Fig. 2

a–g COVID-19 pneumonia differential diagnosis: infective pneumonia. HRTCs of infective pneumonias. In a, S. Pneumoniae lobar pneumonia shows consolidations with air bronchogram (black arrowheads in a), while in b, atypical pneumonia presents as multiple nodular (white arrow in b), tubular (white bordered black arrow in b) consolidative foci and centrilobular nodules (white circle in b). In c, HRTC showing centroparenchymal ground-glass opacities (black arrows in c) in patient affected by Influenza type A pneumonia. Patients affected by HIV and pneumocistis jiroveci pneumonia in d and e, and presenting with bilateral, widespread crazy paving and ground-glass opacities on HRTC during acute pneumonia and perihilar pneumatoceles (white arrows in e) with pleural effusions in a long-lasting pneumonia. HRCTs of patient affected by angioinvasive aspergillosis at baseline (f) and after 7 days (g). At baseline, two consolidations rimmed by ground-glass halo are evident in f (white arrow in f, halo sign), while after therapy, excavated nodules showing “air crescent sign” (black arrow in g) indicate the remission phase