The myelogram shows the CSF and bones and not
much else. (Showing the fluid indirectly shows
the tissues protruding into it.) I think the
only advantages are: speedy, cheap, dynamic
(can show fast movement. why? I dunno), and
does not require being so motionless so long.
Myelograms can be two-dimensional or CAT
generations of three dimensional representations.
The MRI shows the CAT equivalent, but the process
and its capabilities are quite different. The MRI
process detects the differences between soft tissues
(and other tissues also). An Xray process (e.g.
myelogram) shows meat as an almost homogeneous
ghost. The MRI shows the blood vessels and tendons
within the meat. If you don't mind being squeezed
into a "steel drum target on a machine gun range",
the MRI is superb.
However, you cannot have an MRI if there is any
steel/iron/nickel in or on your body. A shrapnel
victim couldn't be put in an MRI machine, ever.
Alton, who goes to sleep in the MRI machine