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Identification of signal bias in the variable flip angle method by linear display of the algebraic Ernst equation

Helms, Gunther LU ; Dathe, Henning; Weiskopf, Nikolaus and Dechent, Peter (2011) In Magnetic Resonance in Medicine 66(3). p.669-677
Abstract
A novel linear parameterization for the variable flip angle

method for longitudinal relaxation time T1 quantification from

spoiled steady state MRI is derived from the half angle tangent

transform, t, of the flip angle. Plotting the signal S at coordinates

x=St and y=S/t, respectively, establishes a line that

renders signal amplitude and relaxation term separately as y-intercept

and slope. This representation allows for estimation of

the respective parameter from the experimental data. A comprehensive

analysis of noise propagation is performed. Numerical

results for efficient optimization of longitudinal relaxation

time and proton density mapping... (More)
A novel linear parameterization for the variable flip angle

method for longitudinal relaxation time T1 quantification from

spoiled steady state MRI is derived from the half angle tangent

transform, t, of the flip angle. Plotting the signal S at coordinates

x=St and y=S/t, respectively, establishes a line that

renders signal amplitude and relaxation term separately as y-intercept

and slope. This representation allows for estimation of

the respective parameter from the experimental data. A comprehensive

analysis of noise propagation is performed. Numerical

results for efficient optimization of longitudinal relaxation

time and proton density mapping experiments are derived.

Appropriate scaling allows for a linear presentation of data that

are acquired at different short pulse repetition times, TR << T1

thus increasing flexibility in the data acquisition by removing the

limitation of a single pulse repetition time. Signal bias, like due

to slice-selective excitation or imperfect spoiling, can be readily

identified by systematic deviations from the linear plot. The

method is illustrated and validated by 3T experiments on phantoms

and human brain. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Magnetic Resonance in Medicine
volume
66
issue
3
pages
669 - 677
publisher
Wiley Online Library
external identifiers
  • scopus:80051689849
ISSN
1522-2594
DOI
10.1002/mrm.22849
language
English
LU publication?
yes
id
56fade86-e675-4829-bd83-04464f4e0061 (old id 8773491)
alternative location
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3193384/
date added to LUP
2016-02-27 00:53:47
date last changed
2017-04-23 03:16:48
@article{56fade86-e675-4829-bd83-04464f4e0061,
  abstract     = {A novel linear parameterization for the variable flip angle<br/><br>
method for longitudinal relaxation time T1 quantification from<br/><br>
spoiled steady state MRI is derived from the half angle tangent<br/><br>
transform, t, of the flip angle. Plotting the signal S at coordinates<br/><br>
x=St and y=S/t, respectively, establishes a line that<br/><br>
renders signal amplitude and relaxation term separately as y-intercept<br/><br>
and slope. This representation allows for estimation of<br/><br>
the respective parameter from the experimental data. A comprehensive<br/><br>
analysis of noise propagation is performed. Numerical<br/><br>
results for efficient optimization of longitudinal relaxation<br/><br>
time and proton density mapping experiments are derived.<br/><br>
Appropriate scaling allows for a linear presentation of data that<br/><br>
are acquired at different short pulse repetition times, TR &lt;&lt; T1<br/><br>
thus increasing flexibility in the data acquisition by removing the<br/><br>
limitation of a single pulse repetition time. Signal bias, like due<br/><br>
to slice-selective excitation or imperfect spoiling, can be readily<br/><br>
identified by systematic deviations from the linear plot. The<br/><br>
method is illustrated and validated by 3T experiments on phantoms<br/><br>
and human brain.},
  author       = {Helms, Gunther and Dathe, Henning and Weiskopf, Nikolaus and Dechent, Peter},
  issn         = {1522-2594},
  language     = {eng},
  number       = {3},
  pages        = {669--677},
  publisher    = {Wiley Online Library},
  series       = {Magnetic Resonance in Medicine},
  title        = {Identification of signal bias in the variable flip angle method by linear display of the algebraic Ernst equation},
  url          = {http://dx.doi.org/10.1002/mrm.22849},
  volume       = {66},
  year         = {2011},
}