Mark Jenkinson wrote:
> Hi,
>
> I've just responded to the question about using gradient-echo vs
> spin-echo.
> Unfortunately it is not easy or optimal to use our existing software
> for this.
> It is much better to use a spin-echo sequence.
>
> As for the asym time, it is the timing difference between the 180 degree
> pulses in the two spin-echo scans. The echo time (TE) is kept the same
> for both scans, but the 180 degree pulse is set at TE/2 for the
> symmetric
> scan (normal spin-echo) and set to (TE/2 + asym time) for the
> asymmetric scan.
Hi!
So, do I understand correctly that (with spin-echo) the asym time, used
to calculate the dwell-to-asym-ratio in fugue, should be equal to the
amount of time used to shift the 180 degree pulse (and not two times
that because the actual echo is delayed by two times the shift with
respect to the symmetric scan)? E.g., if the dwell time is 540 us and
the 180 degree pulse is shifted by 1170 us, the dwell-to-asym-ratio
should be 0.46?
Antti
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