[Insight-users] Rigid Registration based on Region of Interest

[Wang Yanbo]

Hi, ALL

I understand that current registration scheme allows registration based on ROI.
Suppose I have a T2 weighted MRI as fixed image and T1 weighted MRI as moving image, I want to do a rigid registration only for a portion of T2 image, e.g. slice 10 to 20 of T2.
I can treat slice 10 to 20 as ROI of fixed image and do the registration with respect to the moving image. After the optimization procedure, I will get my final transformation parameters T.

Here comes my problems.

1. How can I visualize/get the corresponding region in the transformed moving image? If I use itkresampleimagefilter, I can only transform the whole moving image based on final transformation parameter T, but how to select the region (in the transformed moving image) corresponding to the ROI of fixed image?

2. In my work, fortunately the size of fixed image is exactly the same with the moving image. So, I guess that the corresponding region (in the transformed moving image) would be the region where slice 10 to 20 of T1 (moving image) are transformed to with parameter T and pre-defined center of rotation. Am I correct? I really don't know because the ITK registration scheme looks like a black box to me. 

3. Even if I am correct, what should I do if the fixed image and moving image have different sizes? 

I really hope someone could help me with this. 

Thank you in advance!

Kevin

------------------------------

Message: 3
Date: Thu, 21 Oct 2010 14:49:05 -0400
From: brian avants <stnava at gmail.com>
Subject: Re: [Insight-users] [Insight-registration] Registration of
        one sub-brain to full-brain
To: Torsten Rohlfing <torsten at synapse.sri.com>
Cc: insight-users at itk.org, insight-registration at itk.org
Message-ID:
        <AANLkTinGxfFxVNf2cUx528adT+XgUPyTYodWF8sie-rr at mail.gmail.com>
Content-Type: text/plain; charset=UTF-8

Hi Torsten

We've leaned towards the ability to provide explicit mask(s) to the
registration and metrics that allow you to focus the registration on
regions of interest.  It's an easy extension with potentially low
overhead to computation time, even in the dense case ... we should be
able to set up the image iterators to run only through the ROI and/or
overlap of ROIs, the latter meaning the overlap of the two masks you
passed in after transformation to a common space ... the latter part
is a little more interesting to think about in that the overlap of
ROIs will change at every iteration.   I think the optimized image
registration metrics in v4 allow something like this already.

B