radiofrequency pulse

ra·di·o·fre·quen·cy pulse

in nuclear magnetic resonance, a short electromagnetic signal used to change the direction of the magnetic field. See: sequence pulse.
Farlex Partner Medical Dictionary © Farlex 2012
References in periodicals archive ?
SPAIR is a hybrid technique combining the fat selectivity of CHESS and the inversion radiofrequency pulse of STIR.
In the process, the nuclear magnetization of amine (NH2) creatine protons is saturated by a radiofrequency pulse from the MRI.
A fit-to-theory program was used to measure temperature and reactant gas concentration, as a function of radiofrequency pulse and power using Coherent anti-Stokes Raman Spectroscopy (CARS).
3 and 4.) In addition to the time of flight effect contributing to the bright blood signal, blood remains virtually unaffected by the additional radiofrequency pulse because blood has a very low rate of magnetization transfer.[7,8,12]
Thermage uses radiofrequency pulses to heat subdermal collagen, causing it to contract and stimulating the growth of new collagen, in the process tightening the skin.
Nerves in the wall of the renal artery are ablated through the application of radiofrequency pulses to the renal arteries.
Moreover, arterial spin labeling (ASL) is a noninvasive alternative for imaging whole-brain cerebral perfusion that uses radiofrequency pulses instead of gadolinium to label inflowing arterial blood.[sup][4] Recent studies demonstrate that ASL can be used to quantify cerebral blood flow (CBF) values in the ischemic core and areas with perfusion/diffusion mismatch in patients with AIS.[sup][5],[6],[7],[8] In this study, ischemic penumbra was defined by decreased ASL CBF area, except in the restricted diffusion area.
It was obtained by varying the pulse duration of another phase-switched decoupling sequence, two-pulse phase modulation (TPPM), where radiofrequency pulses of length [[tau].sub.p] alternating between two phases separated by an angle [phi] were used [6].
Whole brain conventional MRI including diffusion tensor imaging (DTI) was performed on a 1.5T MRI scanner using a standard quadrature extremity coil/head coil for both transmission of radiofrequency pulses and signal reception.
In order not to exceed SAR limits at 3T, MRI pulse sequences are often modified to reduce power deposition either by decreasing the amplitude of the radiofrequency pulses and compensating by extending their duration (thus keeping the same flip angle) or by simply decreasing the flip angle of the radiofrequency pulses.
This imaging method uses strong magnetic fields, radiofrequency pulses and computers to produce detailed, cross-sectional images of the body.