Advanced investigations on rapid steady-state MR imaging and its clinical applications (1/3)
Date Issued
2005-07-31
Date
2005-07-31
Author(s)
DOI
932213E002135
Abstract
The specific aim for the first fiscal year
of this project is to investigate the effects of
flip angle setting in 3D balanced steady-state
free precession (SSFP) imaging on the image
contrast between cerebrospinal fluid (CSF)
and its surrounding cerebral parenchyma, at
the same time to examine the presence and
extent of aliasing artifacts along the slice
selection direction. Theoretical derivations
of the signal behavior in the steady state
regime indicated that the extent of slice
aliasing artifacts decreased as the flip angle
was lowered, at the expense of a sacrifice in
CSF-parenchyma contrast. Experimental
data from six healthy subjects and four
patients showed that prominent slice aliasing
artifacts were found to affect nearly 30% of
the imaging slices when using the commonly
employed 700 flip angle. The extent of slice
aliasing artifacts and CSF-parenchyma
contrast agreed well with theoretical
predictions. In particular, a designated flip
angle of 400 showed nearly 60% reduction in
the extent of slice aliasing with only 20%
decrease in CSF-parenchyma contrast, as
compared with the use of 700 flip angle. A
flip angle of about 400 is thus recommended
for 3D balanced SSFP MR ventriculocisternography
with sufficient CSFparenchyma
contrast at a clinically acceptable
level of slice aliasing artifacts.
Subjects
磁振造影
腦室腦池影像
腦脊
髓液
髓液
穩定態自由旋進
切面方向外來假
影
影
Publisher
臺北市：國立臺灣大學電機工程學系暨研究所
Type
report
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