Hi Mark,
Thanks for the detailed reply, it was very helpful.
cheers,
wolf
Mark Jenkinson wrote:
> 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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