While we're discussing spiral EPI, does anyone have this implemented
successfully on a Bruker system (or ASL for that matter - successfully...)?
Regards,
Greig
--
Dr Greig de Zubicaray
Centre for Magnetic Resonance
The University of Queensland
Brisbane, QLD 4072
AUSTRALIA
Tel: +61 (0) 7 3365 4250 [direct]
+61 (0) 7 3365 4100 [CMR]
Fax: +61 (0) 7 3365 3833
> From: Bob Turner <[log in to unmask]>
> Reply-To: Bob Turner <[log in to unmask]>
> Date: Thu, 2 Aug 2001 18:05:29 +0100
> To: [log in to unmask]
> Subject: Re: epi template for spiral data
>
> Dear Robert and Jon,
>
> Strictly speaking, the spiral and rectilinear versions of EPI have
> different image distortions. These arise from the endogenous magnetic field
> gradients produced by the sinus cavities and petrous bone. Both sequences
> give similar, though not identical, dropout regions. In the rectilinear
> case the endogenous gradients give additional distortions, but only in the
> phase-encode direction, while with spiral scan they contribute some
> blurring near the sinuses in all in-plane directions. However, for fast
> acquisitions, say 64 x 64 in less than 40 milliseconds at 1.5 T, the
> distortions are small for both methods, compared to the typical SPM smoothing.
>
> Ideally someone should construct a spiral template with typical acquisition
> parameters, which will contain typical spiral EPI distortions and dropout.
>
> Hope this helps.
>
> Bob Turner
>
>
>
>
>
> At 12:23 02/08/01 -0400, Robert Welsh wrote:
>> We do it all that time and don't see any issues. The T2* aspect of epi or
> spiral are in essence the same which is where the importance of the
> template come into play. The epi or spiral is just the readout scheme.
>>
>> Robert Welsh
>>
>>
>> -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>> Robert C. Welsh, PhD
>> Research Investigator
>> Department of Radiology
>> University of Michigan
>> (734) - 764 - 2412 (fax)
>> [log in to unmask]
>>
>>
>>
>>>>> jonathan david norton <[log in to unmask]> 08/02/01 12:07PM >>>
>> Dear colleagues,
>>
>> What, if any, problems would arise if spiral T2* images were
>> normalized to the EPI template included in SPM?
>>
>> Jon Norton
>>
>>
> Professor Robert Turner
> Wellcome Principal Research Fellow
> Wellcome Department of Cognitive Neurology
> Institute of Neurology
> 12 Queen Square
> London WC1N 3BG
> Tel: +44 (0)20 7833-7452
> Fax: +44 (0)20 7813-1445
> Website: http://www.fil.ion.ucl.ac.uk
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