# Signal intensity in mri image

**URL:** https://discourse.slicer.org/t/signal-intensity-in-mri-image/26256
**Category:** Support
**Created:** [November 15, 2022, 7:49pm UTC](https://discourse.slicer.org/t/signal-intensity-in-mri-image/26256 "2022-11-15T19:49:36Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![hannahmed](https://avatars.discourse-cdn.com/v4/letter/h/85e7bf/32.png) [@hannahmed](https://discourse.slicer.org/u/hannahmed)
#### Post date: [November 15, 2022, 7:49pm UTC](https://discourse.slicer.org/t/signal-intensity-in-mri-image/26256/1 "2022-11-15T19:49:36Z")

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Hello everyone,

how do I detect the signal intensity in an MRI image in order to be able to calculate the signal-to-noise-ratio (SNR) and -contrast-to-noise-ratio (CNR) in for example the liver and the air?

I’d appreciate any help! Thank you.

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### Author: ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)
#### Post date: [December 1, 2022, 7:16am UTC](https://discourse.slicer.org/t/signal-intensity-in-mri-image/26256/2 "2022-12-01T07:16:46Z")

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You can measure SNR in MRI using the [SNRMeasurement extension](https://www.slicer.org/wiki/Documentation/Nightly/Modules/MRI_SNR_Measurement).