But coronavirus scans tend to have white patches that radiologists refer to as "ground glass opacity."
An analysis of nearly 140 coronavirus scans said patches of ground glass on both lungs were a hallmark of the virus.
Many patients tended to worsen quickly. Their ground-glass patches became more pronounced after a few days.
Scans from a 27-year-old woman who worked in Wuhan showed a "ground-glass halo" — white patches that surround a small nodule.
Some patients also exhibited a "crazy-paving pattern," which refers to little lines inside the ground-glass patches.
A Shanghai study also identified a mesh-like pattern called "reticulation," which is visible in this scan of a 75-year-old man.
The Shanghai researchers ultimately determined that three components are needed to diagnose a coronavirus patient: fever and/or cough, ground-glass patches in both lungs, and a history of exposure to individuals from Wuhan.