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From virus behavior, to patient impact, to imaging implementation – what we know so far.
COVID-19 has been the worst attack on global health since the Spanish flu of 1918, according to Marie-Pierre Revel, doctor of medicine, during her opening lecture at the European College of Radiology 2020 virtual annual meeting. But, experience has led to several lessons learned.
“The pandemic has profoundly affected our lives, isolating us from each other and blocking all social and economic activity,” said Revel, professor of radiology and head of cardiothoracic imaging at Hôpital Cochin in Paris, during her plenary session. “We’ve experienced tragic events. People have died alone, and doctors have had to make difficult choices with limited resources.”
To date, she added, the global healthcare system has not yet been able to assess and evaluate the widespread impacts of the pandemic, but she was able to offer some guidance on how imaging services can best be used during the outbreak.
When and How to Use Chest CT
Although Revel echoed professional guidance and did not recommend using chest CT as a screening tool, there were instances where she said making use of the modality is beneficial.
For areas experiencing a large influx of patients, chest CT can help emergency departments save time in triaging patients and identifying those who might need hospitalization and greater patient management.
The scan can also play a role with patients who are facing surgery, she said, although the decision to use chest CT in these situations will likely be individualized by hospital. Still, she recommended considering conducting a scan before any head, neck, or thoracic surgery.
“For any surgery where there’s a risk of thoracic complications at the really active phase of the virus in a location,” she said, “it would be wise to do a CT scan to depict any silent expression of the disease.”
There are also some instances where providers should consider using contrast with the chest CT scan, she said. There is no recommendation for using contrast at the initial screening for COVID-19 infection, but introducing it for subsequent scans with patients who have worsening symptoms can offer a better picture into the patient’s condition. Using it would improve the provider's ability to see not only COVID-19 pneumonia, but also any existing pneumothorax or thrombolytic complications.
The Role for X-ray and Ultrasound
Alongside chest CT, there is a role for X-ray and ultrasound with COVID-19 patients, she said, but the parts they play are not as robust. For example, X-ray, she added, should only be used in patients with the most severe cases who cannot be transported to the CT suite. Still, when using this modality, be aware that it has drawbacks.
“The use of X-ray should only be with the most severe cases because we all know that X-ray is misleading in these situations,” she advised. “The patient is supine, making it difficult to depict pneumothorax or other complications.”
Ultrasound should be limited to pinpointing existing pneumothorax in patients who have mechanical ventilation, she said.
As a patient begins to recover from the viral infection, it can be difficult to know when to re-assess his or her progress, she said. Existing knowledge indicates that lesions begin to improve with the first three months post-infection, so she recommended this schedule for re-evaluating patients: one month, three months, six months, and one year.
As providers continue to render services, she said, there are certain things about the virus and its impacts, thus far, that should be remembered.
Virus details: It is known that the virus, which is transmitted by respiratory droplets, is drawn to angiotensin-converting enzyme 2 (ACE2) that is found on the surfaces of airways, alveolar and epithelial cells, and endothelial cells. It is also expressed in the kidneys, brain, intestines, and testes. However, ACE2 is less expressed in children, potentially playing a role in their lower risk of developing a viral infection, she said.
Virus behavior: It can take roughly five days between exposure and the appearance of symptoms, Revel said. And, there are several factors that can put a patient at greater risk, including older age, male gender, and pre-existing conditions, such as obesity, diabetes, and high blood pressure. It can also prompt a cytokine storm in some patients, as well as augment the pulmonary embolism risk, she added, and it has also been seen to prompt microvascular injury syndrome in the lungs and skin.
What Remains to Be Determined
There is still a lot left to learn about this virus and how it will impact patients and global public health, Revel said. As providers continue to manage cases, more attention should be paid to several factors confounding questions that could alter how the healthcare industry ultimately approaches the virus.
Overall, she said, providers should pursue answers to these questions:
Overall, she stressed, addressing these queries is critical.
“These questions need to be answered since the current COVID-19 pandemic might not be over,” she said, “or might not be the last.”
Read more of Diagnostic Imaging's ECR2020 coverage here.