[Insight-users] itk::ImageSeriesReader - Use of ReverseOrderOn to Properly Orient Constructed Volume using a CT Data-set

[M. Wirtzfeld]

Good afternoon,

I have a question regarding the use of the itk::ImageSeriesReader class.

I have two sets of images, a CT data-set and an MR data-set.  Both 
data-sets are of a single volume and consist of a sequence of DICOM images.

My registration application reads a single DICOM image that acts as the 
fixed-image (in context of ITK), while the set of DICOM images is read 
using the aforementioned class in order to construct the volume or 
moving-image (again in the ITK context).

When the registration application executes using the MR data-set, 
registration occurs.  However, when the CT data-set is used, the method 
"ReverseOrderOn" must be called to reverse filename order, otherwise the 
volume appears to be "flipped" and there is no overlap between the 
fixed- and moving-images.

I use the itk::ImageFileReader class to read the fixed-image.  Given a 
single image is read using this class, it would not need a method like 
"ReverseOrderOn".  However, this may be the reason for the resulting 
"flipped" volume orientation.

Is there an inherent DICOM characteristic or tag in the DICOM 
necessitating the need to call the "ReverseOrderOn" method?

My immediate solution to this problem is to read the DICOM tag 
"Modality" (0008, 0060), and depending on the type of data-set being 
used, call the "ReverseOrderOn" method when constructing the volume.  
This seems like a band-aid solution - therefore this posting.  If there 
is a more correct approach, I would certainly like to use it.


Suggestions / comment are greatly welcomed!


Thanks!

Michael.

Robarts Research
London, ON
Canada