Hi,
This program calculates signal loss as a dimensionless fraction such
that if you multiply
the image without loss by this image then you would get the equivalent
image with
signal loss. Hence the output is actually more like signal retained.
That is, a value of
1 in the output means no signal loss, while a value of 0 means all the
signal was lost.
The default value of TE is set to a ridiculous value so that you can't
run it sensibly
with the default, as you really must specify a correct TE value and
there is no
typical value that would work for any sizable number of people.
This program is very simple in concept, and just works out the signal
loss factor
for the through slice dephasing, based on an ideal slice selection -
which is a sinc
function. Any number of papers/books will probably contain this,
although the
formula here is derived from scratch given that I do several slightly
tricky things
with estimating field-gradients separately in different sub-components
of the voxel.
Hope this helps.
All the best,
Mark
wolf zinke wrote:
> Hi all,
>
> I came across the sigloss tool, which might do exactly what I want.
> So, instead of reinventing wheels I would like to understand this
> program a bit better.
>
> The output is in the range of 0 to 1 if I got everything right. What
> is the dimension and how do I interpret the values.
> There is the --te option. Do I understand it right that this results
> in an estimate of signal loss for a given TE? Why is it than set per
> default to 1s, which is far beyond normally used values? Is there any
> reference this program is based on?
>
> Thanks in advance for your help,
> wolf
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