help with RB1map

[Dr Cyril, Pernet]

Dear qMRI gurus,

As we acquire MP2RAGE data, we collect B1map, except that we have 2 sequences, a 'B1map' (left below) and a 'tfl_b1map' (right below) which produces a magnitude image and a flip angle map. While Siemens told me this is receiver, the fact that there is two parts and the definition for transmit map makes me think I should store this as TB1map (https://bids-specification.readthedocs.io/en/stable/04-modality-specific-files/01-magnetic-resonance-imaging-data.html#anatomy-imaging-data) after multiply those two together?

what suffixes to use to store those images? (if nothing fine, it will go to source)

thx

cyril

-- 
Dr Cyril Pernet, PhD, OHBM fellow, SSI fellow
Neurobiology Research Unit, 
Building 8057, Blegdamsvej 9
Copenhagen University Hospital, Rigshospitalet
DK-2100 Copenhagen, Denmark

wamc...@gmail.com
https://cpernet.github.io/
https://orcid.org/0000-0003-4010-4632

[Dr. Tobias Leutritz]

Dear Cyril,

please consult the code for producing B1 maps from those sequences here (within the hMRI-toolbox - could also be used to produce the maps standalone, i.e. independet from other map creation):

https://github.com/hMRI-group/hMRI-toolbox/blob/master/hmri_create_b1map.m

The referenced b1input consits of (1st) an anatomical reference image and (2nd) the flip angle map, which have to be scaled according to the used flip angle during acquisition.

Hope this helps!

Best,
Tobias :-)

----- Ursprüngliche Mail -----
> Von: "Dr Cyril, Pernet" <wamc...@gmail.com>
> An: bids-di...@googlegroups.com
> CC: "Agâh Karakuzu" <agahka...@gmail.com>, "c phillips" <c.phi...@uliege.be>
> Gesendet: Freitag, 15. September 2023 09:08:41
> Betreff: [bids-discussion] help with RB1map

> Dear qMRI gurus,
>
> As we acquire MP2RAGE data, we collect B1map, except that we have 2
> sequences, a 'B1map' (left below) and a 'tfl_b1map' (right below) which
> produces a magnitude image and a flip angle map. While Siemens told me
> this is receiver, the fact that there is two parts and the definition
> for transmit map makes me think I should store this as TB1map
> (https://bids-specification.readthedocs.io/en/stable/04-modality-specific-files/01-magnetic-resonance-imaging-data.html#anatomy-imaging-data)
> after multiply those two together?
>
> what suffixes to use to store those images? (if nothing fine, it will go
> to source)
>
> thx
>
> cyril
>
>

> --
> Dr Cyril Pernet, PhD, OHBM fellow, SSI fellow
> Neurobiology Research Unit,
> Building 8057, Blegdamsvej 9
> Copenhagen University Hospital, Rigshospitalet
> DK-2100 Copenhagen, Denmark
>
> wamc...@gmail.com
> https://cpernet.github.io/
> https://orcid.org/0000-0003-4010-4632
>

> --
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[Dr Cyril, Pernet]

Hi Tobias

Just to be clear, my so called 'B1map' from Siemens is indeed just the
amplitude map (what I thought) used as ref -- the two images will thus
go to /source, and the computed T1map to /derivatives. I found it
'interesting' that there is no agreed name for the flip angle map to be
stored as raw - or do I misread the spec?

thank you

Cyril

[Dr. Tobias Leutritz]

Dear Cyril,

isn't the whole topic connected with the TB1map, since we observe the transmit field?

Best,
Tobias :-)

----- Ursprüngliche Mail -----
> Von: "Dr Cyril, Pernet" <wamc...@gmail.com>

> An: "bids-discussion" <bids-di...@googlegroups.com>, "Tobias Leutritz" <tleu...@cbs.mpg.de>

> CC: "Agâh Karakuzu" <agahka...@gmail.com>, "c phillips" <c.phi...@uliege.be>

> Gesendet: Mittwoch, 20. September 2023 14:31:22
> Betreff: Re: [bids-discussion] help with RB1map

[Dr Cyril, Pernet]

No idea, someone started collecting MP2RAGE and I saw we recompute and
correct by saving the amplitude/phase of each inversion + B1map, so I
asked our local Siemens contact to set it up and that's what I got --
she told me it is receiver map not transmit, RB nor TB, so you are
confusing me even more :-( I'm a poor fMRI guy