Experts say chest CT scans and X-rays can reveal COVID-19 infections that go undetected by RT-PCR, which is currently the chief method for determining if a person has the disease.

Speaking at a conference organized by the Korean Federation of Science and Technology Societies last week, radiologist Do Kyung-hyun of Asan Medical Center in Seoul said the chest radiographs of otherwise asymptomatic patients sometimes revealed signs of infiltration in their lungs.

“Such radiological abnormalities can lead to early detection of suspected pneumonia in patients,” she said.

Do said up to half of COVID-19 patients show normal CT scans in the first two days after the onset of flu-like symptoms. Image findings in early stage of the disease are marked by patterns known as “ground glass opacity” or a partial filling of air spaces in the lungs, she said.

“These radiological findings will play a vital role in diagnosing COVID-19 pneumonia and assessing the prognosis,” she said.

During a Feb. 26 press briefing held at the National Medical Center, Seoul National University Hospital’s infectious disease specialist Oh Myoung-don said some patients with COVID-19 pneumonia “did not necessarily experience severe symptoms.”

“This is very much unlike patients of other types of pneumonia that I’ve seen in my 30-plus years of practicing medicine,” he said.

Oh, who also heads the NMC’s clinical committee for emerging infectious diseases, added that COVID-19 was capable of killing young and healthy individuals, albeit rarely.

“There have been reports of COVID-19 pneumonia patients without obvious symptoms whose tests came out normal -- but when you look at their chest imaging, it would show indications of infections,” said pulmonologist Chun Eun-mi of the Ewha University Medical Center.

On a more hopeful note, she said there were also cases where symptoms improved without intervention.

But relying solely on X-ray or CT scans for COVID-19 diagnosis is risky and ill-advised, according to Sung Heung-sup, a laboratory medicine specialist at Asan Medical Center.

“There are other diseases associated with the patterns of hazy patches known as ground glass opacity. Having these signs alone cannot mean the patient is infected with the pathogen,” he said.

By Kim Arin (arin@heraldcorp.com)