longitudinal relaxation


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lon·gi·tu·di·nal re·lax·a·tion

in nuclear magnetic resonance, the return of the magnetic dipoles of the hydrogen nuclei (magnetization vector) to equilibrium parallel to the magnetic field, after they have been flipped 90°; varies in rate in different tissues, taking up to 15 s for water. See: TI.
Farlex Partner Medical Dictionary © Farlex 2012

longitudinal relaxation

An MRI term for the return of longitudinal magnetisation to equilibrium after excitation due to an exchange of energy between the nuclear spins and the lattice.
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.

lon·gi·tu·di·nal re·lax·a·tion

(long'ji-tū'di-năl rē'lak-sā'shŭn)
magnetic resonance imaging The return of the magnetic dipoles of the hydrogen nuclei (magnetization vector) to equilibrium parallel to the magnetic field, after they have been flipped 90°; varies in rate in different tissues, taking up to 15 seconds for water.
See: TI
Medical Dictionary for the Health Professions and Nursing © Farlex 2012
References in periodicals archive ?
The initial longitudinal relaxation length [[sigma].sub.x0] can be calculated according to Equation 14 from the relation of the longitudinal slip stiffness [K.sub.[lambda]] and the longitudinal stiffness [c.sub.x], which both are functions of the tread stiffness and the carcass stiffness (which again is composed of the longitudinal, torsional and residual stiffness) [32].
The longitudinal relaxation time (T1, ms) and transverse relaxation time (T2, ms) of the synthesized PEG contrast agent solutions were measured using a 300 MHz (7.1 T) NMR spectrometer with a combination of measurements obtained in a large NMR tube (650 [micro]L of deuterium oxide to dilute the synthesized PEG contrast agents to different concentrations from 0.05 mM to 0.8 mM) and in a small tube (containing 50 [micro]L of benzene-D6).
In that work, the FID in the absence of radiation damping is assumed to be a simple exponential, and longitudinal relaxation is neglected.

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