MYELOGRAPHY and CNS Exams using MRI & CT

1. MYELOGRAPHY and CNS Exams using MRI & CT Spring 2011

2. Meninges • Membranes that enclose the brain and spinal cord • Dura Mater- outer layer • Arachnoid = middle layer • Pia mater = innermost layer • Subarachnoid space = wide space between arachnoid and pia mater

3. Why is Subarachnoid space so valuable? • Wide space between arachnoid and pia mater • __________________________________ • __________________________________ • __________________________________ • __________________________________

4. CSF Information • Total adult CSF volume is ________ ml • ________intracranial • ________spinal • Adult opening pressure is normally _______cm fluid • __________ abnormal • Young adults slightly higher ____________

5. Spinal Cord Diameter • AP diameter is _______mm through C7 • C7 to conus medullaris is ________mm • At conus it is __________________mm • Cord size is considered abnormal if it is over __________mm or under _________mm

6. Myelography • General term applied to the radiologic examination of the CNS structures situated in the vertebral canal • Requires contrast introduction into the subarachnoid space by spinal puncture • Puncture made at L2-L3 or L3-L4 space • May also be introduced into cisterna magna at C1 and occipital bone

7. Myelography • ______________________________________ OMNIPAQUE ISOVUE

8. Contrast Precautions • Verify it is the correct contrast • Non-ionic iodinated contrast • Omnipaque or Isovue • Correct concentration • 180 and 300 common • Check ______________________ • Keep contrast vial in room until procedure is complete

9. Puncture made at L2-L3 or L3-L4 space

10. Spinal needle injection

11. MYELOGRAM WITH CONTRAST

12. Room should be prepared by RT before patient arrival 1)________________________ 2) _______________________ 3) _______________________ 4) _______________________ 5) _______________________ FOOT BOARD SHOULDER PADS Hand grips

13. MYELOGRAM TRAY

14. Additional items • Blankets • Sterile towels • Sodium bicarbonate (if not in tray) • Non-ionic iodinated contrast media • Sterile gloves for DR • Shields for PT, DR, anyone else in room, and yourself • Varying sizes of spinal needles and needles • Extra syringes and tubing • Cleaning liquid

15. Syringes and Spinal Needles

16. PRE- Procedure :Myelography • Premedication rarely needed • Patient should be well hydrated • Check orders, obtain history, labs results (if necessary), and previous exams • Informed consent: • Risks, benefits alternatives • Procedural details, including table movement and sensations should be explained, and get pt into a gown

17. Contraindications and Considerations • PT < 15.0 seconds • Preferable to reschedule exam if below 15 • Platelets >100,000 • If below 50,000 a platelet transfusion may be indicated before procedure • Heparin stopped 4 hours before • Can be restarted 2 hrs after procedure • Usually given as IP • Coumadin stopped 3-4 days before • Usually OP • Labs usually indicated

18. Radiation Safety • Have shields • Question • LMP • Possibility of pregnancy • Use cardinal rules • ________________ • ________________ • ________________ • ALARA • Use pulse if possible • Save the last image on screen when possible

19. Prone & Lateral Flexion • Prone • ____________________ • Lateral flexion is not commonly used • ________________________________________

20. Scout Images • Cross table lateral • With grid • Closely collimated

21. Myelography • Local anesthesia given at puncture site • ______________________________ • Spinal needle inserted • __________________________________ • Labs • _________________________________ • Contrast injected and needle removed • _______________________ ml • The use of gravity • ________________________________ • Spot images taken as needed

22. Spot Films • Central ray vertical or horizontal using CR or film screen cassettes • Images are taken at • Site of blockage • Level of distortion • If conus medullaris is area of concern: • Lay pt supine • Central ray at T12- L1 • Use 10x12 cassette and collimate tightly

23. Myelogram overview

24. Ventricles and Myelography • Acute Extension of neck • Why? • What happens if contrast enters ventricles? • __________________________________________________________________________

25. Myelography • Usually performed as outpatient basis • Common for CT myelography (CTM) to be used with conventional Myelogram • MRI often used instead • Myelography and CTM still used for patients with contraindications for MRI • Pacemakers and metal fusion rods

