Neuropoly_ep2d_bold_advshim sequence - could not get good images of the phantom

MRI Acquisition
1

Hello Julien and NeuroPoly team,

We have been evaluating a C2P pulse sequence for fMRI with advanced shimming that you developed to be used with the Shimming Toolbox (thank you!) Unfortunately, we’ve been unable to get any recognizable images of a cylindrical phantom even with dynamic shimming disabled. We have a Cima.X scanner (XA61A software). Here is how it looks with our protocol parameters (120x120 matrix, 7/8 partial fourier, SMS 2, PE accel 2):

neuropoly_screenshot_1
neuropoly_screenshot_11644×1870 159 KB

And here how it looks with default parameters:

neuropoly_screenshot_2
neuropoly_screenshot_21676×1932 26.9 KB

Dynamic shimming is turned off in both cases. Same prescription looks fine with CMRR EPI pulse sequence. Do you have any thoughts on what might be wrong or how to troubleshoot it?

Thank you,

Eugene

2

Hi @eugene_o,

Thank you for reporting this issue. We ran into a similar problem in the past, and I remember it was due to a bug in the sequence when using it on XA61 specifically, because of the different gradient system which requires a different management of gradient variables for slicewise shimming. We fixed it in a more recent version of the sequence.

Can you let me know what version of the sequence you are running?

Julien

1 Like
3

Hi Julien,

I am using 0.2 version. I will test 0.3 and will let you know if it solves this

Thank you!
Eugene