precession

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Related to Free precession: precessional, Torque-free precession

precession

An MRI term for the relatively slow gyration of the axis of a spinning body, which traces out a conical configuration. Precision is caused by the application of a torque which tends to change the direction of the rotation axis and is continuously directed at right angles to the plane of the torque. The magnetic moment of a nucleus with spin will experience such a torque when inclined at an angle to the magnetic field, resulting in precession at the Larmor frequency.

pre·ces·sion

(prē-sesh'ŭn)
The secondary spin of magnetic movements around the main magnetic field.
References in periodicals archive ?
These novel results on 4U 0142+61 can be consistently interpreted by assuming that this magnetar is axisymmetric, and is undergoing free precession with a slip period of T = 55 ksec.
Application of missing pulse steady state free precession to the study of renal microcirculation.
[18] Haacke EM, Wielopolski PA, Tkach JA, Modic MT Steady-state free precession imaging in the presence of motion: application for improved visualization of the cerebrospinal fluid.
Whereas in the lower energy case [T.sub.2] is simply shortened, in the higher energy case the shape of the FID can be dramatically modified because the transverse magnetization can increase during the free precession. Here we are concerned with the possible effect of radiation damping on FID measurements, in particular on the determination of [P.sub.stc], but al so on the measurement of cell relaxation times.
Improving contrast to noise ratio of resonance frequency contrast images (phase images) using balanced steady-state free precession. Neuroimage 2011; 54: 2779-88.
One is gradient echo imaging with balanced steady state preservation of residual transverse magnetization (steady state free precession, SSFP).
Bright-blood NCE MRV pulse sequences include time-of-flight (TOF) gradient recalled-echo (GRE) or spoiled gradient recalled (SPGR) sequences as well as steady state free precession (SSFP) sequences.