In-phase and out-of-phase sequences

Last revised by Mohamed Saber ◉ on 31 Dec 2020

Citation, DOI, disclosures and article data

Citation:

Di Muzio B, Saber M, Bickle I, et al. In-phase and out-of-phase sequences. Reference article, Radiopaedia.org (Accessed on 30 Mar 2025) https://doi.org/10.53347/rID-42534

DOI:

https://doi.org/10.53347/rID-42534

Permalink:

https://radiopaedia.org/articles/42534?embed_domain=external.radpair.com%2527%255b0%255d

rID:

42534

Article created:

26 Jan 2016, Bruno Di Muzio ◉

Disclosures:

At the time the article was created Bruno Di Muzio had no recorded disclosures.

View Bruno Di Muzio's current disclosures

Last revised:

31 Dec 2020, Mohamed Saber ◉

Disclosures:

At the time the article was last revised Mohamed Saber had no recorded disclosures.

View Mohamed Saber's current disclosures

Revisions:

18 times, by 13 contributors - see full revision history and disclosures

Sections:

Imaging Technology

Tags:

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Synonyms:

In-phase and out-of-phase sequences
In-phase/out-of-phase
IP and OOP
IP/OOP
IP-OOP
In-phase and out-of-phase
Opposed-phase
Chemical shift cancellation artifact
Opposed-phase imaging
in and out of phase

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: