RT Journal Article SR Electronic T1 Assessment of alveolar-capillary membrane permeability using Tc99m – DTPA aerosols in diffuse systemic sclerosis – a cross sectional study JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP PA2340 DO 10.1183/13993003.congress-2021.PA2340 VO 58 IS suppl 65 A1 Muniza Bai A1 Dharm Prakash Dwivedi A1 G Vishnukanth A1 Nandini Pandit A1 K G Chengappa A1 A Subathra A1 R Sivaranjini YR 2021 UL http://erj.ersjournals.com/content/58/suppl_65/PA2340.abstract AB Objectives: 1. To assess the alveolar capillary permeability in patients with diffuse systemic sclerosis (dcSSc) using Tc 99m DTPA aerosol scintigraphy.2. To identify the association of DTPA clearance rates with spirometry, HRCT, six minute walk distance (6MWD), modified rodnan skin score (mRSS), nail fold capillaroscopy (NFC), serum KL-6, SP-D and Saint George’s Respiratory Questionnaire (SGRQ).Methodology: A cross-sectional study was made between December 2018 and December 2020 at a tertiary care hospital in South India after institutional ethics committee clearance. Cases of dcSSc satisfying the ACR/EULAR 2013 criteria were recruited into the study after obtaining consent. They underwent aerosol scintigraphy, HRCT thorax, spirometry, mRSS, NFC, 6MWT, SGRQ and serum testing for KL-6, SP-D.Results: Of the total participants (n=58), the mean DTPA clearance rate (T1/2) was found to be 49.6±25.7 minutes. ROC analysis determined 59.5 minutes as the cut off for detecting the presence of ILD (sensitivity 81.2%, specificity 66.7% when compared to HRCT). Clearance T1/2 correlated positively with Warrick CT score, 6MWD, post 6MWD BORGD and negatively with FVC, mRSS.Conclusion: Aerosol scintigraphy can serve as a novel diagnostic modality for the early diagnosis of ILD in dcSSc and its results correlated with the existing clinical measures. Utility of aerosol scan needs to be studied in other forms of ILD.FootnotesCite this article as: European Respiratory Journal 2021; 58: Suppl. 65, PA2340.This abstract was presented at the 2021 ERS International Congress, in session “Prediction of exacerbations in patients with COPD”.This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).