New-Baseline Chest Imaging in Discharged COVID-19 Patients Could Help Identify Those at Highest Risk of Reinfection

“New-baseline” imaging obtained from COVID-19 patients at the time of hospital discharge or clinical recovery may help clinicians to identify those at the highest risk of a relapse or reinfection from the SARS-CoV-2 virus or a secondary viral infection such as influenza.

Researchers from Keck School of Medicine of the University of Southern California (Los Angeles, CA, USA) have suggested that “new-baseline” imaging can be used to determine if readmissions are from relapse or reinfection of COVID-19, resolving COVID-19 or potentially a different viral infection (influenza), but also for long term sequela of COVID-19 lung infection.


COVID-19 relapse or reinfection may lead to readmission, which may cause a diagnostic challenge between recently infected patients and reinfections. Compounding this problem is the post-viral lung sequela that may be expected after COVID-19 pneumonia, similar to both Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS). Although chest imaging may play a role in the diagnosis of primary SARS-CoV-2 infection, reinfection or relapse of COVID-19 will have similar imaging findings. According to the researchers, strategic use of imaging before discharge may be helpful in the subset of the population at the highest risk of a secondary viral infection such as influenza. Determining the residual abnormalities in post-discharge imaging can guide clinicians in the long-term management of patients for many years to come.

Pulmonary imaging abnormalities are highly likely to persistent in recovered COVID-19 patients. Early studies indicate that post-discharge/recovery radiologic imaging still reveals some abnormalities in recovered patients. The likelihood of residual pulmonary lesions after COVID-19 recovery will create additional challenges for imaging diagnosis between resolving pulmonary infection, reinfection with COVID-19 or a different virus (influenza). The use of a “new-baseline” imaging (preferably using CXR due to lower radiation) for high-risk patients can offer a snapshot of pulmonary findings either at the time of discharge or a follow-up examination. This could be especially important during the flu season, since influenza could cause similar clinical and radiological abnormalities as COVID-19.

Hence, the potential added value of a new-baseline chest radiography in patients who are recovered from SARS-CoV-2 infection cannot be overemphasized. The method of utilizing this new reference will assist the clinicians in facing possible future challenges. This may predict long-term pulmonary function, but also new-baseline chest imaging can guide clinicians in a better decision when encountering lung abnormalities on follow-up imaging of patients who once had COVID-19. Therefore, the researchers have recommended chest imaging at the time of discharge or shortly thereafter in patients at the highest risk of secondary viral infection and/or have comorbidities. This baseline imaging might also be of great value for continued surveillance of post-discharge COVID-19 patients. Determining the residual abnormalities in post-recovery imaging (specifically using CXRs as the main imaging tools due to its lower radiation, unless CT scans had been performed for other reasons) will guide clinicians in the long-term management of these patients for many years to come.

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Keck School of Medicine