Fig. 2. Measurement of the VTI. If the actual length of the VA is aV4L and its straight length is sV4L, then VTI is calculated as aV4L/sV4L. VA, vertebral artery; VTI, vertebral artery tortuosity index.
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.