Objective To analyze the CT features of immune checkpoint inhibitor-related pneumonia (CIP) and improve the diagnostic accuracy of CIP. Methods Among patients with malignant tumor treated with immune checkpoint inhibitors, those who developed pneumonia and rule out other causes of disease were identified. Chest CT Imaging were reviewed to assess special signs, distribution characteristics, severity of pneumonia and radiographic patterns of CIP. Results A total of 28 patients were enrolled, including 26 males and 2 females. CT features include ground-glass opacity, centrilobular nodularity, reticular opacity, consolidation, traction bronchiectasis, honeycomb, etc. The lesions predominant involved peripheral lung zone (17/28), lower lung zone (18/28) and posterior lung zone (18/28), with a diffuse distribution (23/28). In most cases the disease involved both lungs (23/28), and a few involved unilateral or single lobe. The most common affected lobes were the lower lobe of the right lung (25/28) and the lower lobe of the left lung (20/28), followed by the upper lobe of the right lung (18/28). Mean pneumonia severity score was 5.5, standard deviation was 3.8, and range was 1 - 15. The most common radiographic patterns of CIP were nonspecific interstitial pneumonia (11/28) and hypersensitivity pneumonia (10/28). The second was organizing pneumonia (6/28). Conclusions The CT manifestations of CIP have certain specificity. Combined with the history of drug treatment and clinical symptoms of patients, the early and correct diagnosis can be obtained.

Citation： CHAI Xiaoming, YANG Xiurong. CT features of immune checkpoint inhibitor-related pneumonia. Chinese Journal of Respiratory and Critical Care Medicine, 2023, 22(4): 232-236. doi: 10.7507/1671-6205.202209024 Copy