1.7 ppm artifact in B and D HERMES experiments

Analysis / Modeling
1

Hi everyone,

I was wondering if anyone had an idea of what would cause the following artifact. A recent HERMES scan of an mPFC voxel showed a strange symmetrical bump centered around 1.7 ppm. This is only seen in the B and D experiments of the sequence. The rest of the data is relatively clean, with reasonable SNR and line widths. I have only seen a similar artifact once across dozens of scans.

I have attached the sum spectrum after processing with Osprey 2.5.0. Any ideas? Thanks!

  • Keith Jones

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2

We’ve seen this before, and don’t really have a very strong explanation for it. My best guess is that the 1.9-ppm editing pulse accidentally refocuses some adjacent lipid signals that end up in the spectrum (possibly also with a phase-cycle dependency since we see two distinct ones), but that’s really the only thing that comes to mind. @richardedden ?