Hi Lino,
If your values are from -pi to pi then there are two problems:
1 - you haven't unwrapped your phase with prelude
2 - it isn't scaled to be in radians *per second*, but is just in radians
Have a look at the page:
http://www.fmrib.ox.ac.uk/fsl/fugue/feat_fieldmap.html
which explains how to prepare phasemaps for input into FEAT.
This has changed in the last release, and so maybe you haven't caught up
with this before.
All the best,
Mark
lino becerra wrote:
> Hi Steve:
> field map image is in rad/s (-pi to pi), since we only have the phase
> difference image, we created the phase4d image with the first image
> being just
> ones and the second the field map one.
> lino
>
>
>
> On Mar 12, 2007, at 8:14 AM, Steve Smith wrote:
>
>> Hi - the FEAT GUI requires that the fieldmap image should be a 3D
>> image with units of rad/s - it sounds like maybe you haven't quite
>> prepared it in this way?
>>
>> Cheers.
>>
>>
>> On 9 Mar 2007, at 20:28, lino becerra wrote:
>>
>>> Hi:
>>> We are having some trouble using fugue on our data.
>>> It seems that only part of the epi image gets corrected and that
>>> what seems unwarped is also displaced.
>>> We have mag/phase images from a Siemens 3T, we prelude the phase
>>> image and create a phase4d with the first image being 1's.
>>> The phase image looks fine.
>>> Any suggestions would be appreciate it.
>>> Thanks !
>>>
>>> lino
>>>
>>>
>>>
>>>
>>> Any information, including protected health information (PHI),
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>>> and delete the material from any computer.
>>
>>
>>
>> ----------------------------------------------------------------------
>> -----
>> Stephen M. Smith, Professor of Biomedical Engineering
>> Associate Director, Oxford University FMRIB Centre
>>
>> FMRIB, JR Hospital, Headington, Oxford OX3 9DU, UK
>> +44 (0) 1865 222726 (fax 222717)
>> [log in to unmask] http://www.fmrib.ox.ac.uk/~steve
>> ----------------------------------------------------------------------
>> -----
>>
>
>
>
> Any information, including protected health information (PHI),
> transmitted in
> this email is intended only for the person or entity to which it is
> addressed
> and may contain information that is privileged, confidential and/or
> exempt
> from disclosure under applicable Federal or State law. Any review,
> retransmission, dissemination or other use of or taking of any action
> in reliance
> upon, PHI by persons or entities other than the intended recipient
> is prohibited. If you received this email in error, please contact the
> sender
> and delete the material from any computer.
If you look at the
lino becerra wrote:
> Hi Steve:
> field map image is in rad/s (-pi to pi), since we only have the phase
> difference image, we created the phase4d image with the first image
> being just
> ones and the second the field map one.
> lino
>
>
>
> On Mar 12, 2007, at 8:14 AM, Steve Smith wrote:
>
>> Hi - the FEAT GUI requires that the fieldmap image should be a 3D
>> image with units of rad/s - it sounds like maybe you haven't quite
>> prepared it in this way?
>>
>> Cheers.
>>
>>
>> On 9 Mar 2007, at 20:28, lino becerra wrote:
>>
>>> Hi:
>>> We are having some trouble using fugue on our data.
>>> It seems that only part of the epi image gets corrected and that
>>> what seems unwarped is also displaced.
>>> We have mag/phase images from a Siemens 3T, we prelude the phase
>>> image and create a phase4d with the first image being 1's.
>>> The phase image looks fine.
>>> Any suggestions would be appreciate it.
>>> Thanks !
>>>
>>> lino
>>>
>>>
>>>
>>>
>>> Any information, including protected health information (PHI),
>>> transmitted in
>>> this email is intended only for the person or entity to which it is
>>> addressed
>>> and may contain information that is privileged, confidential and/ or
>>> exempt
>>> from disclosure under applicable Federal or State law. Any review,
>>> retransmission, dissemination or other use of or taking of any
>>> action in reliance
>>> upon, PHI by persons or entities other than the intended recipient
>>> is prohibited. If you received this email in error, please contact
>>> the sender
>>> and delete the material from any computer.
>>
>>
>>
>> ----------------------------------------------------------------------
>> -----
>> Stephen M. Smith, Professor of Biomedical Engineering
>> Associate Director, Oxford University FMRIB Centre
>>
>> FMRIB, JR Hospital, Headington, Oxford OX3 9DU, UK
>> +44 (0) 1865 222726 (fax 222717)
>> [log in to unmask] http://www.fmrib.ox.ac.uk/~steve
>> ----------------------------------------------------------------------
>> -----
>>
>
>
>
> Any information, including protected health information (PHI),
> transmitted in
> this email is intended only for the person or entity to which it is
> addressed
> and may contain information that is privileged, confidential and/or
> exempt
> from disclosure under applicable Federal or State law. Any review,
> retransmission, dissemination or other use of or taking of any action
> in reliance
> upon, PHI by persons or entities other than the intended recipient
> is prohibited. If you received this email in error, please contact the
> sender
> and delete the material from any computer.
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