The target sign has been described to be a result of perivascular inflammation and organizing pneumonia. Whether there is also an element of infarction is uncertain.
As seen in the video, the sign consists of the pin-point or sometimes thickened vessel in the center (red arrow), the perivascular opacity of inflammation (blue arrow), the relative “spared” halo (yellow arrow) and the ground glass halo (green arrow).
Irrespective of the exact reason for the target sign, its presence implies that there is a vasculopathy / angiopathy.
