MRI of Spinal Cord.pptx Veterinary's medicine Veterinary medicine Veterinary medicine

1. MRI OF SPINAL CORD

2. Basic Anatomy of Spinal Structures
• Dorsal and ventral support for the
intervertebral discs provided by
longitudinal ligaments of vertebral
column – dorsal longitudinal ligament,
ventral longitudinal ligament
• Additionally – intercapital ligaments,
yellow ligaments
• Cranial and caudal extremities of
spinal cord located respectively at
foramen magnum and conus
medullaris (caudal to L6 in small dog
breeds, cats; cranial to L6 in large dog
breeds)
• Widening of spinal cord at 6th-7th
cervical and 4th-5th lumbar vertebrae is
NORMAL
• Ratio between diameter of spinal cord
and diameter of vertebral canal higher
in chondrodystrophic breeds
• Intervertebral disc made of a

3. • 3 meningeal layers surround the spinal
cord – dura mater, arachnoid membrane,
pia mater
• Between the arachnoid and pia mater is
the subarachnoid space which contains
CSF
• Subdural space – between dura mater and
arachnoid
• Outside of the dura mater is the epidural
space which contains fat, fluid, internal
vertebral venous plexus
• Nerve roots exit the vertebral canal
through intervertebral foramina
• CSF is also found in the central canal of
the spinal cord, which is lined by
ependymal cells

4. NORMAL MRI SPINAL ANATOMY

5. Sagittal image of cranial cervical vertebral column
• Double-headed arrow: Spinal cord
• Arrowhead: Dens of the axis
• Arrow: Gray matter of spinal cord parenchyma
• Asterisk: CSF forms hypointense space
• Vertebral cortical bone appears as a
black shell
• Epidural and paraspinal fat –
hyperintense
• Spinal cord, nerve roots, bone
marrow isointense or slightly
hypointense compared with
intervertebral disc
• Gray matter of spinal cord can
occasionally form a hyperintense line
in the center of the cord

6. Transverse T1W (a) and T2W (b) images – lumbar intervertebral disc
• Asterisk (a) – Subarachnoid space (CSF) forms hypointense space
around cord
• Asterisk (b) – Subarachnoid space hyperintense
• Arrowheads (a and b) – Epidural fat – hyperintense

7. Transverse T1W and T2W images of cervical spine
• Arrows: Butterfly-shaped hyperintense gray matter compared with
hypointense white matter
• Dashed arrows: CSF in subarachnoid space hypointense on T1W and
hyperintense on T2W
• Arrowhead (b): Nucleus pulposus – mottled areas of low signal consistent

8. • Arrowhead: Internal venous plexus forms two rounded structures over
the vertebral body
• Dashed arrows: Internal venous plexus abaxially displaced
• Dotted arrows: Intervertebral veins
• Solid arrows: Articular process joints, with articular cartilage and
synovial fluid forms a hypointense line between dark vertebral cortical
bone margins

9. Transverse T1W and T2W images at the level of L5
• Arrowhead (b): Thecal sac (duramater and arachnoid) forms a
hypointense ring around conus medullaris (dotted arrows)
• Solid arrows: Nerve roots – hypointense small rounded structures
• Asterisks: Epidural fat hyperintense in both images

10. Sagittal T2W image of caudal
lumbar spine
• Arrowhead: Focal area of
hyperintense signal in the
cranial endplate of L5 –
indicative of normal red
hematopoietic bone marrow
conversion into yellow fatty
marrow
• Arrows: Nuclear clefts visible in
the nucleus pulposus of all
discs indicative of early
degenerative change

11. Parasagittal T2W image of cervical
spine
• Asterisks: corresponding articular
processes of two adjacent
cervical vertebrae
• Arrow: hyperintense synovial
fluid within articular process joint

12. Sagittal (a) and transverse (b) T2W images of lumbar spine in a dog
• Arrowheads: hyperintense structure formed in the middle of the vertebral
body by the basivertebral venous canal

13. Sagittal (a) and transverse (b) T2W images of cervical spine
• SC – Spinal cord
• NP – Hyperintense signal of normal nucleus pulposus
• Asterisks – Hypointense annulus fibrosus

14. Parasagittal T2W of thoracolumbar spine
• Arrowheads: rounded rib heads
• Arrows: ellipsoid lumbar transverse processes

