Chest CT scans obtained at the time of the diagnosis of pneumonitis were reviewed by a consensus of three radiologists with expertise in thoracic and oncologic imaging (M.N., N.H.R., H.H.), as described previously.(24 (link)–27 (link)) CT findings of pneumonitis were evaluated for 1) extent in upper, middle and lower lungs (none, <5%, 5–25%,25–50%, >50%), 2) distributions in terms of (a) peripheral, diffuse, central or mixed; and (b) upper, lower, diffuse, multifocal or focal, 3) lobar involvement, and 4) specific CT findings including traction bronchiectasis, consolidation, reticular opacities, ground glass opacities (GGO), centrilobular nodularity, and honeycombing.(24 (link)–27 (link)) In each case, radiographic patterns of pneumonitis were classified referring to ATS/ERS international multidisciplinary classification of interstitial pneumonias, as 1) usual interstitial pneumonia (UIP) pattern, 2) non-specific interstitial pneumonia (NSIP) pattern, 3) cryptogenic organizing pneumonia (COP) pattern, 4) acute interstitial pneumonia (AIP)/acute respiratory distress syndrome (ARDS) pattern, 5) hypersensitivity pneumonitis (HP) pattern, and 6) not applicable, as described previously.(24 (link)–28 (link)) Follow-up chest imaging studies after the onset of pneumonitis were also reviewed to assess the resolution of the findings.