SNR and fit quality metric

Data Processing
1

Hello,

I am running MEGAPRESS on a Siemens prisma 3T.

Is it possible to get the SNR and/or fit quality metric for more than just tCr and GABA? Is there a metric that can be computed for each metabolite?

Also what is the difference between the amplMets and tCr values in the QuantifyResults output?

Thank you!

2

Hi @ZanettaK1,

Thanks for reaching out. I assume from the variable names you are referring that you are using Osprey ;).

The current version Osprey does not report metabolite specific quantification error metrics, e.g. Cramer-Rao Lower Bounds. You could change the model algorithm in the jobfile to LCModel to get those values.

The differences in the output tsv files are the following. amplMets contains the raw signal amplitudes as computed by the linear-combianiton algorithm in arbitrary units. tCr contains the creatine referenced values (everything is normalized by the tCr amplitude of the edit-OFF scan.) This is also described in the .json files that accompany the tsv files.

Best,
Helge