I think I would disagree. A contrast MRI is a useful procedure if a patient has had a prior surgery AND further surgery is a potential issue because you want to differentiate between recurrent disc herniation or other pathology like post-surgical adhesions and scar tissue. Gadolinium (contrast) will help with differentiation.

The key technical difference is that a CT (better for bony lesions) myelogram will "indirectly" show a disc herniation, tumor or other space occupying lesion by virtue of a filling defect where an MRI (better for soft-tissue lesions) with or without contrast will "directly" show a disc herniation, tumor or infection with much greater clarity and resolution than CT or CT myelogram.

There is nothing in the Mayo link that expressly prefers myelograms over MRI's for space occupying lesions or the use of contrast for that matter. Depending upon what the clinician is looking for, it is very unlikely, most of the time, that a CT myelogram will show more than an MRI, with or without contrast. While kejbrew had a good outcome with myeolgram for their fusion, I had a C5-6 fusion with only MRI, no contrast, both of which are the "standard of care" for surgical disc herniation or most compressive disorders and also had a good outcome. In almost all applications, CT myelogram just simply isn't necessary, is risky and most of the time not ordered (for good reasons!). It does have isolated indications though.