[CODE SUBMISSION] Filter the spectrum edge artefact from Siemens spectra

Data Processing
1

I want to submit a Matlab function to remove the Siemens spectral smily or sad artefacts at the spectrum edges.
Every spectrum FID from Siemns scanners has a time reveresed mini FID at
the end.
This is an artefact of the digital filtering.

This is a problem for several reasons:

  1. If the FID is truncated or adpodized the edges of the spectrum will turn down or up.
  2. The noise estimates in jMRUI will be wrong. AMARES and other quantification choices in jMRUI use the tail end of the FID to estimate noise.
  3. Frequency domain fitting baseline splines will be influenced and this can lead to quantification errors

NOTE: As a consequence of point 2, the noise estimates of FIDs treated with this function will also be wrong.

Unsmile_Siemens0.pdf (84.6 KB)
Unsmile_Siemens1.pdf (156.9 KB)

1 Like
2

Hi Ron,

Good to hear from you, and thank you for your submission. I’ve seen this one before in my own datasets and was always annoyed by it, but never annoyed enough to do something about it, so this will be very useful! :wink:

Would you mind sharing the code itself (either by packing it up and attaching it here, by pointing to your repository, or by sending via e-mail)? You can find the detailed instructions here.

Looking forward!
Best wishes,
Georg