Hi Doug,
All other things being equal, if you switch from AP to RL phase encoding
in an axial acquisition, then the PE direction will switch from the y-axis
to the x-axis in the images.  It doesn't really have anything to do with
Siemens, since the images are written out in a standard anatomical
orientation, not according to which axis was readout and which was phase
encode.

Hope that helps,
-MH

 
Michael Harms, Ph.D.

-----------------------------------------------------------
Conte Center for the Neuroscience of Mental Disorders
Washington University School of Medicine
Department of Psychiatry, Box 8134
660 South Euclid Ave.           Tel: 314-747-6173
St. Louis, MO  63110                    Email: mha...@wustl.edu




On 11/13/12 3:46 PM, "Douglas N Greve" <gr...@nmr.mgh.harvard.edu> wrote:

>I guess it is possible that Siemens is doing something funny with the
>images. I've never used sagittal before.
>
>On 11/13/2012 12:51 PM, Clark Fisher wrote:
>> I'm using a script that calls unpacksdcmdir.  Maybe there is some
>>setting in our config file that forces the orientation?  Nothing obvious
>>though.
>>
>>
>> On Nov 13, 2012, at 12:03 PM, Douglas N Greve wrote:
>>
>>> I'm a little confused as to why the rows are not the phase encode
>>>direction to begin with. What did you use to convert the dicoms to
>>>nifti?
>>> doug
>>>
>>> On 11/13/2012 11:59 AM, Clark Fisher wrote:
>>>> Thanks Doug,
>>>>
>>>> Would the proper way to handle this then be to switch the rows and
>>>>columns before unwarping, then switch them back before the further
>>>>processing steps?
>>>>
>>>> -Clark
>>>>
>>>>
>>> -- 
>>> Douglas N. Greve, Ph.D.
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>>> gr...@nmr.mgh.harvard.edu
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>
>-- 
>Douglas N. Greve, Ph.D.
>MGH-NMR Center
>gr...@nmr.mgh.harvard.edu
>Phone Number: 617-724-2358
>Fax: 617-726-7422
>
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