Carlyne D. Cool Heather A. Lowers Leonard H. T. Go Lauren M. Zell-Baran Emily A. Sarver Kirsten S. Almberg Kathy D. Pang Susan M. Majka Angela D. Franko Naseema I. Vorajee Robert A. Cohen Cecil S. Rose Jeremy T. Hua 2024 <div class="title -title"><strong>Context.—</strong></div><p>Current approaches for characterizing retained lung dust using pathologists' qualitative assessment or scanning electron microscopy with energy-dispersive spectroscopy (SEM/EDS) have limitations.</p><div class="title -title"><strong>Objective.—</strong></div><p>To explore polarized light microscopy coupled with image-processing software, termed quantitative microscopy–particulate matter (QM-PM), as a tool to characterize in situ dust in lung tissue of US coal miners with progressive massive fibrosis.</p><div class="title -title"><strong>Design.—</strong></div><p>We developed a standardized protocol using microscopy images to characterize the in situ burden of birefringent crystalline silica/silicate particles (mineral density) and carbonaceous particles (pigment fraction). Mineral density and pigment fraction were compared with pathologists' qualitative assessments and SEM/EDS analyses. Particle features were compared between historical (born before 1930) and contemporary coal miners, who likely had different exposures following changes in mining technology.</p><div class="title -title"><strong>Results.—</strong></div><p>Lung tissue samples from 85 coal miners (62 historical and 23 contemporary) and 10 healthy controls were analyzed using QM-PM. Mineral density and pigment fraction measurements with QM-PM were comparable to consensus pathologists' scoring and SEM/EDS analyses. Contemporary miners had greater mineral density than historical miners (186 456 versus 63 727/mm³;<span>&nbsp;</span><i>P</i><span>&nbsp;</span>= .02) and controls (4542/mm³), consistent with higher amounts of silica/silicate dust. Contemporary and historical miners had similar particle sizes (median area, 1.00 versus 1.14 μm²;<span>&nbsp;</span><i>P</i><span>&nbsp;</span>= .46) and birefringence under polarized light (median grayscale brightness: 80.9 versus 87.6;<span>&nbsp;</span><i>P</i><span>&nbsp;</span>= .29).</p><div class="title -title"><strong>Conclusions.—</strong></div><p>QM-PM reliably characterizes in situ silica/silicate and carbonaceous particles in a reproducible, automated, accessible, and time/cost/labor-efficient manner, and shows promise as a tool for understanding occupational lung pathology and targeting exposure controls.</p> application/pdf 10.5858/arpa.2022-0427-OA en Allen Press Characterizing lung particulates using quantitative microscopy in coal miners with severe pneumoconiosis article