An official website of the United States government
The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before
sharing sensitive information, make sure you’re on a federal
government site.
The site is secure.
The https:// ensures that you are connecting to the
official website and that any information you provide is encrypted
and transmitted securely.
Feinstein KA, Fernbach SK.Feinstein KA, et al.AJR Am J Roentgenol. 1987 Nov;149(5):997-1000. doi: 10.2214/ajr.149.5.997.AJR Am J Roentgenol. 1987.PMID: 3314433