AbstractBackground and ObjectiveThere is increasing interest in the role of lipids in processes that modulate lung fibrosis with evidence of lipid deposition in idiopathic pulmonary fibrosis (IPF) histological specimens. The aim of this study was to identify measurable markers of pulmonary lipid that may have utility as IPF biomarkers.Study Design and MethodsIPF and control lung biopsy specimens were analysed using a unbiased lipidomic approach. Pulmonary fat attenuation volume (PFAV) was assessed on chest CT images (CT_PFAV) with 3D semi‐automated lung density software. Aerated lung was semi‐automatically segmented and CT_PFAV calculated using a Hounsfield‐unit (−40 to −200HU) threshold range expressed as a percentage of total lung volume. CT_PFAV was compared to pulmonary function, serum lipids and qualitative CT fibrosis scores.ResultsThere was a significant increase in total lipid content on histological analysis of IPF lung tissue (23.16 nmol/mg) compared to controls (18.66 mol/mg, p = 0.0317). The median CT_PFAV in IPF was higher than controls (1.34% vs. 0.72%, p < 0.001) and CT_PFAV correlated significantly with DLCO% predicted (R² = 0.356, p < 0.0001) and FVC% predicted (R² = 0.407, p < 0.0001) in patients with IPF. CT_PFAV correlated with CT features of fibrosis; higher CT_PFAV was associated with >10% reticulation (1.6% vs. 0.94%, p = 0.0017) and >10% honeycombing (1.87% vs. 1.12%, p = 0.0003). CT_PFAV showed no correlation with serum lipids.ConclusionCT_PFAV is an easily quantifiable non‐invasive measure of pulmonary lipids. In this pilot study, CT_PFAV correlates with pulmonary function and radiological features of IPF and could function as a potential biomarker for IPF disease severity assessment.