Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Comparison between the halo sign and hyperechoic wall thickening. Halo sign is characterized by homogeneous, circumferential hypoechoic wall thickening visualized in longitudinal (a) and transverse (b) views. Hyperechoic wall thickeningis defined by circumferential wall thickening visualized in longitudinal (c) and transverse (d) views, hyperechogenicity compared with adjacent arterial segments within the same artery, and absence of arteriosclerosis.
