[IGSTK-Users] Multiframe DICOM

[Satish]

Hi Ziv,

 

Thanks for elaborating on this. Yes it is a xa projection (axial slices
from what I can see).

I followed your (and Louis and other) suggestion (added xa image reader
objects) and have created a new igstk app in visual studio 9.0 on the
lines of needle-biopsy app, and is now able

to load the image file and display in the 4 quadrants, only if they are
loaded from a folder with .dcm image series. Had to split the large
DICOM file into its frames as .dcm into 

a folder to do this. It was not loading if I tried with one single large
file. 

 

I am by no means a expert on igstk, and might me missing many things
here. Anyway, the goal is to load large xa modality files and perform
segmentation based on our custom

algorithms which intend to use ITK for this. Registration and
visualization will follow. 

 

First question is will igstk allow us to access full potential of ITK
for segmentation, or we have to rely on what igstk provides. Also in
cases like the hack you mentioned, how do we

Integrate ITK pipe into igstk if we have to fall back on ITK to
load/process large DICOM files through igstk.

 

Also along the roadmap is to be able to grab the DICOM fluoro directly
from the c-arm, and superimpose 3d data over 2d-fluoro, question is will
igstk support this kind of approach.

Again I'm not an expert on igstk (I'm .net architect), so are we on
right track?

 

Cheers

-          satish

 

 

From: Ziv Yaniv [mailto:zivy at isis.georgetown.edu] 
Sent: Tuesday, January 04, 2011 5:11 PM
To: igstk-users at public.kitware.com; Satish
Subject: Re: [IGSTK-Users] Multiframe DICOM

 

Hi Satish,

Multi-frame DICOM is a bit too generic. Are you talking about a set of
slices comprising a volume that are contained in a single file instead
of multiple single slice files? Perhaps these are the XA projection
images which you were previously asking about? 

Also, if the DICOM tag for modality  is not CT the igstkCTImageReader
will refuse to read it. For example a set of axial slices from cone-beam
CT that have an XA modality tag, even though they are equivalent to a
CT. This is intentional. 
If we expect a CT we don't want to allow the user to load an MR without
the developer knowing about this.

I suggest that you first try to read the data using an igstk reader. If
non of them work then try reading using an ITK reader. Once you
establish which pixel type and other parameters work within ITK you can
implement an igstk reader which will only accept that type. This ensures
that you only read the expected data type (important if you want preset
window and level values to work as expected, etc.).

If we are still talking about the XA projection images, then the
following "hack" in ITK may work for you; load the image set as a single
3D image.

This may not work if the movie is too long as ITK tries to load the
whole thing. 

If it does work you need to BE CAREFUL with your usage of this "volume".
The ITK concept of an image associates a pixel spacing with each
dimension, thus your 3D volume will most likely have a pixel dimension
of 1 in each direction. In the image, x-y, plane this is fine, but your
"z" plane will be time which should not be treated in the same way as
space "x-y".
When/if you apply ITK filters to this type of data you will most likely
need to apply them in a "slice by slice" manner. 


                    hope this helps
                                       Ziv


On 1/4/2011 11:21 AM, Satish wrote: 

Hi all,

Is it possible to read a multi-frame DICOM file (approx 250MB) with the
igstkCTImageReader ?

Or do we have to split it into multiple .dcm files and read...if so how
do we split?

 

Regards

Satish Kumar B.G

 

Technical Architect

COMPUSOL

 

 
 
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-- 
Ziv Yaniv, PhD., Research Assistant Professor
Imaging Science and Information Systems (ISIS) Center
Department of Radiology
Georgetown University Medical Center
2115 Wisconsin Avenue, Suite 603
Washington, DC, 20007,
 
Phone: +1-202-6877286
Fax: +1-202-784-3479
email: zivy at isis.georgetown.edu
web: http://isiswiki.georgetown.edu/zivy/
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