3D image viewer function

I've got 3D truecolor image that is form by 2D stack images. The images are interpolated followed by rendering. I've done that in 3 different channels (red, green, blue). After all the interpolation and rendering, i've combined all the channels back into 1 again using cat() function. And now i'm stuck on how to view that 3D image after the cat() function had been perofrmed???? anyone have any idea how it could be done??? i've tried using imagesc function but it doesn't work. Is there any other function that could allow me to view this 3D image???