Chest CT Reveals Long-Term Abnormalities in COVID-19 Patients

Chest CT scans show thickening of lung tissue after six months in more than 70 percent of patients who are COVID-19-positive.

In a new study published July 27 in Radiology, a team of investigators from Italy shared that it is possible to predict which patients are at higher risk for long-term effects by combining a baseline chest CT scan with clinical data.

Although chest CT findings have been used extensively during the pandemic, providers have mainly relied on them to reveal short- and mid-term progression of disease. As the pandemic enters this new phase, there is a need for a more long-term assessment.

“At six-month follow-up 72 percent of patients showed late sequelae, in particular fibrotic-like changes,” said the team led by Damiano Caruso, M.D., Ph.D., medical director with Sapienza University in Rome. “Baseline [lung severity score] and [quantitative chest CT] of well-aerated lung showed an excellent performance in predicting fibrotic-like changes at six-month chest CT.”

In order to learn more about any long-term impacts of the virus, Caruso’s team examined baseline CT scans captured between March 2020 and May 2020 from 118 patients who had moderate-to-severe COVID-19 infection. They followed up with additional CT scans after six months, looking at lung severity scores, quantitative chest CT measures, and qualitative findings.

In addition, the team evaluated three strategies that could predict long-term effects – radiological data alone, clinical data alone, or a combination of the two.

Based on their evaluation, the team determined that 72 percent of patients had fibrotic-like changes in their lungs, and 42 percent exhibited ground glass opacities. Their results indicated that quantitative chest CT measures and lung severity scores could effectively predict these fibrotic-like changes at follow-up.

However, there is a lack of consensus on whether Caruso’s team is taking the best approach in evaluating these lung changes in patients who have had COVID-19. In an accompanying editorial, Athol Wells, consultant chest physician at Royal Brompton Hospital, and Anand Devaraj, professor of practice in thoracic radiologist at the National Lung and Heart Institute and consultant thoracic radiologist at the Royal Brompton Hospital, pointed out that all patients with residual disease at six months had a positive fibrotic-like score.

“The apparent increase in the prevalence of ‘fibrotic-like’ change at six months is highly deceptive as baseline scans were performed at admission, now when the disease was most severe, and before periods of prolonged ventilation in some of the study participants,” they said. “A more progressive lung fibrosis hypothesis post-COVID would instead require evaluating change from baseline CT performed at discharge from intensive care or at hospital discharge.”

Overall, they said, there is an urgent need to assess the clinical significance of residual disease on CT, as well as to create predictive models against this end point in future work.

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