From ground-glass opacities to pulmonary emboli. A snapshot of the evolving role of a radiology unit facing the COVID-19 outbreak.

Sir—The aim of this letter is to report what is currently happening in our Radiology Department at a tertiary infectious disease hospital in Milan, a hotspot for COVID-19, 2 months after the outbreak of the epidemic.

The early phase was highly critical, and we had to find ways to manage both suspected and confirmed cases, which involved separating them from patients undergoing imaging tests for other reasons such as oncological staging or follow-up. At the time, promptness of action was favoured amongst clinicians, and in agreement with the most recent consensus statements , , computed tomography (CT) was not used as a screening test, but reserved for selected symptomatic patients. As a result, most suspected or confirmed COVID-19 patients were examined using chest radiography, thus minimising patient radiation exposure and infection transmission to the radiology staff and uninfected patients.

In the course of time, about a month after the epidemic outbreak, we noticed a sudden rise in requests for CT, mostly related to CT angiography (CTA) studies to exclude acute pulmonary embolism (PE). Based on our experience of 30 consecutive CTA examinations performed in confirmed COVID-19 patients, the prevalence of PE is approximately 35%, with peripheral branch preponderance. Preliminary data indicate that approximately 5–10% of COVID-19 patients who require mechanical ventilation suffer from acute PE or deep venous thromboembolism (DVT). The probability is higher in those with signs of DVT, inexplicable hypotension or tachycardia, worsening respiratory status, or risk factors for thrombosis. The rate of micro-PE is probably even higher, as suggested by unreleased autopsy results.

As undiagnosed or untreated PE may negatively affect patient outcome, empirical therapeutic anticoagulation has been recommended; however, considering the lack of evidence regarding improvement and the risk of major bleeding, CTA should be used to confirm this diagnosis and to support any decision to start therapeutic anticoagulation.

Another clinical scenario that is progressively causing an increase in CT requests is pulmonary fibrosis. In fact, COVID-19 patients, particularly those recovering from a period in the intensive care unit, are at risk of developing fibrosis.

In conclusion, after having faced preparedness and diagnostic procedures, radiology departments should also be prepared to deal with these two clinical issues.

Conflict of interest

The authors declare no conflict of interest.