Author: Mr. Suraj Sah is a post-graduate student of Medical Imaging Technology at Department of Radiology and Imaging, National Academy of Medical Sciences, Bir Hospital, Kathmandu, Nepal.
MoHP) the second wave of Corona virus infectious disease-2019 is multiplying very terrifically. The press release of MoHP on 6th May 2021 states that out of 21142 Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) and Antigen test, 9070 (8970 RT-PCR & 100 Antigen) has been diagnosed positive in a single day with 54 deaths. MoHP has warned that the situation may go beyond control and management due to the lack of sufficient amount of health workforce and hospital infrastructure (ICU, Oxygen power plant, Ventilator, personal protective equipment, imaging equipment). Most of the non-governmental hospitals inside the Kathmandu valley have already released notice regarding the overflow of the COVID-19 positive patients at their premises.ccording to the Government of Nepal, Ministry of Health and Population (
Kathmandu valley being the highly densely populated area, most of the COVID-19 patients is here. Government of Nepal has declared strict restrictions (lockdown) up to end of Baishakh, 2078. And has advised all the asymptomatic (mild case) COVID-19 patients to remain self-isolated at their home. Due to the lack of knowledge, improper guideline and recommendations in public, people are in visiting hospitals and making calls to perform chest imaging once they are RT-PCR/Antigen positive though they are asymptomatic with mild cases.
World Health Organization (WHO) has published following guidelines and recommendations regarding chest imaging for treatment and management of COVID-19 disease. If available, RT-PCR and Antigen is the first test which should be done to diagnose COVID-19. Chest imaging includes the Chest X-ray, Chest CT scan and Lung Ultrasound as the diagnostic workup for monitoring disease progression or disease recovery.
WHO recommends that the choice of imaging modality should be made through shared decision in-between referring physician, the radiologist, and the patient whenever possible? One should keep in mind the availability of imaging equipment at their own hospital premises. Furthermore, Patient should be informed about the imaging procedures and its advantages.
Compared to Chest CT scan, chest radiographs have lower sensitivity and might have higher specificity. Chest x-ray is easily available in every hospital and have lower radiation dose and can be performed at bedside with portable imaging equipment which minimizes the risk of cross-infection among the radiology staff and other people during the patient transport. If possible, a unit and radiography professionals (Radiographers and Radiologic Technologist) dedicated to patients with COVID-19 should be considered to prevent the exposure of all the radiography staffs. Radiography professionals should always focus to minimize the radiation dose, while maintaining the diagnostic image quality with the use of digital imaging rather than film-screen equipment. But this seems impractical because of infrastructures, availability of equipment and the infection has gone to local level where all patients are termed as COVID patient.
Chest CT scan has highest sensitivity, but lower specificity as compared to chest radiography. Chest CT scan (5-8 mSv) delivers higher radiation dose as compared to the chest radiograph (0.02 mSv) and most importantly is only useful in patients with some preexisting pulmonary diseases. CT Pulmonary Angiography also plays pivotal role in diagnosis of pulmonary arterial thrombosis or thromboembolism. Chest CT scan should only be advised in moderate to severe COVID-19 patients if he/she has respiratory distress and worsen existing condition due to lower oxygen saturation. Also, Radiography professionals must consider the potential harm of ionizing radiation from CT scan especially in case of pregnant women and pediatric population. A low dose CT protocol is advised for the screening purpose. As not all the hospital has the facility of CT, this seems challenge to most of the centers.
Lung ultrasound has exceptionally low certainty evidence supporting its diagnostic accuracy but might be helpful as an alternative modality in case of pregnant patients, children and in patient with mechanical ventilation for the diagnosis of pleural effusion and heart conditions. It can be performed bedside, but it requires the proximity of the US operator with the patient for longer duration which needs specific infection prevention and control precautions.
Radiology professionals should ensure proper use of personal protective equipment and disinfection of imaging equipment’s. Nowadays, the Radiology and Imaging Department are flooded with unnecessary and self-referral chest imaging procedures of COVID-19 positive patients, due to lack of standard government guidelines. There is also huge lack of collaboration between the referring physician and radiologist concerning imaging procedures, which has increased the unnecessary workload for the radiography professionals. The local protocols are essential and should be developed for the appropriate use of imaging equipment by the national regulatory body, Nepal Medical Council (Radiologist), Nepal Health Professional Council (Radiographer and Radiologic Technologist) and Nepal Health Research Council (NHRC, MoHP) in-collaboration with Nepal Radiologist Association (NRA) and Nepal Radiological Society (NRS). These protocols will help to restrict the haphazard use of imaging procedures (x-ray and CT scan) and will minimize the patient’s financial burden and radiation dose. Moreover, justified imaging procedures will limit the Radiographers and Technologist in direct exposure with COVID-19 patients and work burden to the imaging operators.
The national regulatory body (NMC, NHPC and NHRC, MoHP) and national non-governmental organization (NRA and NRS) should provide appropriate training to Radiologists and Radiologic Technologist on infection, prevention and control practices and ensure sufficient management of typical findings of COVID-19 through accepted local protocols. Ministry of Health and Population must develop and circulate the policy and pathway for imaging, related to COVID-19 via flow charts or diagrams to every health institution where imaging equipment’s are available. In addition, Government should develop Teleradiology facility in every government hospital that will help transforming the images for remote reporting where there is unavailability of onsite Radiologist.
Use of Chest Imaging in the Diagnosis and Management of COVID-19: A WHO Rapid Advice Guide, https://doi.org/10.1148/radiol.2020203173