Atypical chest CT findings of COVID-19 pneumonia: a pictorial review

Abstract

Coronavirus disease 2019 (COVID-19) first emerged in China and rapidly spread in the world causing a pandemic. Chest computed tomography (CT) continues to play an important role in the diagnosis and follow-up of the disease due to shortcomings of the real-time reverse transcription-polymerase chain reaction test, which is the gold standard in the diagnosis of this disease. Typical chest CT findings of COVID-19 pneumonia have been widely reported in the literature. However, atypical findings such as central involvement, peribronchovascular involvement, isolated upper lobe involvement, nodular involvement, lobar consolidation, solitary involvement, pleural and pericardial fluid, and subpleural sparing can also be seen. Knowing these atypical findings is important to avoid misdiagnosis. This review summarizes the atypical findings that can be seen in the course of the disease and may be confused with other diseases.

Figure 1

Axial CT image of a 60-year-old male patient with confirmed COVID-19 pneumonia presenting with fever and cough shows irregular consolidation and GGO in central areas of both lungs. Bilateral pleural effusion is also seen (arrows).

Figure 2

Axial CT image of a 40-year-old female COVID-19 pneumonia patient shows crazy-paving pattern in central peribroncovascular area of right upper lobe (arrows).

Figure 3. a, b

CT images of a 24-year-old COVID-19 pneumonia patient with isolated upper lobe involvement. Axial (a) and coronal reformatted (b) images show GGOs with consolidation in the right upper lobe (arrows). Right lower lobe and left lung are entirely normal.

Figure 4

A 46-year-old male COVID-19 patient presenting with fever and dry cough for 8 days. Axial CT image shows a single solid nodule surrounded by a ground-glass halo in the left upper lobe (arrow).

Figure 5. a, b

Axial CT images of a 34-year-old male COVID-19 patient presenting with fever and dry cough for 3 days. Image (a), taken at presentation, shows a small subpleural nodular GGO in the left lower lobe (arrow). Image (b), taken one week later, shows an enlarged region of GGO with superimposed consolidations in both lower and middle lobes (arrows).

Figure 6. a, b

CT images of a 52-year-old COVID-19 pneumonia patient with atypical involvement. Axial (a) and coronal reformatted (b) images show GGO along peribronchovascular bundle from the central area to the periphery of the left upper lobe (arrows).

Figure 7. a, b

Axial CT images (a, b) of a 47-year-old male patient with confirmed COVID-19 pneumonia presenting with fever and cough show isolated lobar consolidation in the left upper lobe (arrows).

Figure 8. a, b

A 51-year-old female COVID-19 pneumonia patient. Axial (a) and sagittal reformatted (b) CT images show round consolidation (arrows) in the right lower lobe.

Figure 9

Axial CT image of a patient with positive RT-PCR test shows tree-in-bud pattern in the right lower lobe (arrows).

Figure 10

Axial CT image of a 44-year-old man with COVID-19 pneumonia shows two nodules in the left upper lobe (arrows).

Figure 11. a, b

CT images of a 57-year-old patient with mild symptoms of COVID-19 pneumonia. Axial image (a) demonstrates left-predominant bilateral pleural effusion (mediastinal window). Image (b) shows peripheral GGOs in the right upper lobe (arrows).

Figure 12. a, b

CT images of a 63-year-old patient with moderate symptoms of COVID-19 pneumonia. Axial image (a) demonstrates pericardial effusion on mediastinal window settings (arrows). Image (b) shows bilateral GGOs in both lower lobes (arrows).

Figure 13. a, b

A 47-year-old patient with COVID-19 pneumonia. Axial (a) and sagittal reformatted (b) CT images show extensive peripheral consolidation with GGOs in the right lower lobe. The subpleural area appears protected (arrows).

Figure 14

A 74-year-old male COVID-19 patient presenting with fever, chills and cough for 5 days. Axial CT scan shows bilateral extensive consolidations. The patient died 10 days later.

Figure 15

Axial CT image of a 59-year-old patient with moderate symptoms of COVID-19 pneumonia shows diffuse GGOs in both lungs.

Figure 16

A 63-year-old male patient with confirmed COVID-19 pneumonia presenting with fever and dry cough. Axial CT image shows combined pulmonary fibrosis and emphysema findings in both lungs (white arrows). There is also peripheral GGO in the fibrosis area in the left lower lobe (yellow arrows).

Figure 17

Axial CT image of a 74-year-old patient with confirmed COVID-19 pneumonia shows extensive emphysema in both lungs. There is also irregular consolidation in both lower lobes, mimicking nonspecific bronchopneumonia (yellow arrows).

Figure 18. a, b

Contrast-enhanced CT scan of a 41-year-old female patient with COVID-19 pneumonia. Axial image (a) shows pulmonary embolism in the branches of the right and left pulmonary arteries (yellow arrows) on mediastinal window settings. Peripheral infarction due to embolism (white arrows) is seen on mediastinal (a) and lung window (b) settings.

Figure 19. a, b

Axial image (a) shows the focus of fungal pneumonia (yellow arrow) developing after neutropenia in a patient with chronic lymphocytic leukemia. Bilateral pleural effusion (white arrows) is also seen. One week later, the patient was diagnosed with COVID-19 pneumonia and newly developed peripheral GGOs are observed in follow-up CT (b, thick yellow arrows).