When using a publicly available experimentally measured MM basis, are differences among different people considered?

Hi everyone,

I am conducting 7T short TE STEAM experiments to detect GABA. Following the recommendations, I have decided to use experimentally measured MM during the fitting. As I am unfamiliar with experimentally measuring MM, I initially want to use publicly available MM basis or those permitted by the authors.

Lately, I have been troubled by a question: even if I recruit volunteers in the same age range and place voxels in the same brain region as the authors did, considering that these two groups of volunteers are completely different individuals, to what extent would experimentally measured MM basis introduce inaccuracies in fitting low-concentration metabolites such as GABA?

May I ask if anyone has considered this question or could share relevant papers with me? I would greatly appreciate it.

Differences between different people are not considered, no. The MM profile is thought to be relatively stable between individuals (and across age ranges), but there is not really a huge amount of data out there. The use of one rigid basis function is certainly a big compromise.

We recently published a paper on using subject-specific MM basis functions here: Feasibility and implications of using subject-specific macromolecular spectra to model short echo time magnetic resonance spectroscopy data - PubMed (nih.gov), there are a few references for further reading in it.

Thank you, Georg. It’s just what I need.