Examples of cases for which there was significant disagreement in assignment of RSNA consensus COVID-19 category.
A) 67-year-old man with clinical signs of pneumonia and 4 negative PCRs for COVID-19 with sputum samples positive for streptococcus pneumoniae. Axial CT image shows a combination of tree-in-bud centrilobular nodules in the lower lobes and peripheral ground glass opacity and consolidation in the left lower lobe. Categories 3, 2, and 1 were assigned by 4, 3, and 2 readers respectively.
B) 23-year-old man with 2 negative PCR results for SARS-CoV-2 and presumed aspiration or non-23-COVID-19 infection. Axial CT image shows minimal patchy ground glass opacities in the left lower lobe; there was a question of atelectasis or subtle peripheral ground glass opacity in the posterior right lower lobe. Categories 3, 2, 1, and 0 were assigned by 1, 6, 1, and 1 readers respectively.
C) 64-year-old woman with PCR-proven COVID-19 pneumonia who presented with fever, productive cough, fatigue, and anosmia. Axial CT image shows patchy ground glass opacities in the lingula and a small amount of peripheral ground glass opacity and atelectasis in the posterior lower lobes. Categories 3, 2, 1, and 0 were assigned by 4, 3, 1, and 1 readers respectively. Reasons given by readers for uncertainty included doubts about peripheral distribution, and difficulty in classification in the setting of minimal disease and posterior atelectasis.
D) 65-year-old woman with PCR-proven COVID-19 pneumonia who presented with palpitations, back pain, and low-grade fevers. Axial CT image shows patchy ground glass opacities bilaterally. Categories 3 and 2 were assigned by 5 and 4 readers respectively. Reasons given by readers for uncertainty included difficulty in classifying as peripheral or diffuse and questionable morphology of the ground glass opacities.