Thread by @DrTeresaMC

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You're on call and open a chest CT for a patient with suspected #COVID19.

How do you interpret and report the imaging findings?

A #TWEETORIAL of the @Radiology_RSNA Expert Consensus Statement on Reporting Chest CT Findings Related to COVID-19

pubs.rsna.org/doi/10.1148/ry…

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This consensus statement has been endorsed by @thoracicrad and @RadiologyACR.

Important work by our faculty @PennRadiology Drs. Scott Simpson & Harold Litt.
Podcast: rsnaradiologycti.libsyn.com/welcome-to-the…

*Figures/tables in this #tweetorial from orig. manuscript, unless otherwise stated.

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🔑KEY POINT:

☝️First, it’s important to note that routine screening chest CT for identification of #COVID19 is NOT currently recommended by most professional organizations.

@CDCgov Guidance:
cdc.gov/coronavirus/20…

@RadiologyACR Recommendations:
acr.org/Advocacy-and-E…

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While not recommended for screening, the # of chest CTs performed in persons under investigation (PUI) for #COVID19 has ⬆️

The authors also anticipate that patients will have incidental findings on imaging performed for unrelated reasons which may be attributable to #COVID19

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Here’s a look at #COVID19 cases & deaths in the United States by State as of 5/30/2020

And a look at confirmed cases & deaths for the 10 countries with the highest absolute number of deaths, including the US (dark green).

Figure sources: @CDCgov and @JohnsHopkins

Should you include "COVID-19" in the radiology report of a patient with chest CT findings potentially attributable to #COVID19 pneumonia?

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The authors propose 4 categories for reporting CT imaging findings related to #COVID19 with suggested standardized reporting language.

1) Typical appearance
2)Indeterminate appearance
3)Atypical appearance
4)Negative for pneumonia

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🔑KEY POINT:

Categories & reporting language do not reflect likelihood of #COVID19 infection, which depends on factors like prevalence, exposure, risk factors & presentation.

They indicate CT findings reported in the literature, and their typicality in #COVID19 pneumonia.

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Now, let’s discuss the #typical chest CT imaging findings of #COVID19

🔘Bilateral
🔘Ground-glass opacities aka GGOs (round or “crazy-paving” morphology common)
🔘+/- consolidation
🔘Peripheral, posterior distribution
🔘Diffuse or lower lung predominance

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#Typical Cases

Here’s a patient with positive RT-PCR and #typical imaging features of #COVID19 showing bilateral, multifocal, rounded (asterisks), and peripheral GGO (arrows) with superimposed interlobular septal thickening and visible intralobular lines (“crazy paving”).

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🔑KEY POINT:

Chest CT findings can precede positivity on RT-PCR.

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While these findings are #typical for #COVID19, what other causes/diseases should be in your differential?

🔘Influenza A
🔘Organizing pneumonia (idiopathic or secondary to drug toxicity or connective tissue disease)
🔘Other viral pneumonias

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What imaging features would be considered #indeterminate for #COVID19?

🔘Non-rounded, non-peripheral GGO
🔘Lack of specific distribution
🔘Can be multifocal, diffuse, perihilar, or unilateral
🔘+/- consolidation

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#Indeterminate Cases:

Patchy GGO with non-rounded morphology and without specific distribution in two patients.

🔘(A,B): Patient with #COVID19 pneumonia
🔘(C,D): Patient with acute lung injury from presumed drug toxicity.

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#Indeterminate Cases:

Diffuse GGO without specific distribution & with non-rounded morphology in two different patients.

🔘Patient A: findings were the result of acute lung injury from presumed drug toxicity
🔘Patient B: findings were the result of Pneumocystis pneumonia.

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Next, let’s cover #atypical chest CT imaging findings of #COVID19:

🔘Isolated lobar or segmental consolidation
🔘Small nodules (i.e. centrilobular, “tree-in-bud”)
🔘Lung cavitation
🔘Smooth interlobular septal thickening with pleural effusion

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#Atypical Cases:

Here we have two patients with #atypical chest CT findings for #COVID19

A: Right lung cavitation (arrow) in a pt with Klebsiella pneumonia
B: Left lung cavitation (arrow) and tree-in-bud opacities (circle) in a pt w/ nontuberculous mycobacterial infection

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The last category - #negative for pneumonia - implies that there are no chest CT abnormalities that could be attributable to #COVID19.

Does a negative chest CT exclude the possibility of #COVID19?

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🔑KEY POINT

There may be no findings on chest CT in the early stages of #COVID19 infection.

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Now, it's time to generate our #radiology report.

How should we report the findings?

The authors:
🔘Make the case for structured reporting
🔘Propose standardized language
🔘Cover the pros and cons of standardized reporting for chest CT findings related to #COVID19.

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SCENARIO:

You practice in a #COVID19 endemic area, and while interpreting a patient’s chest CT for lung cancer surveillance, you incidentally note findings typical of #COVID19.

What should you do next?

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The authors recommend direct communication with the referring provider to discuss likelihood of viral infection and reach consensus.

When noted incidentally, findings do not need to be reported as #COVID19 pneumonia, and “viral pneumonia” is a reasonable alternative.

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💥TAKE HOME POINT # 1

The goal of this expert consensus is to help #radiologists recognize & report imaging findings of #COVID19 pneumonia.

But remember, consultation with clinical colleagues at your institution is key to establishing an agreed upon reporting approach.

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💥TAKE HOME POINT # 2

Despite most professional guidelines recommending against routine screening CT for #COVID19, chest CTs may be requested for diagnosis & management, particularly when RT-PCR is not readily available.

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💥TAKE HOME POINT # 3

Standardized chest CT reporting language can provide a consistent reporting framework, improve clarity and reduce variability when reporting chest CT findings related to #COVID19.

@threadreaderapp @covid19threads

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