Multislice Sequences

[felixlandmeyer]

Does MRZero support multislice sequences?

I have modified the mr0_FLASH_2D_seq.ipynb file to generate, simulate and reconstruct a multislice FLASH.

When I reconstruct the simulated data, each slice image contains the sum of all expected slice images.

I can't upload the Jupyter notebook with the modified sequence, so I exported it as a Python file.
Of course, it could also be that the sequence is buggy.

mr0_flash_2d_seq.txt

[SWeinmueller]

We do not currently support multislice sequences. All pulses are treated as instant pulses and excite the entire phantom.

[joergfelder]

That's a real pitty given that I would like to use pulseq sequences for simulations as well as measurements on the scanner. Could you think of a workaround? Maybe setting all RF pulses for a slice other than the currently simulated slice to zero amplitude and repeating this step for all slices? Is there a plan to integrade 3D simulations in the future?

[mzaiss]

We have ideas for supporting this. its not that complicated but we currently dont find the time.
it is a bit tricky though to properly do the relaxation without being very ineffective in runtime.
Is runtime am issue for you?
if you just run the forward muktiskice sequence as it is for a whole brain, how long does it take?

[joergfelder]

Hi Moritz, I am trying to simulate with full brain coverage using 32 slices from the brainweb phantom. With this the simulation takes roughly 40 minutes on the CPU. I think using a GPU would speed it up significantly - the one on my computer does not have enough memory though. This is why I have not tried it yet ... Thanks for the quick reply, Jörg Am 14.07.2025 12:41 schrieb mzaiss ***@***.***>: We have ideas for supporting this. its not that complicated but we currently dont find the time. it is a bit tricky though to properly do the relaxation without being very ineffective in runtime. Is runtime am issue for you? if you just run the forward muktiskice sequence as it is for a whole brain, how long does it take? — Reply to this email directly, view it on GitHub<#107 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/ALVYMRE7PS2VARLQHTHIEHT3IOCNNAVCNFSM6AAAAABUZWNRYOVHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTGNZVGA4DGMI>. You are receiving this because you commented.Message ID: ***@***.***>

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