Document resource
Introduction Idiopathic pulmonary fibrosis (IPF) and fibrotic hypersensitivity pneumonitis (fHP) cause significant morbidity and mortality. Quantitative computed tomography (qCT) may provide radiomic biomarkers to assist in the prognostication and disease monitoring of these conditions. We aimed to investigate a prognostic role for qCT in fHP and IPF.Methods This retrospective, observational, multicentre study analysed electronic records of patients with an ILD multidisciplinary diagnosis of fHP or IPF. Patients required ≥1 HRCT and ≥2 pulmonary function tests (PFTs) between 2015 and 2022. Data were censored on 30/01/2025. Demographics, PFTs, bronchoalveolar lavage (BAL), CT scans, and survival data were recorded. Brainomix e-Lung used deep-learning to derive radiomic biomarkers from anonymised scans.Correlations between PFTs and qCT was assessed using Pearsons correlation. For patients with baseline paired PFTs and qCT and ≥12 months follow-up Cox proportional hazards models were used to assess association of qCT, age, sex, smoking status, Charlson comorbidity index and baseline PFTs with progression-free survival (time to 10% FVC decline, 15% TLCO decline, or death).Results 155 patients with fHP and 216 with IPF were included. Of the CT scans, 485/558 (fHP) and 388/456 (IPF) had successful quantitative analysis, and 304/558 (fHP) and 338/456 (IPF) had paired PFTs (within 90 days of scan acquisition). Forced vital capacity (FVC)% predicted and transfer factor (TLCO)% predicted correlated with e-Lung’s radiomic weighted reticulovascular score (WRVS) in both fHP (r=-0.56 and r=-0.49 respectively, both p<0.05) and IPF (r=-0.52 and r=-0.57 respectively, both p<0.05) across all paired scans.In patients with fHP, BAL lymphocytosis was negatively correlated with WRVS (n=45, r=-0.352, p=0.02).Table 1 summarises patients included in the Cox proportional hazards analysis, WRVS was independently associated with progression-free survival in both IPF and fHP (fHP: HR 1.08, 95%CI 1.03–1.12, p<0.05; IPF: HR 1.08, 95%CI 1.02–1.15, p<0.05).Abstract S13 Table 1Patients included in Cox proportional hazards model of progression free survival in idiopathic pulmonary fibrosis and fibrotic hypersensitivity pneumonitis Fibrotic hypersensitivity pneumonitis Idiopathic pulmonary fibrosis Patient (n) 107 113 Follow-up median (months) (IQR) 22.5 (12.8–38.6) 21.1 (11.9–32.6) Sex - Male 45 (42%) 100 (88.4%) Mean age at baseline (±SD) 71.0 (8.8) 73.4 (9.7) Ever smoker 60 (56.1%) 84 (74.3%) Charlson comorbidity index median (IQR) 4 (3–5) 4 (4–5) Mean FVC% predicted at baseline (±SD) 77.5% (16.7%) 82.8% (16.1%) Mean TLCO% predicted at baseline (±SD) 61.2% (17.4%) 57.5% (15.1%) Legend: IQR=interquartile range; SD=standard deviationConclusions WRVS correlates with PFTs and is negatively associated with lymphocytosis on BAL, highlighting the potential for WRVS to assess non-fibrotic burden in fHP patients. Baseline WRVS is associated with progression-free survival in both IPF and fHP and may aid prognostication in these patient groups.