by John R. Fischer
, Senior Reporter | January 25, 2022
Members of the SNMMI COVID-19 Task Force have observed a new imaging pattern on FDG PET/CT scans and say the Omicron variant may be the reason for it.
While patterns with previous strains of COVID-19 have primarily involved the lungs, the new findings are mainly centered in the upper aerodigestive tract and cervical lymph nodes, according to the Task Force.
Specifically, it saw prominent symmetric FDG uptake throughout the nasopharynx, oropharynx and tonsils with or without associated FDG-avid cervical lymphadenopathy, particularly in the suprahyoid neck, according to HospiMedica
“Based on what is known about the Omicron variant, the scientists believe that this pattern, whenever correlated with COVID-19 infection, is a result of the presently dominant Omicron strain,” said SNMMI in a statement.
The pattern has been seen in both adults and children.
The Task Force recommends that radiologists should keep an eye out for the pattern when interpreting FDG PET/CT interpretations, and consider the possibility of the Omicron variant in the differential diagnosis. The pattern, however, cannot be used to diagnose COVID-19 infection. The Task Force recommends that radiologists who see this pattern should:
- Check patient records for a recent positive COVID-19 test.
- Determine if a patient is at higher risk for COVID-19 based on their current symptoms or recent exposure or travel. If so, a recommendation for a COVID-19 test in an appropriate setting can be made.
- They should compare their findings with previous FDG PET/CT exams and the patient’s history to determine if this represents chronic inflammatory/reactive process or stable malignancy such as lymphoma.
Additionally, the association says that radiologists should consider various differential diagnostic possibilities if the pattern is new or if interval progression is seen. This includes, but is not limited to, infection with COVID-19; other viruses, such as Epstein-Barr virus; malignancy, and bacterial infections. While the pattern may also be seen in children and younger adults, it should be interpreted cautiously in view of normal increased activity that can be physiologic. Correlations should be drawn with history, and symptoms and comparisons to prior exams should be carried out.