Be precise about B1plusmap, B1minusmap and B1map.

[Gilles86]

Hey,

I notice that there are some inconsistencies in the spec right now. So in general, people seem to use B1map and B1plusmap interchangeably. But for the MPM examples, we use B1minusmap. What should we do here? Replace everything with B1plusmap?

-Gilles

[agahkarakuzu]

So the options would be:

1. B1map and B1minusmap
2. B1map and Sensmap
3. B1plusmap and B1minusmap
4. (B1map + B1plusmap) and B1minusmap

First off, would 4 be possible? I've almost never seen anyone who uses B1map to refer to B1minusmap. Can we somehow accommodate that interchangeability in the spec? I know this is not ideal, but don't know which one would be more expensive. Changing everything or having two labels pointing to the same entity?

[Gilles86]

I think B1map is not in the spec yet. Only in some of our other examples. So I really prefer option 3.

Stupid qustion:are the B1minusmaps in the MPM examples really B1 minus maps?

Let's discuss this in the meeting later.

On Wed, 15 May 2019, 16:32 Agah, notifications@github.com wrote:

So the options would be:

1. B1map and B1minusmap
2. B1map and Sensmap
3. B1plusmap and B1minusmap
4. (B1map + B1plusmap) and B1minusmap

First off, would 4 be possible? I've almost never seen anyone who uses B1map to refer to B1minusmap. Can we somehow accommodate that interchangeability in the spec? I know this is not ideal, but don't know which one would be more expensive. Changing everything or having two labels pointing to the same entity?

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[agahkarakuzu]

Stupid qustion:are the B1minusmaps in the MPM examples really B1 minus maps?

Need to go back to method paper to find out.

Let's discuss this in the meeting later.

Cool!

[agahkarakuzu]

+1 on option 3 as well then.

[agahkarakuzu]

From the original paper:

The MPM comprised three multi-echo 3D FLASH (fast low angle shot) scans, one RF transmit field map and one static magnetic (B0) field map scan (Weiskopf et al., 2011).

The h-MRI toolbox allows generation of a B1minus map (N4ITK kind of bias correction) if inputs for B1map fitting (3D segmented EPI) are not provided by user. At 3T, B1+ and B1- are fairly comparable, but not quite sure how processing advances in that case.

[Gilles86]

OK, but a standard MPM protocol then apparently includes a B1 plus map right?

On Wed, 15 May 2019, 16:56 Agah, notifications@github.com wrote:

From the original paper:

The MPM comprised three multi-echo 3D FLASH (fast low angle shot) scans, one RF transmit field map and one static magnetic (B0) field map scan (Weiskopf et al., 2011).

The h-MRI toolbox allows generation of a B1minus map (N4ITK kind of bias correction) if inputs for B1map fitting (3D segmented EPI) are not provided by user. At 3T, B1+ and B1- are fairly comparable, but not quite sure how processing advances in that case.

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[KirstieJane]

@christophephillips - can you answer this question? What is expected for the MPM protocol?

[lazaral]

As far as I understand MPM/hMRI uses both transmit and receive fields (although if I’m not wrong Weiskopf 2013 only used B1+, B1- was added after and is now part of hMRI in Tabelow 2019). The MPM protocol I use definitely includes both. I’d love to hear confirmation from actual MPM experts like @ChristophePhillips  though!