Am I right in assuming that I could obtain absolute, tissue corrected choline concentration by performing the same calculations that is done for GABA but on Choline area under curve, that is to obtain a “ConcIU_CSFcorr” for choline?
Correct. You would just need to input the correct constants for the 3.2 ppm Cho peak in the formula. Have a look at the local function CalcIU in GannetFit.m (in the latest version) for reference.
So this would involve finding a reference for the constants then. I found Li et al (2013) JMID but if anyone knows of a more suitable reference I am open to suggestions.
However, I am afraid I cannot figure out what N_H_Metab represents.
Here is the full reference:
Li, Y. (2013). T1 and T2 Metabolite Relaxation Times in Normal Brain at 3T and 7T. Journal of Molecular Imaging & Dynamics, 02(02). https://doi.org/10.4172/2155-9937.S1-002
Thank you for the tip to look into Osprey!
I have to confess that I am clueless about the N_H_Metab variable, but I take it that your response about nine protons is in relation to that?
The N_H_Metab constant is the number of hydrogen protons that give rise to the signal of interest. For the 3.2 ppm Cho peak, there are 9 protons. You need to account for this as the signal areas scale with the number of hydrogen protons.
Please see the Gannet documentation website for further details of all the variables.