More than half of World Trade Center responders with available CT scans had evidence of pulmonary nodules, a recent study shows.

Researchers examined CT imaging data from 1,617 World Trade Center responders taken between 2003 and 2012 from the WTC Chest CT Imaging Archive and the WTC General Responder Cohort Data Center. The study’s primary outcome was the presence of noncalcified nodules, with radiologists evaluating nodule location, consistency, size at largest diameter and presence of calcification. Severity of nodules were classified according to the Lung CT Screening Reporting and Data System (Lung-RADS) criteria.

Arrival at the World Trade Center within 48 hours of the 9/11 attack and World Trade Center exposure duration with a cutoff of 60 days were used as measures for World Trade Center exposure. Multivariable analysis included adjustment for sex, race, age at time of CT scan, educational attainment, income, smoking intensity and status at baseline screening and pre-9/11 occupational exposures, with pleural thickening used as a measure of pre-9/11 respiratory asbestos exposure.

Of the 1,617 participants, 60% had at least one pulmonary nodule, with 52% showing at least one noncalcified solid nodule. Additionally, 55% of all participants had a nodule severity of Lung-RADS 2 and 5% had a nodule severity of Lung-RADS 3 or 4.