Acute Transverse Myelitis or GBS?

  How do neurologists distinguish between the symptoms/test results of acute transverse myelitis as opposed to the acute onst of GBS?  What "pictures" should the MRI's, spinal tap or EMG show to distinguish between the two?  What about the presence or absence of deep tendon reflexes or Babinsky sign?  Can GBS spinal tap results also have high cell count as well as high protein count? What if parasthesias were in the back, not the legs? I really appreciate all the info this BB has provided, although often it has led to other questions?  The doctors who respond have been great!
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In comparing the two conditions it may be less obvious in the early stages
of Transverse myelitis but as the process evolves things become more clear cut.
Reflexes : Brisk in transverse myelitis, absent in GBS
Babinski : Upgoing toes in Myelitis, downgoing in GBS
MRI cord : May show inflammation in myelitis, normal on GBS
CSF protein : Very high in GBS, mild/moderate elevation in Myelitis
Cell count  : variable not a very reliable indicator, tends to be higher in myelitis
EMg