we were collecting metabolite data with hercules in anterior cingulate cortex and observed that the incoming data were completely dominated by a water peak – does anyone know what could have caused this? We confirmed the contrast field in the program card was set to ‘water saturated’ and we have used this same sequence for more than 45 other subjects without this issue
Hi Stephanie,
I think the shim here is the much bigger problem. This linewidth is far too big. What did the FWHM value say? Did you play with the manual shim as we discussed the other day?
If the shim is off by this much, it’s not particularly surprising to me that the water suppression doesn’t work well… but again, that’s the least of your problems with a shim like that.
Cheers,
Georg
thank you for the feedback!! the FWHM was 14.5. We did try playing with manual shim in the interactive tab but weren’t’ able to change much … we will try playing around with this more! we did try re-shimming after moving the voxel to a slightly different position and the shim the second time was 14.0.
OK, that shouldn’t be too bad, but the actual in-line display still tells me this line is super-broad. Did you hit ‘Apply’ in the right column after you performed the shim?