Reliability of MRS to distinguish Glu vs. Gln

My understanding is that MRS struggles to distinguish Glu and Gln and that it is safest to use Glx only. I am using Osprey for my MRI analysis which gives Glu, Gln and Glx separately. Would you advise still only reporting Glx, or are the Glu reliable enough on their own. Some of my Gln results are coming out as 0 so I suspect Gln is not helpful alone. Many thanks!

Hi James,

The answer to that question will depend on many different factors, including the field strength, localization sequence, echo time, brain region (shim condition), signal-to-noise ratio (voxel volume and measurement duration) and finally the participants you are interested in studying.

Gln is present at lower levels than Glu in normal brain, and seeing it estimated at 0 is not uncommon. If your data quality isn’t very high, I would strongly suggest reporting Glx and not attempting to report separately.


Hi Georg,

Thank you for the quick reply, that’s very helpful.



Hi James,
here is a paper about the investigation of some parameters (at phantoms) Georg mentioned ( All in all, especially Gln is a great challange to fit.