Preferred Label : ghost;
RADLEX synonyms : image harmonic artifact; image harmonic; replica; ghost artifact; replica artifact; phase shift artifact; coherent ghost;
Definition : Ghosts are defined as secondary images appearing in locations that differ from the
primary image. Ghosts occur along phase encoding direction regardless of direction
moved. Distance between ghosts increases as the number of periodic motions between
TRs increases – hence, increases with frequency of motion and with TR. The distance
also increases with number of signal averages. Ghosts may be high or low signal depending
on whether they are in phase or out of phase with the object they overlie. If the
TR is so short that motion does not repeat between excitations, then periodic motion
causes edge smearing (as with random motion) rather than ghost generation.;
Origin ID : RID11426;
Currated CISMeF NLP mapping
Ghosts are defined as secondary images appearing in locations that differ from the
primary image. Ghosts occur along phase encoding direction regardless of direction
moved. Distance between ghosts increases as the number of periodic motions between
TRs increases – hence, increases with frequency of motion and with TR. The distance
also increases with number of signal averages. Ghosts may be high or low signal depending
on whether they are in phase or out of phase with the object they overlie. If the
TR is so short that motion does not repeat between excitations, then periodic motion
causes edge smearing (as with random motion) rather than ghost generation.
