대한흉부영상의학회 Weekly Chest Cases

KSR/KSTR Guidelines for the use of Diagnostic imaging for COVID-19 / Q&A for radiologists on COVID-19

KSTR ADMIN
2020-04-10 13:43

The Korean Society of Radiology and the Korean Society of Thoracic Radiology have prepared recommendations for the use of diagnostic imaging for COVID-19 in various clinical scenarios. We have tried to grasp the situation in the real world, aggregated opinions from the chest radiologists, and reviewed available references, in order to suggest the most reasonable recommendations possible at this moment. As circumstances change and new evidences emerge, the recommendations should immediately be modified accordingly.

* You can find the full Korean and English versions of the recommendations at the link below.

==> https://jksronline.org/DOIx.php?id=10.3348/jksr.2020.81.e21

* For your convenience, a condensed copy has also been posted below with accompanying FAQs.

The Role of Imaging Studies (Chest Radiography, Chest CT) as Screening Tests for COVID-19

1. Screening with chest radiography (CXR) or chest CT is not recommended for asymptomatic individuals visiting COVID-19 screening clinics* for epidemiological or other unspecified reasons.

2. CXR may be considered in patients with respiratory symptoms visiting COVID-19 screening clinics for an early diagnosis of pneumonia or to rule out diseases other than COVID-19.

3. CXRs are recommended for patients with fever or respiratory symptoms visiting outpatient safe clinics†. However, the use of CXRs to rule out COVID-19 pneumonia is not recommended.

4. Chest CT can be done, after weighing individual risks and benefits, in these circumstances: 1) when pneumonia is suspected clinically although pneumonia is not definite on CXR, 2) when there is a high clinical suspicion for COVID-19 but with negative reverse transcription polymerase chain reaction (RT-PCR) results 3) critically ill patients or patients with other diseases who are in need of emergent operations or procedures who cannot wait for RT-PCR results.

Non-contrast chest CT is recommended, but contrast-enhanced chest CT may be considered when complications or other diseases are suspected.

Guidelines for the Use of Diagnostic Imaging for COVID-19 Patients in Community Treatment Centers for Isolation

1. CXRs may be considered when asymptomatic patients or patients with mild symptoms are admitted to community treatment centers^‡, as a reference for future follow-ups.

2. Follow-up CXRs may be performed in patients isolated in community treatment centers, after considering the changes in clinical manifestations of the patient and available resources and manpower for imaging studies.

3. When CXRs are performed in community treatment centers, portable X-ray machines or screening buses may be appropriate. A thorough image quality control should be done to maintain images of diagnostic quality, and appropriate measures for radiation protection and safety should be taken, complying with all relevant quality control regulations. For follow-up purposes, it is recommended to perform exams of a same patient using the same machine used for the initial exam.

4. Interpretation of the imaging studies should be done by experienced doctors, and interpretation or consultation by board-certified radiologists is recommended.

5. When pulmonary infiltrations develop on CXRs performed in community treatment centers, the patients need close clinical monitoring and admission to hospitals may be considered.

6. For the safety of medical personnel and prevention of the disease spread, avoid contact with patients if possible, and regular cleaning and disinfecting of equipment should be done.

Guidelines for Imaging Studies for Admitted Patients with COVID-19

1. Imaging follow-up with CXR is recommended for the patients with pneumonia.

2. When complications are suspected, chest CT may be considered, after considering the potential risks and benefits.

Definition

^*Screening clinics: for individuals who have a history of visiting a foreign or dangerous area/dangerous place with or without fever or respiratory symptoms.

^†Outpatient safe clinics: for patients with fever/respiratory symptoms but without clinical or epidemiological suspicion for COVID-19.

^‡Community treatment centers: for patients with asymptomatic or mild symptoms identified with COVID-19 through RT-PCR.

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Q&A for radiologists on COVID-19

We have prepared a set of short questions and answers on COVID-19, which might appear during the clinical process. Many of the following questions have come up during the 2015 Middle East Respiratory Syndrome (MERS) outbreak in Korea, and the questions have been modified for COVID-19 pneumonia. The answers for the questions have been prepared with reference to many studies and reports on COVID-19 as of March 2020.

Q. What is the role of chest imaging in the diagnosis of COVID-19?

The diagnosis of COVID-19 is confirmed by RT-PCR (reverse-transcription polymerase chain reaction) of the patient’s samples, and the chest imaging findings are not in the diagnostic criteria of COVID-19 at the moment. However, after its transition to community transmission, chest imaging can be used for the examination of presence of pneumonia in suspected patients and monitoring and prognostication of confirmed patients (1,2).

Q. Should chest CT be additionally performed in a patient with suspected COVID-19 infection whose chest x-ray is normal?

Sensitivity of chest CT is very superior to that of CXR in the diagnosis of pneumonia in COVID-19 patients. According to the reports in Korea, only 30% of the confirmed COVID-19 cases showed positive CXR results in early phase of disease (3).

Q. What are typical chest CT findings of COVID-19 pneumonia?

Chest CT findings of the COVID-19 pneumonia can be divided into 1) early phase and 2) advanced phase (4,5). In early phase, bilateral subpleural ground-glass opacities in the basal lungs are typically seen. However, in early phase, chest CT may be normal even with positive RT-PCR results (6). In advanced phase, the damage to the lung parenchyma becomes more prominent, with consolidation and traction bronchiectasis.

Q. What are chest CT findings of COVID-19 pneumonia that are related to the prognosis of the disease?

If the extent of ground-glass opacity is larger in early phase after symptom onset, the pneumonia tends to aggravate, unresponsive to treatment (7).

Q. Are there differences in chest CT findings of pediatric and adult COVID-19 pneumonia cases?

In pediatric patients, COVID-19 pneumonia can be superimposed with pneumonia caused by other types of pathogens. COVID-19 pneumonia typically manifests as subpleural ground-glass opacities, similar to adult patients. However, consolidations with surrounding halo sign account for up to 50% of the cases in the pediatric patients, higher than that of the adult patients (8).

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대한흉부영상의학회 Korean Society of Thoracic Radiology

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KSR/KSTR Guidelines for the use of Diagnostic imaging for COVID-19 / Q&A for radiologists on COVID-19