Compare a pixel value between a VTK volume and ITK image

I have two vtkPolyData, one is a liver and the other a tumor. First of all, I select n points from the liver and then, I calculate the Hausdorff distance “” between this points and the tumor. (These vtkPolyDatas, “.vtp” files, were generated from a “.nrrd” image)

On the other hand, I read this nrrd image with ITK and I calculate the Maurer distance between the liver and the tumor.

So, the question is how can I compare the distances calculated with VTK and the distances calculated with ITK?

Can I get a pixel (i, j, k) in the ITK image and a pixel (x, y, z) in the VTK Volume and compare both…? The pixels size are different in images and volume?


Best regards.