The incidence of interstitial lung abnormalities on computed tomography pulmonary artery protocol: a retrospective study

SESSION TITLE: Diffuse Lung Disease Posters 3 SESSION TYPE: Original Investigation Posters PRESENTED ON: 10/10/2023 12:00 pm - 12:45 pm PURPOSE: Interstitial lung abnormalities (ILAs) are an increasingly recognized finding on lung computed tomography (CT) scans, with a prevalence ranging from 3-17%. These findings have been identified in elderly or smoking populations via non-contrasted CT scans. Individuals with ILAs have increased morbidity and a subset of individuals will have progression of disease to interstitial lung disease (ILD). To our knowledge no data exists in contrasted CT scan cohorts. Scant data exists in which the Fleischner criteria has been used to identify ILAs. The purpose of this study is to identify the incidence of ILAs on CTPAs in a cohort of patients across two urban Emergency Departments. METHODS: This is a single-center retrospective review of computed tomography wit pulmonary angiography (CTPA) scans obtained between May 2009 and July 2010. Reviewer (RG) identified scans with presumed ILAs, which were then reviewed by an ILD Pulmonologist (PC). If there were discrepancies, then the scan in question was reviewed by a chest radiologist (ZK). RESULTS: We reviewed 990 charts and identified patients who had follow-up chest CT scans with or without contrast at least 1 year after the original. We identified 383 charts with follow-up imaging. 31/383 (8.1%) had an ILA on the initial scan. The mean age of those with ILAs was 68.1 years and mean time to follow-up imaging was 6.8 years. Follow-up imaging revealed progression to ILD in 4/31 (12.9%), resolution of ILA in 3/31 (9.7%) and stable scan in 24/31 (77.4%). Of the 4 with progression, one was diagnosed with sarcoid, one with eGPA, one with probable chronic HP, and one that was lost to follow-up. Mean time to follow-up imaging in these 4 patients was 11.6 years. More than half of patients with ILAs did not have Pulmonary Function Tests (PFTs) nor pulmonology follow-up (16/31, 51.6%) despite abnormal imaging. CONCLUSIONS: In this retrospective study, we demonstrate a similar incidence of ILAs as that of published literature (8.1%). To our knowledge, this is the first study in which contrasted scans were used to identify ILAs. The ability to detect early interstitial changes on contrasted scans could allow for early recognition of at-risk individuals. 51.6% of patients with ILAs were not referred to a pulmonologist, nor were PFTS obtained. This suggests that at the time of image acquisition, many practitioners may have been unaware of ILAs and their significance. CLINICAL IMPLICATIONS: This is, to our knowledge, the first study to identify ILAs via contrasted imaging. The incidence of ILAs in our cohort aligns with previously published data. The use of CTPAs, in combination with increasing awareness of ILAs and advancements in imaging analytics, may allow for the early diagnosis and monitoring of radiographic abnormalities that have the possibility of progressing to ILD. DISCLOSURES: Consultant relationship with BD Please note: $5001 - $20000 by Joseph Bledsoe, value=Consulting fee Advisory Committee Member relationship with Baxter Health Please note: 11/4-11/21 2022 Added 03/29/2023 by Joseph Bledsoe, source=Web Response, value=Honoraria No disclosure on file for Peter Crossno I received research funds from the entit relationship with Janssen Pharmaceuticals Please note: 10/1/2019-9/30/2022 Added 03/29/2023 by Mark Dodson, source=Web Response, value=Grant/Research No relevant relationships by C Elliott No relevant relationships by Ryan Gil No relevant relationships by Daniel Knox No disclosure on file for Zachary Krahn No relevant relationships by Brittany Scarpato