26. Post procedure: Myelography • _______________________________________ • _______________________________________ 3)________________________________________ 4)________________________________________ 5)________________________________________ 6)________________________________________

27. Possible Complications from Myelography 1) 2) 3) 4)

28. Clinically- what is the difference between an regular headache and a spinal headache? 1) 2) 3)

29. More Severe Complications • Nerve root damage • Meningitis • Epidural abscess • Contrast reaction (anaphylactic shock) • CSF leak • Hemorrhage

30. Treatment for Spinal Headache • Initial treatment 1) 2) 3) 4) • Persistent headache • Fever occurs • ___________________ • May be indicative of ___________________ • ___________________ • Beyond 48 hrs • No Fever • 24 hrs if severe • No fever

31. Blood Patch • Clot will occur over hole • ___________________ • ___________________ • ___________________

32. Myelogram radiographs

33. Myelograms Images

34. CTM • Performed after _____________________________ • Can be performed at _____ level of vertebral column • Multiple slices taken _________________________ • Gantry is ________________________________________ • Windowing allows for density and contrast changes • Can obtain images with _______ amounts of contrast • Can be done _______________ hours after initial injection

35. CTM

36. MRI of Spinal Cord and CSF flow • Non-invasive • Provides anatomic detail of brain, spinal cord, intravertebral disc spaces, and CSF within subarachnoid space • Does not require intrathecal injection • Does not have bone artifacts

37. MRI basics • T1 & T2 images can be taken • Head coil for brain • Body coil and surface coil form spine • IV contrast can be used to enhance tumor • Gadolinium

38. Contraindications to MRI 1) 2) 3)

39. Myelography Using MRI and Conventional methods MYELOGRAM

40. Preference of MRI • MRI is the preferred modality for middle and posterior cranial fossa of brain. • In CT these structures are obscured by bone artifacts • Spinal cord • Allows direct visualization of spinal cord, nerve roots, and surrounding CSF • Can be done in various planes • Aid in diagnosis and treatment of neurodisorders

41. Usefulness of MRI • Assessing demyelinating disease • Such as MS • Spinal cord compression • Postradiation therapy changes of spinal cord tumors • Herniated disks • Congenital abnormalities of vertebral column • Metastatic disease • Paraspinal masses

42. MRI and Brain imaging • Middle and posterior fossa abnormalities • Acoustic neuromas • Pituitary Tumors • Primary and metastatic neoplasms • Hydrocephalus • AVM’s • Brain atrophy

43. Not valuable for diagnosing: • Osseous bone abnormalities of skull • Intracerebral hematomas • Subarachnoid Hemorrhage • CT preferred for these 3 illnesses

44. CT of Brain basics • Useful for demonstrating size, location and configuration of mass lesions and surrounding edema • Assessing cerebral ventricle or cortical sulcus enlargement • Shifting of midline structures caused by mass lesions, cerebral edema, or hematoma

45. Indications for Pre and Post contrast Imaging using CT • Suspected Neoplasms • Suspected metastatic disease • Arteriovenous malformation (AVM) • Demyelinating disease (MS) • Seizure disorder • Bilateral isodense hematomas

46. Indications for Brain scans without Contrast media • Dementia • Craniocerebral trauma • Hydrocephalus • Acute infarcts • Post evacuation follow up of hematomas

47. CT Brain imaging • Most often Axial orientation • Gantry 20-25 degrees to OML • Allows lowest slice to provide an image of both the upper cervical, foramen magnum, and roof of orbit • 12-14 slices • 8-10 mm slices • 3-5 mm slices through post fossa • Depending of PT size • Slice thickness

48. CT Brain imaging (cont) • Coronal imaging • Helpful in evaluation of • Pituitary gland • Sella turcica • Facial bones • Sinuses

49. CT: Modality of choice • Modality of choice for the following” • Hematomas • Suspected aneurysms • Ischemic or hemorrhagic strokes • Acute infarcts • Used as initial diagnostic modality for: • Craniocerebral trauma

50. CT of Spine • Useful in diagnosis of vertebral column hemangiomas and lumbar spine stenosis • Often used post-trauma to assess Axis and Atlas fractures and for better demonstration of C7-T1 • Clearly demonstrates size, number and locations of fracture fragments of C, T and L spine.