COVID-19 Pneumonia

C. R. Pontes, RT; R. S. Silva, BS; P. Bertolazzi, BS*; M. B. Damaceno, MD
Radiology Department, Brasil Laudos, Sao Luiz Hospital, Boituva, SP, Brazil
*Siemens Healthineers, Brazil
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A 42-year-old female patient (BMI 32.4), suffering from fever (37.8º C) and a moderate dry cough for the past week, presented herself to the hospital. She was a non-smoker and had an unremarkable past medical history. The RT-PCR test for COVID-19 resulted positive and she was then referred for a chest CT examination.

CT images revealed multiple ground-glass opacities (GGO), with partial consolidation, affecting multiple lobes in both lungs. The lesions’ distribution was predominantly subpleural, posterior and peripheral, however bilateral central involvement was also seen. Additional findings such as septal thickening, pleural thickening, bronchial wall thickening, air bronchogram and bronchus distortion were also visualized. There were no signs of adenopathy or similar processes. The aorta and pulmonary arteries were unremarkable. Considering all clinical and epidemiological data, CT findings were consistent with the diagnosis of COVID-19 pneumonia.

Peripheral and central distribution of patchy GGO bilaterally in the lungs and pleural thickening
Courtesy of Radiology Department, Brasil Laudos, Sao Luiz Hospital, Boituva, SP, Brazil

Fig. 1:
Axial images (4 mm) show both peripheral and central distribution of patchy GGO bilaterally in the lungs. Pleural thickening is also seen (Fig. 1a, arrow).

COVID-19 pneumonia is a viral infectious disease caused by a novel coronavirus (SARS-CoV-2). It is highly contagious, leading to a wide involvement of the global population and is currently a World Health Organization (WHO) declared pandemic. A chest CT examination is performed to assist diagnosis and assess complications. The primary CT findings include GGO and/or air space consolidation that can be bilateral, peripheral or basal in distribution. Image noise is usually well-tolerated when visualizing such patchy lesions in the lungs. Therefore, scanning with a lower radiation dose has great potential. In this case, we performed the CT scan with a low dose protocol using SOMATOM go.Now. The exposure reduction is enabled by an advanced tin filter technology, which optimizes the X-ray spectra and significantly improves the air / tissue contrast. The achieved image quality is considered to be optimal for diagnosis. This protocol should also be considered for follow-up scans. The acquired images can be reconstructed in multiplanar reconstruction (MPR), and volume rendering technique (VRT) to enhance the visualization of the lesions.

Multiple GGO in all lobes of both lungs. Signs of bronchial wall and septal thickening of the right horizontal fissure
Courtesy of Radiology Department, Brasil Laudos, Sao Luiz Hospital, Boituva, SP, Brazil

Fig. 2:
A coronal MPR image (Fig. 2a, 3 mm) and a VRT image (Fig. 2b) show multiple GGO in all lobes of both lungs. Signs of bronchial wall thickening (Fig. 2a, arrowheads) and septal thickening (Fig. 2a, arrow) of the right horizontal fissure are clearly seen.

Air bronchogram and bronchus distortion in patchy GGO with partial consolidation in the superior lobe. Multiple vacuoles inside patchy GGO in the inferior lobe.
Courtesy of Radiology Department, Brasil Laudos, Sao Luiz Hospital, Boituva, SP, Brazil

Fig. 3:
A sagittal MPR image of the right lung (Fig. 3a, 2 mm) shows air bronchogram (arrow) and bronchus distortion (arrowhead) in patchy GGO with partial consolidation in the superior lobe. A sagittal MPR image of the left lung (Fig. 3b, 2 mm) shows multiple vacuoles inside patchy GGO in the inferior lobe (circle).

Scanner

Scan area

Thorax

Scan mode

Spiral

Scan length

329 mm

Scan direction

Caudo-cranial

Scan time

24 s

Tube voltage

Sn110 kV

Effective mAs

121 mAs

Dose modulation

CARE Dose4DTM

CTDIvol

1.99 mGy

DLP

67.1 mGy cm

Rotation time

0.8 s

Pitch

1.0

Slice collimation

16 x 0.7 mm

Slice width

1.5 mm

Reconstruction increment

1.0 mm

Reconstruction kernel

Br40 / Br60