Could I preserve an image resolution before and after Rigid registration?


I registered two head MRI images, a T2 and a CET1 image, using General Registration function with rigid.
The registration was succeeded, but the output image resolution has changed.
The image resolution of the CET1 image, which was the moving image, was 1×1×1.5 mm, however this has changed to 0.5×0.5×3 mm after rigid registration, which was corresponded with the image resolution of the fixed image.

Could I preserve an image resolution before and after Rigid registration?

Thank you,

The whole point of the image registration is to resample the moving image into the reference image’s domain. If your moving image has a lower resolution, and your reference has higher, your moving image will be matched to your reference’s one.

Perhaps you can reduce the resolution in your reference to match that of moving image prior to registration, and then try to register.

Or you take the resultant output image and use the ResampleScalarImage to bring to whatever voxel spacing you want.

Thank you for your reply.

I misunderstood the point of image registration.

Actually, I often used Amira, an image processing soft from Thermo Fisher.
Amira keeps a resolution before and after an image registration.

Is Amira an excption?

I can’t say how Amira does it, but if the reference image has a different spacing that the moving image and after registration the resultant image still preserves original image spacing, yes, I would say it is different than the image registration frameworks that I am familiar with. At least for deformable ones.

With rigid, you can choose to output a transform (as oppose to a new image), and then apply that affine transform to the original moving image. That shouldn’t change the image resolution.

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I really appreciate for your help!!