In-phase and out-of-phase sequences

Dr Ian Bickle 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. 

Applications

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. Loss of signal intensity between the in-phase and out-of-phase MR images indicates fat. Examples where IP-OOP sequences are useful include 1,2:

Imaging technology

Article information

rID: 42534
Tag: refs, refs, refs
Synonyms or Alternate Spellings:
  • in and out of phase
  • Opposed-phase imaging
  • Chemical shift cancellation artifact
  • 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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Cases and figures

  • Case 1: lipid-rich left adrenal adenoma
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  • Case 2: lipid-poor hepatic adenoma
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  • Case 3: fatty liver
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  • Case 4: lipid-rich hepatic adenoma
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  • Case 5: focal fatty change
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  • Case 6: lobar distribution pattern of the focal fatty infiltration
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  • Case 7: lipid-rich right adrenal adenoma
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  • Case 8: hemochromatosis
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  • Case 9: lipid-rich left adrenal adenoma
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  • Case 10: primary hemochromatosis
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  • Case 11: vertebral metastases from breast cancer
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