COVID-19 IMAGING AND FINDINGS

Hello, Permission to share covid19 imaging, hopefully we will all be safe from covid19. let's take care of health, get enough rest, and consume healthy food.

Points learned include :

1. Introduction
2. Clinical Features
3. PCR-test
4. Chest CT
5. Ground glass
6. Crazy paving
7. Vascular dilatation
8. Traction Bronchiectasis
9. Subpleural bands and Architectural distortion
10. CT involvement score
11. Initial CT-findings
12. Changes over time
13. CT Report
14. Chest radiograph
15. Possible role of CT
16. Video cases of CT Chest

Introduction

Clinical Features

COVID-19 usually presents with fever (85%), cough (70%) and shortness of breath (43%), but abdominal and other symptoms are possible and the disease can be asymptomatic.

Overal mortality rate is 2.3% in some series of patients who had a positive test for COVID-19.

Since we do not know the number of people who were infected but not tested for the virus, the actual mortality rate of all the people that are infected is probably much lower.

Illness severity can vary from mild to critical.

Mild: no symptoms, mild caughing and fever.

Severe: dyspnea, hypoxia or > 50% lung involvement on imaging.

Critical: respiratory failure, shock, multi-organ failure.

PCR-test

The PCR-test is very specific, but has a lower sensitivity of 65-95%, which means that the test can be negative even when the patient is infected. Another problem is, that you have to wait for the test results, which can take more than 24 hours, while CT results are available right away.

Common laboratory findings in COVID-19 are a decreased lymphocyte count and an increased CRP and high-sensitivity C-reactive protein level.

Chest CT

Ground glass
Ground glass (GGO) pattern is the most common finding in COVID-19 infections.
They are usually multifocal, bilateral and peripheral, but in the early phase of the disease the GGO may present as a unifocal lesion, most commonly located in the inferior lobe of the right lung.
CT-images of a young male, who had fever for ten days with progressive coughing and shortness of breath.
Saturation at admission was 66%.
The PCR test was positive for COVID-19.
There are widespread bilateral ground-glass opacities with a posterior predominance.

Crazy paving
Sometimes there are thickened interlobular and intralobular lines in combination with a ground glass pattern. This is called crazy paving. It is believed that this pattern is seen in a somewhat later stage.

Vascular dilatation
A typical finding in the area of ground glass is widening of the vessels (arrow).

Traction Bronchiectasis
Another common finding in the areas of ground glass is traction bronchiectasis (arrows).

Subpleural bands and Architectural distortion
CT involvement score
The severity of the lung involvement on the CT correlates with the severity of the disease.
Visual assessment
The severity on CT can be estimated by visual assessment.
This is the easiest way to score the severity.
The CT images show a 25% involvement by visual assessment.
Severity score
Another method is by scoring the percentages of each of the five lobes that is involved:
< 5% involvement
5%-25% involvement
26%-49% involvement
50%-75% involvement
> 75% involvement.
The total CT score is the sum of the individual lobar scores and can range from 0 (no involvement) to 25 (maximum involvement), when all the five lobes show more than 75% involvement.
Some say that the percentage of lung involvement can be calculated by multiplying the total score times 4.
This however is not true. Suppose that all lobes have a 10% involvement, then this would lead to an overall score of 10, which could lead to the impression that 40% of the lungs are involved.

Initial CT-findings
Initial CT-findings in COVID-19 cases include bilateral, multilobar groud glass opacification (GGO) with a peripheral or posterior distribution, mainly in the lower lobes nd less frequently in the middle lobe.
Consolidation superimposed on GGO as the initial imaging presentation is found in a smaller number of cases, mainly in the elderly population.
Septal thickening, bronchiectasis, pleural thickening, and subpleural involvement are some of the less common findings, mainly in the later stages of the dis- ease.
Pleural effusion, pericardial effusion, lymphadenopathy, cavitation, CT halo sign, and pneumothorax are some of the uncommon but possible findings seen with disease progression.
There is much overlap of the CT-pattern of COVID-19 with other viral pneumonias.

Images of a 59 year old male who had fever for one week with non-productive cough.

The PCR-test was negative.

Because of clinical suspicion a CT was performed which showed some areas of GGO and massive consolidation in the posterior parts of the lower lobes (arrow on sagittal reconstruction).

Two days later a sputum test was positive for COVID-19.

Changes over time
Advanced-phase disease is associated with a significantly increased frequency of:
GGO plus a reticular pattern (crazy pavin)
Vacuolar sign
Fibrotic streaks
Air bronchogram
Bronchus distortion
Subpleural line or a subpleural transparent line

Pleural effusion

This 59 year old female had a history of ten days of fever and five days of coughing.

The O2 saturation was 89 and her respiratory rate was 30/min (normal: 12-18).

There are widespread GGO's without consolidation. No architectural distortion.

This was reported as early phase COVID-19.

These images are of a 49 year old male with fever, cough and a low saturation.

The images show:

Bilateral areas of GGO.

The ground glass density is more pronounced

Fibrotic bands (arrows).

Dilated vessels in affected area (circle).

Based on the CT-findings COVID-19 infection was assumed to be highly likely - late phase.

This patient had fever for one week with some abdominal pain and diarrhoea.

On the day of admission she had a dry cough and complained of dizziness.

The O2-saturation was low.

The PCR-test was not known and a CT was performed for triage.

The images show:

Bilateral subpleural GGO's 

Consolidation in right lower lobe with traction bronchiectasis (green arrow).

Fibrous bands (yellow arrow).

Based on the CT-findings COVID-19 infection was assumed to be highly likely - late phase.

CT Report
In the tabel a checklist of CT findings to mention in the report.
In the first four days after the presentation of the complaints, the CT is not sensitive as initial test as 50% of patients may have a normal CT.
After these first four days, the CT has a very high sensitivity.

COVID-19 Standard Report CT click Next

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