B78-10 Computed Tomography Ventilation and Perfusion Mapping of Lobar Patterns in Biomass and Tobacco-Related Chronic Obstructive Pulmonary Disease

Introduction Exposure to varying sources of air pollution results in distinct ventilation-perfusion (V/Q) gradients, and mismatching. Lengthened exposure to biomass correlates to bronchial wall-thickening and air-trapping, where cumulative tobacco-smoke exposure is closely associated with emphysema. Resource-limited settings rely heavily on biomass for heating, cooking, and lighting in dwellings with poor ventilation. Despite the global prevalence of biomass-related air-pollution, few studies have examined effects on lung function through novel analytic technologies, particularly in low/middle-income countries. The current study aims to characterize physiological markers of differing environmental exposures, employing a novel CT-based technique to generate sensitive, quantitative V/Q metrics in a Ugandan population. Methods Participants were recruited with informed consent from Nakaseke, Uganda. Environmental exposure was determined through self-reported questionnaires and personal exposure-monitoring. Tobacco exposure was categorized as either current or former smoking. Non-contrast inspiratory & expiratory CT scans were completed and deformable image registration was applied to develop voxel-based V/Q maps. Tissue density & regional V/Q distributions were subsequently quantified for each participant across five anatomically defined regions (Figure 1), for assessment of spatial heterogeneity in V/Q matching. To compare differences within regions, Hodges-Lehmann (HL) median difference (Tobacco − Biomass) with a 95% CI was used. Results Of the total 38 participants, 15 were exposed to tobacco, while the remaining 23 were exposed to biomass only. In the tobacco-group, the proportion of ventilated tissue was lower than the biomass group in apical regions of the lung (HL diff RUL, LUL =-0.056, -0.080). The tobacco group ventilation additionally was higher in comparison to the biomass group in basal regions (HL diff RLL, LLL = +0.045, +0.043). Among tobacco-exposed participants, there was greater perfusion distribution in the apical regions in comparison to participants exposed to biomass smoke, in the RUL (HL diff = +0.031). Discussion The current study is the first to utilize CT-V/Q technology outside of clinical validation efforts. Results highlight the capacity of CT-V/Q to uncover distinct quantitative apical/basal V/Q gradient patterns in individuals exposed to tobacco smoke or biomass, analyzing subtle region-specific functional differences beyond conventional anatomic insights. Collectively, the current study raises a need for further investigation regarding phenotypic and functional consequences of chronic biomass exposure, utilizing larger sample sizes within developing regions of the world.