[vtkusers] image data to structured grid in spherical coords

[Marty Humperdink]

Hello. 

I have some 3D ultrasound data stored as a header-less raw file. The data is in spherical coordinates which I know (roughly) from a separate source. 

I'd like to resample the 3DUS data into a Cartesian grid.

I've been using vtkImageReader2 to load the data from the raw file giving me vtkImageData. 
I believe I need to create a vtkStructuredGrid from this image data and apply the 
Spherical coordinate geometry (do I just do this to the points? can I preserve the topology of the imageData?). Then I think I could use vtkProbeFilter to resample the 
structured grid with a new vtkImageData object.

Could someone please suggest a method to transform the vtkImageData object into a structured grid with the spherical 
coordinate geometry? I have been trying various approaches with little overall success. 

I would greatly appreciate any feedback or suggestions.

MH