What We Can Learn About Coronavirus from Images of SARS and MERS?

A paper recently published in the American Journal of Roentgenology has found that scans of patients with COVID-19 share many similarities with imaging studies of severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS).

According to the World Health Organization (WHO), the pandemic has so far (as of the date of this article) resulted in over 191,000 cases and more than 7,800 deaths. Although most of those infected only have cold-like symptoms, about 16 percent are serious cases where patients suffer from pneumonia and breathing difficulties.

Coronaviruses are responsible for both the 2003 SARS pandemic in Guangdong Province, China and MERS, which was first diagnosed in 2012 in Saudi Arabia. Both viruses cause rapid-developing pneumonia and have many similar imaging features. The study authors note that radiographs of MERS and SARS patients are abnormal for around 80 percent of patients. They also found that for both viruses, peripheral multifocal airspace opacities on radiography and CT were commonly noted. Yet, there are a number of differences between the two viruses: SARS typically demonstrates unilateral disease with peripheral distribution, whereas MERS showed bilateral confluent diffuse airspace opacities, akin to symptoms of acute respiratory syndrome.

When it comes to COVID-19, radiology researchers are seeing overlapping signs with previous coronaviruses. These similarities include patchy or diffuse asymmetric airspace opacities, and abnormal CT scans in 86 percent of patients with the vast majority presenting bilateral lung involvement. The researchers point out that despite these commonalities, “involvement of both lungs on initial imaging is more likely to be seen with COVID-19; initial chest imaging abnormalities in SARS and MERS are more frequently unilateral.”

The researchers urge physicians to order follow-up CT scans for patients in recovery from COVID-19 to keep an eye on long-term or permanent pulmonary damage and fibrosis, a condition that many SARS and MERS patients developed.