A special report is now available to familiarize radiologists on how to identify signs of the coronavirus on CT scans

Special report highlights key findings for coronavirus on CT scans

February 06, 2020
by John R. Fischer, Senior Reporter
American and Chinese researchers have compiled a special report that details signs to look for on CT scans when examining patients suspected of carrying the Wuhan coronavirus.

They assert that radiologists must be familiar with key findings of the disease — officially known as 2019-nCoV — to detect, diagnose and recommend treatment early, and help stop the outbreak, which has affected thousands globally since first observed in December.

“This is a new disease that is being characterized for the first time, and there are only a handful of cases in the entire United States. At this point, no radiologist has wide exposure or experience with the radiology findings of 2019-nCoV,” Dr. Michael Chung, assistant professor in the department of diagnostic, interventional and molecular radiology in the Mount Sinai Health System in New York, and Dr. Adam Bernheim, a cardiothoracic radiologist at Mount Sinai and a colleague who worked on the report with Dr. Chung, told HCB News. “Coronavirus pneumonias share similar imaging characteristics, as we have seen similarities between this outbreak and other coronavirus infections such as SARS and MERS. The more radiologists are familiar with this disease category, the better they will be able to recognize any future coronavirus pneumonias.”

Originating within Wuhan City in the Hubei province of China, the disease has been nicknamed “Wuhan coronavirus” and “novel coronavirus”. It belongs to the same family of viruses as Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS). The World Health Organization first detected its presence in December when it was made aware of several cases of a respiratory illness clinically resembling viral pneumonia.

It declared it to be an epidemic this month, that to date that has affected at least 24,000 in China, as well as individuals in other countries. A twelfth case was recently confirmed in the U.S., with the first instance of person-to-person spread confirmed on January 30. The result has led countries to suspend flights to China, according to NBC News.

To help radiologists recognize and diagnose the disease in the early stages, researchers compiled a series of retrospective cases for 21 patients with the virus admitted to three hospitals in three provinces of China between January 18 and January 27. The 13 men and eight women each underwent chest CT scans, with laboratory testing of respiratory secretions after confirming each to be positive for infection.

The initial CT assessed each patient for the following:
• presence of ground-glass opacities
• presence of consolidation
• number of lobes affected by ground-glass or consolidative opacities
• degree of lobe involvement, in addition to overall lung “total severity score”
• presence of nodules
• presence of a pleural effusion
• presence of thoracic lymphadenopathy (lymph nodes of abnormal size or morphology)
• presence of underlying lung disease such as emphysema or fibrosis

The analysis found that the virus appears on CT scans with bilateral ground-glass and consolidative pulmonary opacities. Other findings that may be helpful for early diagnosis are nodular opacities, crazy-paving pattern, and a peripheral distribution of the disease. In addition, lung cavitation, discrete pulmonary nodules, pleural effusions and lymphadenopathy are characteristically absent in cases of 2019-nCoV.

Follow-up imaging in seven of eight patients showed increasing extent and density of airspace opacities, signifying mild or moderate progression of the disease. Chung and Bernheim warn, however, that CT alone is not enough to rule out the presence of the virus, as one of three patients who had a normal initial chest CT progressed three days later and developed a solitary nodular ground-glass lesion in the right lower lobe. They say this pattern may represent the very first radiologically visible manifestation of the disease in some patients.

A second patient, in contrast, had a normal follow-up chest CT four days after receiving a normal initial imaging exam. Such findings, they say, may be due to the infection being characterized by an incubation period of several days, and there may be a phase where the viral infection exhibits symptoms prior to visible abnormalities on CT.

“While CT imaging serves as a powerful screening tool, especially in the center of the epidemic, the gold standard for diagnosis is the laboratory tests that are performed by clinicians,” they said.

Further study is required to understand how patients fare after treatment. Experience and imaging findings from the MERS and SARS epidemics may help to address the current outbreak, say Chung and Bernheim.

Any other thoracic abnormalities found in each were also noted.

The findings were published in the journal, Radiology.