COVID-19 pneumonia-ultrasound, radiographic, and computed tomography findings: a comprehensive pictorial essay

Abstract

Ultrasound, chest X-ray, and computed tomography (CT) have been used with excellent results in diagnosis, first assessment, and follow-up of COVID-19 confirmed and suspected patients. Ultrasound and chest X-ray have the advantages of the wide availability and acquisition at the patient's bed; CT showed high sensitivity in COVID-19 diagnosis. Ground-glass opacities and consolidation are the main CT and X-ray features; the distribution of lung abnormalities is typically bilateral and peripheral. Less typical findings, including pleural effusion, mediastinal lymphadenopathies, the bubble air sign, and cavitation, can also be visible on chest CT. Radiologists should be aware of the advantages and limitations of the available imaging techniques and of the different pulmonary aspects of COVID-19 infection.

Keywords: COVID-19; Coronavirus; Pneumonia, viral; Severe acute respiratory syndrome coronavirus 2; Tomography, spiral computed.

Fig. 1

Chest US (a) of a COVID-19 patient showing more than 3 B lines (arrows) visible as vertical hyperechoic artifacts originating from the pleural line. Posterobasal chest US scan (b) of a COVID-19 patient showing a peripheral lung consolidation (arrows)

Fig. 2

Chest X-rays of two confirmed cases of COVID-19 infection, showing the bilateral presence of GGO (frames). In (a), the distribution is mainly peripheral, whereas in (b), the abnormalities have both peripheral and central distribution in the right lung. In the upper left field (b), some small consolidations are also present

Fig. 3

Examples of consolidations (frames) in two confirmed cases of COVID-19 infection. In (a), the chest radiograph of a 65-year-old man with cough and fever for 7 days, showing bilateral patchy consolidations. In (b), the chest radiography of a 63-year-old man with cough and fever from 12 days, admitted to the intensive care unit showing extensive bilateral consolidation with a prevalent peripheral location in the lower lung zones

Fig. 4

Changes in lung abnormalities during the disease. Chest X-ray of a 58-year-old man executed on March 18 (a) and on March 30 (b). The first X-ray was acquired at 2 days from the onset of the symptoms and showed bilateral mainly peripheral GGO, and small patchy consolidation in the left upper field. X-ray following at 12 days showed reduced expansion of the pulmonary fields, with the worsening of the abnormalities and evidence of bilateral consolidation and left pleural effusion (white arrows)

Fig. 5

Chest X-ray (a) and coronal reconstruction of the unenhanced CT of a 58-year-old COVID-19 male patient admitted to the ICU showing bilateral diffuse airspace opacities and the presence of oval areas of hyperlucency corresponding at CT to cavitation (frames)

Fig. 6

Unenhanced chest CT scans showing some examples of GGO (frames) in COVID-19 patients. In (a), the abnormality is in the right lower lobe posteriorly; in (b), GGO are bilaterally recognizable, with peripheral and peri-broncho-vascular distribution. In (c), the GGO are patchy, with bilateral involvement of the lower lobes

Fig. 7

Examples of lung consolidations (frames) in COVID-19 patients. In (a), the consolidation is associated with GGO (white arrow) and crazy paving pattern (thin arrows); in (b), the consolidations are patchy, with peripheral posterior location; patchy GGO are also present (arrows). In (c), the consolidations are bilateral and confluent

Fig. 8

Unhenanced chest CT of 65-year-old COVID-19 patient admitted to ICU. The tracheal cannula has been wrongly positioned in the right bronchus. Bilateral evidence of extensive airspace abnormalities, with peripheral posterior consolidations and crazy paving pattern and concomitant air bronchogram sign (frame)

Fig. 9

Examples of reticular patterns in COVID-19 male patients (a 53-year-old, b 63-year-old) showing reticular pattern (frames) with the bilateral peripheral distribution

Fig. 10

Chest CT of a 48-year-old patient showing bilateral peripheral linear opacities with course parallel to the pleural surface (frames). A small nodule with peripheral GGO, resulting in a halo sign is present in the lower left lobe (white arrow)

Fig. 11

Chest CT of a 63-year-old COVID-19 patient. In the left lower lobe, posteriorly, a small air-filled cavity in the context of lung consolidation is present (frame). This is the “air bubble sign.” Areas of the reticular pattern are bilaterally recognizable

Fig. 12

Chest CT of a 73-year-old COVID-19 patient, showing a bilateral diffuse reticular pattern of abnormalities; in the left lower lobe, posteriorly, cavitation is visible as an air-filled component including a fluid level (frame)

Fig. 13

Pre-discharge chest CT of a COVID-19 male patient, at 27 days from the onset of the symptoms. Bilateral linear opacities are recognizable (white arrows)

Fig. 14

Coronal reconstruction of the pre- (a) and post-discharge CT a 75-year-old COVID-19 patient. The first CT (a), executed on April 15, at 30 days from the onset of the symptoms, showed bilateral irregular linear opacities and peripheral consolidations. The follow-up CT, performed on June 24, showed bilateral extensive faded GGO in the location of the previous abnormalities. This can be defined as a “tinted sign”