Specific documentation section for sequence simulation

[aTrotier]

Feature Request

Hi,
We saw a lot of issues from imperfect choice of simulation parameters (which are not really available in the UI)

This issue will list some of them in order to see if we can create a dedicated section :

1. Gradient spoiled sequence issues

• solved by either up sampling of phantom
• increase TR to get a relaxation spoiled sequence

2. Rf step phase simulation discrepancy between slice profile simulation and signal simulation

• was observed with SMS sequence
• rf time step need to be reduced for signal simulation
• related issue : Slice offset does not works when the frequency offset is applied to rf.signal #557

3. 3D sequences

• a lot of time the slab is larger than the object
• it is possible to increase the object
• maybe the default 3D should be whole phantom
• related issue : Multi-slice acquisition with 3D phantom #474

4. Multi-contrast acquisition

• how to change the label in the rawacquisitiondata

Do you have other points that you noticed ?

[cncastillo]

Rf step phase simulation discrepancy between slice profile simulation and signal simulation
was observed with SMS sequence
rf time step need to be reduced for signal simulation

Which sequence did you use for this? This PR #612 defines a new BlochMagnus4 method that should solve this (more accurate numerical integration). I would really like to incorporate an example like that for ISMRM :D

[cncastillo]

We saw a lot of issues from imperfect choice of simulation parameters (which are not really available in the UI)

All parameters in sim_params should be displayed in the UI, which ones do you mean?

[aTrotier]

Which sequence did you use for this? This PR #612 defines a new BlochMagnus4 method that should solve this (more accurate numerical integration). I would really like to incorporate an example like that for ISMRM :D

The sequence is available in the zip file of this issue I think : #557
I can create another example if required

[cncastillo]

Awesome! let me try that one

[aTrotier]

We saw a lot of issues from imperfect choice of simulation parameters (which are not really available in the UI)

All parameters in sim_params should be displayed in the UI, which ones do you mean?

I didn't see them before clicking on simulate :

An even after I can't edit them so for users they might not now that they could change them with sim_ui[]=...

[cncastillo]

ooo that is a bug a totally forgot. Now in #630.

[aTrotier]

Another issue I saw a lot is that sometimes the estimated trajectory estimates a matrix size nz=2. I guess it is some rounding errors due to the slice selection acquisition.

If I saw the problem again, I will try to keep the script :)