Macroscopic static field inhomogeneity in the human brain during MRI examination

Haiying Liu; Edward Michel; Sean O. Casey; Walter A. Hall; Charles L. Truwit

doi:10.1117/12.465582

3 May 2002 Macroscopic static field inhomogeneity in the human brain during MRI examination

Haiying Liu, Edward Michel, Sean O. Casey, Walter A. Hall, Charles L. Truwit

Proceedings Volume 4682, Medical Imaging 2002: Physics of Medical Imaging; (2002) https://doi.org/10.1117/12.465582
Event: Medical Imaging 2002, 2002, San Diego, California, United States

Abstract

The macroscopic static field inhomogeneity is not only the source of MR signal loss in gradient echo based imaging techniques, but also the source of geometrical image distortion as well as a limitation of spectral resolution. This piece of information is useful for both active shimming coil design and clinical imaging application. In order to further understand the spatial variation of the macroscopic background static field in human brain during MRI examination, this static field inhomogeneity was measured from the adult human volunteers with a volumetric imaging scheme, which was based on a 3D gradient echo technique with two consecutive gradient echoes. All the human volunteers were scanned in supine position using a birdcage headcoil on a 1.5 T clinical whole body scanner. We have constructed a high resolution 3D static field map over the brain volume. All experimental results have shown consistently that there are mainly two spots in the brain tissue volume exhibiting relatively severe static magnetic field inhomogeneity . They are normally located in the brain areas in the inferior frontal lobe immediately anterior to the nasal cavity and in the inferior temporal lobe above the ear canals, where air spaces exist in the vicinity. At those locations, the observed offset frequency in the proton resonance reached about 50 Hz over 5 mm distance along the z direction at 1.5 Tesla, corresponding to 1.5 ppm/cm locally.

Citation Download Citation

Haiying Liu, Edward Michel, Sean O. Casey, Walter A. Hall, and Charles L. Truwit "Macroscopic static field inhomogeneity in the human brain during MRI examination", Proc. SPIE 4682, Medical Imaging 2002: Physics of Medical Imaging, (3 May 2002); https://doi.org/10.1117/12.465582

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available