T1ρ MRI contrast in the human brain: Modulation of the longitudinal rotating frame relaxation shutter-speed during an adiabatic RF pulse

2006 ◽  
Vol 181 (1) ◽  
pp. 135-147 ◽  
Author(s):  
Shalom Michaeli ◽  
Dennis J. Sorce ◽  
Charles S. Springer ◽  
Kamil Ugurbil ◽  
Michael Garwood
Keyword(s):  
Human Brain ◽  
Rotating Frame ◽  
Mri Contrast ◽  
Rotating Frame Relaxation ◽  
Rf Pulse ◽  
Shutter Speed

scholarly journals Quantitative Assessment of Water Pools by T1p and T2p MRI in Acute Cerebral Ischemia of the Rat

2008 ◽  
Vol 29 (1) ◽  
pp. 206-216 ◽  
Author(s):  
Kimmo T Jokivarsi ◽  
Juha-Pekka Niskanen ◽  
Shalom Michaeli ◽  
Heidi I Gröhn ◽  
Michael Garwood ◽  
...  
Keyword(s):  
Correlation Time ◽  
Continuous Wave ◽  
Vasogenic Edema ◽  
Free Water ◽  
Rotating Frame ◽  
Mri Contrast ◽  
Water Fraction ◽  
Acute Cerebral Ischemia ◽  
Rotating Frame Relaxation

The rotating frame longitudinal relaxation magnetic resonance imaging (MRI) contrast, T1ρ, obtained with on-resonance continuous wave (CW) spin-lock field is a sensitive indicator of tissue changes associated with hyperacute stroke. Here, the rotating frame relaxation concept was extended by acquiring both T1ρ and transverse rotating frame ( T2ρ) MRI data using both CW and adiabatic hyperbolic secant (HSn; n = 1, 4, or 8) pulses in a rat stroke model of middle cerebral artery occlusion. The results show differences in the sensitivity of spinlock T1ρ and T2ρ MRI to detect hyperacute ischemia. The most sensitive techniques were CW- T1ρ and T1ρ using HS4 or HS8 pulses. Fitting a two-pool exchange model to the T1ρ and T2ρ MRI data acquired from the infarcting brain indicated time-dependent increase in free water fraction, decrease in the correlation time of water fraction associated with macromolecules, and increase in the exchange correlation time. These findings are consistent with known pathology in acute stroke, including vasogenic edema, destructive processes, and tissue acidification. Our results show that the sensitivity of the spinlock MRI contrast in vivo can be modified using different spinlock preparation blocks, and that physicochemical models of the rotating frame relaxation may provide insight into progression of ischemia in vivo.

scholarly journals Parallel excitation in the human brain at 9.4 T counteractingk-space errors with RF pulse design

2010 ◽  
Vol 63 (2) ◽  
pp. 524-529 ◽  
Author(s):  
Xiaoping Wu ◽  
J. Thomas Vaughan ◽  
Kâmil Uğurbil ◽  
Pierre-François Van de Moortele
Keyword(s):  
Human Brain ◽  
Pulse Design ◽  
Parallel Excitation ◽  
Rf Pulse

Chemical exchange saturation transfer MRI contrast in the human brain at 9.4 T

NeuroImage ◽  
2018 ◽  
Vol 179 ◽  
pp. 144-155 ◽  
Author(s):  
Moritz Zaiss ◽  
Mark Schuppert ◽  
Anagha Deshmane ◽  
Kai Herz ◽  
Philipp Ehses ◽  
...  
Keyword(s):  
Human Brain ◽  
Chemical Exchange ◽  
Chemical Exchange Saturation Transfer ◽  
Saturation Transfer ◽  
Mri Contrast

scholarly journals Balanced spin‐lock preparation for B 1 ‐insensitive and B 0 ‐insensitive quantification of the rotating frame relaxation time T 1ρ

2020 ◽  
Author(s):  
Maximilian Gram ◽  
Michael Seethaler ◽  
Daniel Gensler ◽  
Johannes Oberberger ◽  
Peter M. Jakob ◽  
...  
Keyword(s):  
Relaxation Time ◽  
Rotating Frame ◽  
Spin Lock ◽  
Rotating Frame Relaxation

Measurement of Longitudinal and Rotating Frame Relaxation Times through Fully J-Decoupled Homonuclear Spectra

1999 ◽  
Vol 140 (1) ◽  
pp. 250-258 ◽  
Author(s):  
F. Guenneau ◽  
P. Mutzenhardt ◽  
D. Grandclaude ◽  
D. Canet
Keyword(s):  
Relaxation Times ◽  
Rotating Frame ◽  
Rotating Frame Relaxation

scholarly journals Frequency offset dependence of adiabatic rotating frame relaxation rate constants: relevance to MRS investigations of metabolite dynamics in vivo

2011 ◽  
Vol 24 (7) ◽  
pp. 807-814 ◽  
Author(s):  
Silvia Mangia ◽  
Timo Liimatainen ◽  
Michael Garwood ◽  
Ivan Tkac ◽  
Pierre-Gilles Henry ◽  
...  
Keyword(s):  
Relaxation Rate ◽  
Rate Constants ◽  
Frequency Offset ◽  
Rotating Frame ◽  
Rotating Frame Relaxation
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