15. Sagittal T2W image of thoracolumbar spine
• AO – Aorta
• Arrowhead – Celiac Artery
• Arrow – Cranial Mesenteric Artery

16. DEGENERATIVE DISC DISEASE AND DISC HERNIATION

17. Classification of Intervertebral Disc Disease

18. MRI Features of Disc Degeneration
• Early: Decreased T2 signal of nucleus pulposus, with or without a linear
hypointense signal parallel to the endplates called nuclear cleft
• Late: T2 signal intensity of disc decreases more and more, and width of disc
decreases
• Loss of continuity and integrity of annulus become apparent, ultimately disc
protrusion or extrusion may develop

19. Disc bulging Disc extrusion
Disc protrusion

20. Disc Extrusion
Sagittal T2W
Transverse T2W Transverse T1W
• Arrows: Markedly hypointense compressive material

21. Sagittal T2W – Lumbar Spine – L4-L5 Disc Extrusion
• L4-L5 disc space narrowed
• Hypointense disc material seen over mid body of L4
causing severe ventral spinal cord compression
• Arrow – disc material migrated cranially

22. Transverse fast spin echo T2W image over
body of L4 in dog with acute disc
herniation at L4-L5
• C – Spinal Cord
• Asterisk – Large amount of T2
heterogeneous extradural material
causing compression and displacement
of spinal cord

23. Spinal Cord Compression due to L5-L6 Disc Extrusion
T1W Pre-Contrast
Transverse T2W
T1W Post-Contrast
• Arrow: Hypointense and heterogeneous disc material causing marked left ventral cord
compression (moderate patchy enhancement post-contrast)

24. Beagle presented with cervical pain – Foraminal herniation of disc material
Sagittal T2W
Transverse T2W
C2-C3 intervertebral disc space
• Arrowhead – C2-C3 space is narrowed and hypointense and there is mild ventral
cord compression due to disc material extrusion
• Arrow – Irregular hypointense material in the ventral aspect of the left
intervertebral foramen

25. Dachshund presented for lameness in right pelvic limb – Lumbar Spine MRI
Sagittal T2W
Parasagittal T2W
Transverse T2W
• Arrowhead – The L5-L6 disc space is narrowed and
hypointense, but no cord compression is noticed
• Dashed arrow – Rounded hypointense structure seen in
right L5-L6 intervertebral foramen corresponding to
extruded disc material
• Solid arrow – Dorsolaterally extruded disc material

26. Acute Hydrated Nucleus Pulposus Extrusion Over C3-C4
• Arrows – Focal area of patchy T2 hyperintensity in spinal cord over affected disc space
• Arrowhead – C3-C4 disc – decreased volume and signal intensity of nucleus pulposus
• Dashed arrow – Small amount of non-compressive epidural material which is
hypointense to epidural fat

27. CERVICAL SPONDYLOMYELOPATHY

28. • CSM or Wobbler Syndrome is a disease of cervical vertebral column of large
breed dogs
• Characterized by dynamic and static compressions of cervical spinal cord,
nerve roots, or both, leading to variable degrees of neurologic deficits and
neck pain
• Common in Doberman Pinschers and Great Danes

29. Pathophysiology:
• Key static factor – vertebral canal stenosis
• Affects entire cervical spine
• Osseous (Great Danes) or disc-associated (Doberman Pinschers)
compressions
• Disc associated:
o Relative vertebral canal stenosis
o More pronounced torsion in caudal cervical vertebral region
o Protrusion of larger volume discs in caudal cervical spine
• Osseous:
o Absolute vertebral canal stenosis
o Vertebral malformation

30. Transverse T2W image at the level of
C7-T1

31. • Complete loss of T2 signal of all intervertebral discs
except for C3-C4 consistent with degeneration
• Mild ventral spinal cord compression at C5-C6

32. • Arrows – bilateral foraminal stenosis
• Lateral spinal cord compression
secondary to articular process joint
proliferation

34. References:
1. Diagnostic MRI in Dogs and Cats (Wilfried Mai)
2. Handbook of Small Animal MRI (Ian Elliott, Geoff Skerritt)
3. Practical Small Animal MRI (Patrick R. Gavin, Rodney S. Bagley)