A 63-year-old man presented with cough, dyspnea, and fever (38ºC). His respiratory rate was 20 breaths/min and arterial oxygen saturation was 91% on room air. Past medical history in­cluded diabetes mellitus, hyperlipidemia, and hepatitis B infection. He was admitted to the intensive care unit but not intubated.

Chest X-ray performed on admission showed mild nonspecific increased bronchovascular markings with no consolidation (Figure 1A).

Figure 1. Patient with coronavirus disease 2019 (COVID-19): A – chest X-ray on admission showing mild nonspecific increased bronchovascular markings; BG – chest computed tomography showing abnormalities commonly seen in COVID-19 pulmonary infection (white arrows indicate ground-glass opacities and blue arrows areas of parenchymal consolidation)

Because the patient’s oxygen saturation was decreasing, computed tomography (CT) was performed (Figure 1B-1G). The lung parenchyma was inhomogeneous with bilateral patchy ground glass opacities along with areas of consolidations. The abnormalities had a peripheral distribution and were more extensive in the lower lobes. There was no pleural effusion or lymphadenopathy.

The diagnosis of coronavirus disease 2019 (COVID-19) pulmonary infection was established. The patient was treated with oseltamivir, ritonavir, hydroxychloroquine, and vancomycin.

The hospitalization lasted 15 days and the patient was discharged in stable condition with oxy­gen saturation of 95%.

The important common features of COVID-19-induced pulmonary lesions on CT of the thorax include, in the early till late stages, the following 3 key abnormalities1: 1) ground glass opacities with peripheral distribution, 2) consolidations with peripheral distribution, 3) multifocal/multilobar involvement.

Late findings of COVID-19 include: 1) linear opacities, 2) crazy-paving (used to describe ground-glass opacities with superimposed interlobular and intralobular septal thickening), 3) reverse halo.

Additional inconsistent findings in COVID-19 infections are2: 1) tree-in-bud nodularity, 2) centrilobular distribution, 3) predominantly peribronchovascular pattern of distribution, 4) predominantly nodular pattern, 5) cavitation, 6) lymphadenopathy, 7) pleural effusion.

Patients who are at a higher risk for severe illness caused by COVID19 are older adults (>65 years), patients with underlying HIV, asthma, and possibly pregnant women.3

The most important criteria for COVID-19 severity are respiratory distress (respiratory rates ≥30, arterial oxygen saturation <93% at rest, ratio of partial pressure arterial oxygen to fraction of inspired oxygen [PaO2/FiO2] ≤300 mm Hg), and rapid (within 24–48 hours) progression (>50%) of CT findings. Disease progression can lead to res­piratory failure, shock, and extra pulmonary organ failure.4

To summarize, CT of the thorax is sensitive enough to detect the viral infection (COVID-19) but should not be used as a screening tool in asymptomatic patients. Computed tomography is important to differentiate and rule out other chest findings which may mimic COVID-19 and plays a vital role in the monitoring of disease progression.