Hemiparesis in a Pekingese dog, myelogram interpretation

An 8 years old , male, 6,4 kg (overweight), Pekinese was presented because of inability to bare weight on the right front and hind limb. The owner reported that the problem started one month ago with less severe presentation - occasional stumbling and knuckling on the right front leg. There was also occasional painful vocalization with  change in the body posture. Gradually, the condition deteriorated to a non-ambulatory status for the last 4 days. No response to NSAIDs and steroids, prescribed by the referring vet, was found.

Clinical exam:

During the neurological examination we found:

• serious proprioceptive deficits with both right limbs,
• the muscle tone of the hind limb provided some weight baring, but such was missing in right front leg; the same leg`s exam revealed decreased withdraw and extensors reflexes and mild muscle atrophy;
• normal reflexes in the right hind leg.
• the neurological status on the contralateral left limbs was normal, except decreased hopping reflex  in front one
• iIntact deep pain sensation was present in all four limbs
• no pain was elicited during neck manipulation and digital spinal compression
• mental status and cranial nerve reflexes were considered normal
• normal urine voiding was reported by the owner.

Considering the examination findings, c

ould you suggest the localization of  the lesion, before further diagnostic tests?

a)    cervical lesion, C1- C5, on the right
b)    C6 - T2, on the right
c)    C6 - T2, on the right

d)    thoracic lesionT3 - L3, on the  right
e)    central brain lesion, on the left
f)    right brachial nerve plexus

A plain radiograph of the cervical spine was done. The only abnormality noticed was moderate narrowing of C5-C6 disc space.

A cysternal myelography was performed, because a cervical compression was suspected.

The lateral myelograms revealed good contrast flow through the cervical area, but a ventral “double column” sign was visible at C5-C6. There was mild widening of the “myelon" at C5-C6 space on the ventrodorsal view and mild contrast thinning on the right.

What would be your interpretation in this case:

a)    Non-diagnostic myelogram, needs further imaging
b)    Extradural spinal neoplasia, at the right  C5 - C6 space
c)    Meningioma (dural) neoplasia at C5 - C6
d)    Intramedullary spinal neoplasia C5 - C6
e)    Extradural spinal compression, caused by IVDD- Hansen II, right lateralised disc protrusion C5-C6
f)    Fibrocartilagenous embolism lesion at the level of caudal cervical region