## Abstract We show that the EPI time course in functional MR imaging at 4 Tesla displays a multiphasic response in response to photic stimulation. Focal areas of gray matter display an initial negative change in signal intensity that reaches a maximum of 1 % about 2 s after the onset of photic sti
Fast interleaved echo-planar imaging with navigator: High resolution anatomic and functional images at 4 tesla
✍ Scribed by Seong-Gi Kim; Xiaoping Hu; Gregor Adriany; Kâmil Uǧurbil
- Publisher
- John Wiley and Sons
- Year
- 1996
- Tongue
- English
- Weight
- 872 KB
- Volume
- 35
- Category
- Article
- ISSN
- 0740-3194
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
Echo‐planar Imaging (EPI) Is sensitive to magnetic field inhomogeneities, which lead to signal loss and geometric distortions of the image. Magnetic field inhomogeneities induced by susceptibility differences, as encountered in the human body, increase with the magnetic field strength, thus, complicating implementation of high resolution EPI techniques on high magnetic field systems. These problems were overcome by using a fast multishot high resolution EPI method that uses variable flip angles, center‐out k‐space sampling, and navigator echoes. This approach maximizes signal‐to‐noise ratio, reduces flow artifacts, and permits correction of intersegment amplitude and phase variations, providing high spatial and temporal resolution. This scheme can be implemented with a single magnetization preparation for contrast that precedes the segments. The utility of this ultrafast segmented EPI technique with navigator is demonstrated for anatomic and functional imaging studies on the human brain at 4 T.
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