Suraj Sah
Background
Novel Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The first cases were seen in Wuhan, China in December 2019 before spreading globally. The current outbreak was recognized as a pandemic on 11 March 2020. COVID-19 has mean incubation period of 5.2 days. COVID-19 which is viable up-to 24 hours on dry surfaces are mainly transmitted through the large droplets and direct inoculation.
Radiologic aspects of COVID-19
For the initial diagnostic testing for the suspected COVID-19 infection, the Center for Disease Control (CDC) recommends collecting and testing specimens from the upper respiratory tract (nasopharyngeal and oropharyngeal swabs) or from the lower respiratory tract when available for viral testing.Due to the limited availability of viral (COVID-19) testing kit to date, there is growing concern for test sensitivity. The CDC does not currently recommend Chest X-ray or CT scan to diagnose COVID-19. Viral testing remaining only specific methods of diagnosis. Confirmation with the viral test is required, even if radiologic findings are suggestive of COVID-19 on Chest X-ray or CT scan. Imaging will be continuing to be a crucial component in COVID-19 patient management.
Radiology and Imaging guideline for COVID-19
American College of Radiology (ACR) has clarify the appropriateness of Chest X-ray and CT scan for the screening, diagnosis and management of patients with suspected or known COVID-19 infections.
Findings on chest imaging in COVID-19 are not specific and overlap with other infections, including influenza, H1N1, Severely Acquired Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome(MERS). Being in the midst of the current flu season with a much higher prevalence of influenza, COVID-19, further limits the specificity of CT scan.
“ACR appropriateness criteria statement on Acute Respiratory Illness (2018)” states that Chest CT is ‘usually not appropriate’. A review from the “Cochrane database of systematic reviews on Chest radiographs for acute lower respiratory tract infections” concluded that Chest X-ray did not improve the clinical outcomes for patients with lower respiratory tract infections.
The presentation of the NCIP in intensive care unit patients indicated bilateral subsegmental areas of air-space consolidation, whereas in non-intensive care unit patients, transient areas of subsegmental consolidation are seen early with bilateral ground-glass opacities being predominantly later during the disease. No pleural effusion or cavitation has been reported so far in confirmed cases of NCIP, but pneumothorax was reported in 1% of patients (1 of 99) in a study by Chen et. al.
Radiologic features of coronavirus syndromes
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Infection Control and Use of Radiology Equipment’s for Covid-19
Primary health care and other medical providers should limit the visit of patients with suspected influenza or COVID-19 to healthcare facilities, to minimize the risk of spreading COVID-19 infection.
CDC has asked that patients and visitors to healthcare facilities be screened for symptoms of acute respiratory illness, be asked to wear a surgical mask and be evaluated in a private room with the door closed.
Environmental cleaning and decontamination of rooms occupied by a patient with suspected or known COVID-19 infection should be done by thorough cleaning of surfaces by someone wearing proper protective equipment with a low or intermediate level disinfectant, such as iodophor germicidal detergent solution, ethyl alcohol, or isopropyl alcohol.
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Air flow within fixed radiography or CT scanners rooms should be considered before imaging the next patient. Depending on the air exchange rates, room may need to be unavailable for approximately 1 hour after imaging infected patients.
CT scan should not be used to screen for or as a first line test to diagnose COVID-19.
CT scan should be used sparingly and reserved for hospitalized symptomatic patients with specific clinical indications for CT scan.
We can avoid bringing patients into radiography rooms by deploying satellite radiography and dedicated radiographic equipment’s (portable radiography units) in ambulatory care facilities for use when Chest X-rays are considered medically necessary.
Radiology professionals (Radiologist and Radiologic Technologist) should familiarize themselves with the CT scan appearance of COVID-19 infection in-order to be able to identify findings and imaging protocol consistent with infection in patients image for other reasons.
ACR strongly urges caution in taking CT scan of Chest to inform decisions on whether to test a patient for COVID-19.
A normal CT scan of Chest does not mean a person does not have COVID-19 infection and an abnormal CT scan is not specific for diagnosis.
A normal CT should not dissuade a patient from being quarantined when otherwise medically appropriate. Clearly, locally constrained resources may be a factor in such decision making.
Diagnostic imaging facilities should have guideline in place to manage individuals with known or suspected case of COVID-19. If properly prepared, radiology departments personnel can take greater measures to manage the impact of the COVID-19 outbreak on the department and staff.
Future Challenges for Radiography Professionals to fight against the COVID-19
Due to the global pandemic of COVID-19, World Health Organization has categorized Nepal as high-risk country for epidemic. Radiography professionals (Radiologic Technologist and Radiographers) are the first-line health care workers who might be exposed to novel COVID-19 while performing the imaging procedures like Chest X-ray and CT scan.
Radiography professional are part of chain of infection to overcome spread of COVID-19. Currently there is a huge shortage of essentials protective equipment (Mask, Hand sanitizer and PPE) in major central referral and provincial hospitals of Nepal. For the prevention and spread of COVID-19 we request Ministry of Health and Population, Government of Nepal to provide the essentials equipment (N95 mask, a disposable isolation gown with fluid-resistant characteristics, a pair of disposable gloves with coverage over gown cuffs, eye protection with goggles, and probably a face mask over googles) in every radiology departments of provincial and central hospital of Nepal for Radiographers, Radiologic Technologist and Radiologist. We request Nepal Radiologist Association and Nepal Radiological Society to make the standard guideline for performing the Chest X-ray and CT scan so that all the radiology professional could follow to minimize the infection control due to COVID-19.
We radiography professionals are determined to provide high level of patient care performing the imaging procedures during the COVID-19 outbreak. Together we can help stop and control the spread of COVID-19. Let’s together stop COVID-19. Stay safe and healthy.
Reference
1. ACR recommendations for the use of chest radiography and computed tomography (CT scan) for suspected COVID-19 infection (updated March 19, 2020)
2. Center for Disease Control
3. World Health Organization
4. Soheil Kooraki, Melina Hosseiny, Lee Myers, Ali Gholamrezanezhad. Coronavirus (COVID-19) Outbreak: What the department of Radiology Should know. Journal of Americal College of Radiology,2020.
5. Francis Deng, Daniel J.Bell, et al. Coronavirus disease 2019 (COVID-19). www.radiopedia.org
6. Handbook of COVID-19 prevention and treatment.
Author Suraj Sah is graduate of B.Sc. Medical Imaging Technology from National Academy of Medical Sciences, Bir Hospital and currently working as Radiologic Technologist (CT Scan) at Department of Radiology and Imaging, Chirayu National Hospital and Medical Institute Pvt. Ltd., Kathmandu, Nepal.
