To educate the general radiologist about imaging findings they may encounter related to common and important immune related adverse events (irAEs) as a result of treatment with immune checkpoint inhibitors (ICIs).

Recently the treatment of a variety of advanced cancers has been revolutionised with the use of immunotherapy, in particular ICIs [1-5]. Due to the growing use of ICIs and the integral role of imaging in cancer care, radiologists must be aware of their treatment response patterns and adverse side effects, which may differ from conventional chemotherapies and can be complex [1,3,6]. This is particularly pertinent given the increased use of telehealth related to the covid-19 pandemic, which has seen a shift towards performing more oncologic...

The most common irAEs are skin effects, but other common manifestations involve the gastro-intestinal tract, liver, lungs, endocrine glands and joints [2,3,6]. The most common irAEs in which imaging can play an important role are pneumonitis, colitis and hypophysitis [2,4]. Pneumonitis Pneumonitis is the most common irAE in the chest. It mostly manifests itself in one of the following 4 patterns: cryptogenic organizing pneumonia (COP) (figure 1), non-specific interstitial pneumonia (NSIP)(figure 2), hypersensitivity pneumonitis (HP)(figure 3) and acute interstitial pneumonia/acute respiratory distress syndrome (AIP/ARDS) [1,3,11]...

Imaging plays an integral role in cancer care and the use of ICIs is increasing. It is important for the radiologist to be aware of the imaging findings of irAEs, in order to distinguish these from disease progression and to ensure prompt timely clinical management.

Kalisz KR, Ramaiya NH, Laukamp KR, et al. Immune Checkpoint Inhibitor Therapy-related Pneumonitis: Patterns and Management. Radiographics. 2019 Nov-Dec;39(7):1923-1937. Wang GX, Kurra V, Gainor JF, et al. Immune Checkpoint Inhibitor Cancer Therapy: Spectrum of Imaging Findings. Radiographics. 2017 Nov-Dec;37(7):2132-2144. Costa LB, Queiroz MA, Barbosa FG, et al. Reassessing Patterns of Response to Immunotherapy with PET: From Morphology to Metabolism. Radiographics. 2021 Jan-Feb;41(1):120-143. Nishino M, Hatabu H, Hodi FS. Imaging of Cancer Immunotherapy: Current Approaches and Future Directions. Radiology. 2019 Jan;290(1):9-22. Lasocki A, Iravani A, Galligan...