Hi Phil,

The NIAK reader/writer really is meant for structural and functional MRI, not any MINC volume. The fourth dimension is expected to be time, and that plays a role at different places. I have worked at some point on a general purpose reader (that also does not have dependencies besides matlab). You may want to give it a try: 
https://github.com/SIMEXP/mominc

If the reader works, and this is of interest, I may try wrapping up the writer (it's very close to done). 

I hope this helps,

Pierre