I’m trying to analyze data collected with the CMRR mega-press sequence (Tokyo release) on an older Siemens 3T system. The twix files were not archived. For each scan, I have two rda files - one on-resonance and one off-resonance. When I try to load them as “MRS Data” using the Interactive Osprey jobfile generator, it will only take one file per dataset. Does anyone know how I can get it to take both the on-resonance and off-resonance rda files?
Hi Rick,
I’m not sure how well this is supported by our current version of the job file generator - but if you are specifying the job as a .m file instead, which is the preferred way of setting up analyses (see the documentation), you can do this.
Instead of a single file, you need to specify a directory that only contains the two RDA files for this dataset and nothing else (see here).
I will say that this way of analyzing MEGA data is quite unlikely to yield good results, since the edit-ON and edit-OFF spectra will be averaged on-scanner without any kind of individual transient alignment. In my experience, that is almost guaranteed to introduce substantial subtraction artefacts that even good modeling cannot account for.
Happy to look at some difference spectra and figure out how bad it is.
Cheers,
Georg
Hi Georg,
Ahh, thanks! That is the information I needed. Just learning Osprey and didn’t know the job file generator was not the preferred way to set up an analysis. I’ll have to brush-up on matlab, though.
Regarding the use of rda files, I’ll make sure the group archives the twix files going forward. For their existing rda-ony archives of MEGA scans, I’ve developed a couple of work-arounds that minimize the detrimental effects of averaging before aligning.
All the best,
Rick