In-phase and out-of-phase sequences

Dr Henry Knipe and Dr Bruno Di Muzio et al.

In-phase (IP) and out-of-phase (OOP) sequences correspond to paired MRI gradient echo (GRE) sequences obtained with the same repetition time (TR) but with two different echo time (TE) values. 


The main application of the IP-OOP sequences is to identify pathological (microscopic) fat content of tissues in the abdomen by showing signal intensities drop on the OOP images compared to the IP images. Examples where IP-OOP sequences are useful include 1,2:

Physics and Imaging Technology: MRI

Factors affecting T1

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Article information

rID: 42534
Section: Physics
Tag: refs
Synonyms or Alternate Spellings:
  • Opposed-phase
  • In-phase and out-of-phase sequences
  • In-phase/out-of-phase
  • In-phase and out-of-phase
  • IP and OOP
  • IP/OOP
  • IP-OOP

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