in the diagnosis of interstitial lung diseases

Background: According to current guidelines, when a high-confidence radiologic diagnosis of usual interstitial pneumonia (UIP) is made on thin-section computed tomography (HRCT), surgical biopsy is rarely required. Nevertheless, the disowning of HRCT-scans diagnoses by biopsy is not a rare event as presumed. Aim of our study is to describe the rate of concordance between HRCT-scans and pathological diagnoses. Methods: Patients who underwent mini-invasive surgical biopsy for interstitial lung diseases, from 2013 to 2017 were analyzed. The HRCT-scans were reviewed by an observer blinded to clinical information of patients. The concordance between histological and HRCT-scan were assessed. Results: Data of 35 patients with uncertain HRCT diagnosis of interstitial lung diseases were analyzed. Most of the patients are male (21-60%). The more frequent HRCT pattern was the UIP inconsistent (17–49%), followed by the UIP possible (12–34%), the consolidation (3–9%), the ground glass opacity (1-3%), the non-specific interstitial pneumonia (NSIP) (1–3%) and others (1-3%). The more common histological diagnosis was the cronic hypersensivity pneumonitis (8–23%), followed by the UIP-like pattern (7–20%), the Sarcoidosis (5-14%), the others (7-20%). In 7 (20%) cases final pathological finding denies HRCT-scans diagnoses; indeed, a moderate agreement between HRCT-scan findings and the final histological diagnosis was observed (kappa index:0.42). Conclusions: HRCT-scan have limitations if the objective is to accurate define interstitial lung diseases. Consequently, pathological assessing should be taken into account, in order to provide more accurate tailored treatment strategies.