Registering complex-valued volumetric images

I have to MRI raw data images stacks, that is 3D-arrays of complex numbers. I'd like to align them through an affinity transformation like I would with imregtform, but that works only with grayscale images. I would need an additional parameter in my transformation matrix that accounts for a phase shift between the image stacks. Is there a good way of doing this with existing functions, or do I need to write something from scratch? Thanks!