1. Myelography
9/30/10 online ed.

2. Central nervous system
2 basic parts- What are they?
Brain
Spinal Cord

3. The Brain Composed of outer portion of gray matter called? Cortex
Inner portion- white matter

4. The Brain Forebrain-largest part of brain know as? Cerebrum Midbrain
Divided into lobes and lobules by sulci
Midbrain
Connects cerebrum to
pons and cerebellum

5. Hindbrain
Cerebellum-largest part of hind brain
Pons
Medulla oblongata

6. Prefrontal Cortex
Area “scrambled” during lobotomy

7. Spinal Cord Continuous with medulla oblongata
Extends from brain to approximately L2
Connected to 31 pairs of spinal nerves

8. The Meninges Layered coverings of brain and spinal cord
Pia mater- inner sheath
Highly vascular
Arachnoid- central sheath
Separated from pia mater by subarachnoid space
Dura mater- outer sheath
Outermost, protective layer

9. Ventricles- 4 fluid-filled cavities within the brain
What is that fluid?
Cerebral spinal fluid (CSF)
Two upper pair are identical, known as left and right lateral ventricals
3rd Ventrical- just inferior to body of lateral ventricals
4th Ventrical located in hindbrain
All ventricles communicate with each other through special connecting channels known as interventricular foramina

10. R and L Lateral Ventricles
located in forebrain
Body
anterior horn
posterior horn
inferior horn

11. Ventricles cont’d Lateral ventricles 3rd ventricle 4th ventricle
Superior Aspect

12. Pneumoencephalography
Introduced in 1919
Performed extensively throughout late 20th century
Cerebrospinal fluid -a small amount drained from around brain and replaced with air, oxygen, or helium as contrast to allow the structure of brain to show up more clearly on an X-ray
Derived from cerebral ventriculography- air is injected through holes drilled in skull
Pt turned upside down in special chair that can rotate vertically 360 degrees to get air to fill ventricals

13. Pneumoencephalography cont’d
Extremely painful, very dangerous
Test was generally not well tolerated by pts-
headaches and severe vomiting common side effects
Replacement of spinal fluid was by natural generation- took as long as 2-3 months
MRI and CT have largely replaced Pneumoencephalography.

14. Myelography- Radiographic exam of spinal cord
X-ray examination performed by radiologist to detect abnormalities of the spine, spinal cord, or surrounding structures
Contrast material is injected into the fluid-filled space around spinal cord
X-rays are taken

15. Myelogram cont’d Air used for early myelograms
Injected via lumbar puncture
In 1922, iodized poppy seed oil was used
Accidentally discovered with no apparent side effects
Nonionic, water-soluble compounds now used
Demonstrates a low neurotoxicity
CT and MRI now chiefly used to image nervous system

16. Myelography Injections can be given at:
Cistern (below occipital bone -can be hazardous because the needle is inserted close to brain stem)
Cervical spine
Thoracic spine
lumbar region (most common)
Injection is in subarachnoid space –which is?
(space between arachnoid and pia mater)

17. Myelography Indications
Intraspinal abnormalities
Nerve root abnormalities
Disk prolapse (slipped disk), herniation
Spondylosis- degenerative arthritis of spinal vertebra and related tissue
Spondylolisthesis
Spinal stenosis (spinal canal narrows and compresses spinal cord and nerves)
Tumors
Metastases

18. Myelography Contraindications
Central aneurysms-(balloon-like bulge in an artery caused by weakening of artery wall)
Arterio-venous malformations
lumbar puncture within one week
Previous reaction to contrast

19. Preliminary Radiographs
Purpose
Determine accurate bony anatomy
To exclude pathologies that wouldn’t need myelography
Distinguish congenital abnormalities
For correlation with myelography, MRI and CT images when reporting

20. Preliminary Radiographs
Lateral
Both anterior oblique views to demonstrate pars interarticularis (neck of Scotty dog)
Lateral L5-S1

21. Contrast Media Iohexol – Nonionic, water-soluble contrast
Iotrolan (Isovist) – More recent contrast agent
Less toxic than Iohexol

22. Procedure Sequence Prepare room, sterile trays, and contrast
Pt placed prone on table
Area to be punctured is cleaned and prepped with sterile towels
Local anesthetic injected in area of puncture

23. Procedure Sequence (cont’d)
Lumbar puncture needle inserted under fluoroscopic guidance until fluid appears
CSF may be taken for analysis

24. Procedure Sequence (cont’d)
Contrast material injected
Flow monitored fluoroscopically
Pt. tilted into trendelenberg and reverse-trendelenberg to control flow of contrast during spot films Overheads

25. Radiographs taken during exam:
Generally, cross table lateral and PA
Why not routine views?
Pt has needle in spine
Don’t want to change contrast position by rotating pt

26. Lumbar Myelogram PA
Lateral

27. Myelography accuracy rate
When compared with surgical findings:
MRI – 96%
Myelography – 81%
CT – 57%
CT and Myelography together - 84%

28. Cervical
Myelogram

29. Set-Up for Lateral Cervical Film

30. Cervical Radiographs Overheads PA PA Oblique projections
Cross-table lateral films

31. Alternative Radiographs
Lateral flexion/extension
Demonstrates:
Stenosis
spinal instablility
deg. of movement of disk protrusion

32. Patient Care Concerns
Maintain head in acute extension during examination!
Bedrest 8 – 24 hours after procedure with head elevated
Encourage hydration

33. Possible Post-Procedure Complications
Headache
Hypotension- which is?
Low blood pressure
Convulsions
Confusion/hallucinations!

34. Advanced Imaging Techniques

35. Diskography Radiographic exam of intervertebral disks
Contrast is injected directly into disk
Determines disk morphology
Reproduces pain caused by disk disease itself

36. Diskogram Films

37. CT Brain Scan Very accurate diagnosis of acute intracranial injuries
Often 1st to evaluate head and spine trauma
Very accurate diagnosis of acute intracranial injuries
Contusions
Hemorrhage
Fracture evaluation

38. MRI (Magnetic Resonance Imaging)
In brain for assessing:
Middle and posterior cranial fossa abnormalities
Acoustic neuromas
Pituitary tumors
Primary and metastatic neoplasms
Hydrocephalus
AVMs
Brain atrophy

39. MRI In spine-for assessing: Demyelinating disease-
(any condition resulting in damage to the protective covering (myelin sheath) that surrounds nerves in brain and spinal cord)
Spinal cord compression
Paraspinal masses
Postradiation therapy changes in spinal cord tumors
Metastatic disease
Herniated disks
Congenital anomalies