MYELOGRAPHY and CNS Exams using MRI & CT Spring 2011.

MYELOGRAPHY and

CNS Exams using MRI & CT

Spring 2011

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

Why is Subarachnoid space so valuable?

– Wide space between arachnoid and pia mater• __________________________________• __________________________________• __________________________________• __________________________________

CSF Information

• Total adult CSF volume is ________ ml– ________intracranial– ________spinal

• Adult opening pressure is normally _______cm fluid– __________ abnormal– Young adults slightly higher ____________

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

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

Myelography

• ______________________________________

OMNIPAQUE

ISOVUE

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

Puncture made at L2-L3 or L3-L4 space

Spinal needle injection

MYELOGRAM WITH CONTRAST

Room should be prepared by RT before patient arrival

1)________________________

2) _______________________

3) _______________________

4) _______________________

5) _______________________

FOOTBOARD

SHOULDERPADS

Hand grips

MYELOGRAM TRAY

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

Syringes and Spinal Needles

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

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

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

Prone & Lateral Flexion

• Prone– ____________________

• Lateral flexion is not commonly used– ____________________

____________________

Scout Images

• Cross table lateral – With grid– Closely collimated

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

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

Myelogram overview

Ventricles and Myelography

• Acute Extension of neck– Why?

• What happens if contrast enters ventricles?• ______________________________________

____________________________________

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

Post procedure: Myelography1) _______________________________________

2) _______________________________________

3)________________________________________

4)________________________________________

5)________________________________________

6)________________________________________

Possible Complications from Myelography

1)

2)

3)

4)

Clinically- what is the difference between an regular headache and a spinal

headache?

1)

2)

3)

More Severe Complications

• Nerve root damage• Meningitis• Epidural abscess• Contrast reaction (anaphylactic shock)• CSF leak• Hemorrhage

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

Blood Patch

1) Clot will occur over hole

2) ___________________

3) ___________________

4) ___________________

Myelogram radiographs

Myelograms Images

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

CTM

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

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

Contraindications to MRI

1)

2)

3)

Myelography Using MRI and Conventional methods

MYELOGRAM

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

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

MRI and Brain imaging

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

Not valuable for diagnosing:

• Osseous bone abnormalities of skull

• Intracerebral hematomas

• Subarachnoid Hemorrhage

– CT preferred for these 3 illnesses

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

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

Indications for Brain scans without Contrast media

• Dementia

• Craniocerebral trauma

• Hydrocephalus

• Acute infarcts

• Post evacuation follow up of hematomas

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

CT Brain imaging (cont)

• Coronal imaging

– Helpful in evaluation of• Pituitary gland• Sella turcica• Facial bones• Sinuses

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

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.

Surgery Applications of CT imaging

• Greatly assists surgeons in distinguishing neural compression by soft tissue from compression by bone

• Post-op– Useful in assessing outcome of surgical procedure

MRI vs. CT

• MRi superior to CT for imaging of posterior fossa– CT has artifacts from bone– MRI is free from bone artifacts

• MRI has inability to image calcified structures. CT is superior for calcifications

• MRI can detect cerebral infarction earlier than CT.

• Both modalities provide similar information on subacute and chronic strokes

Diskography and Nucleography

• Radiologic exam of individual intervertebral disks– 1)

– 2)

– 3)

– 4)

Diskograms

Lumbar Diskograms

Vertebroplasty

• Interventional radiology procedure to treat compression fractures or other pathologies in the vertebral bodies

• Used when _______ treatment does not work– Used when _______ pain does not improve over a

number of _____________________ of treatment

Percutaneous Vertebroplasty

• Done in specials or OR– 1)

– 2)

– 3)

– 4)

– 5)

Vertebroplasty under Fluoro

Post Vertebroplasty

Kyphoplasty Outline

Pre and Post Kyphoplasty radiographs

Complications of Vertebroplasty and Kyphoplasty

• Most common: _________________________

• Less common: _________________________– Death

Success of Vertebroplasty and Kyphoplasty

• Success is measured by___________________________________

• Can help reduce ___________ and restore________________________________

• With Kyphoplasty there is a 80-90% success rate

Vertebroplasty and Kyphoplasty clips

• http://www.unikron.com/tools/play/play_display.cgi?speed=hi&id=good_samaritan2

• http://www.or-live.com/StJoseph/1319/

Pain Management

1)

2)

3)

4)

Considerations of Pain Management Interventional Procedures

• Stop NSAID 3 days prior to procedures

• With Facet injections no pain relievers 4 hours prior to procedure

• Takes 3- 10 days for full results to manifest

• Done when conventional treatment has not helped

Epidural• Used to treat pain as a result of and injured disk affecting

spinal nerves– _________________________________________________________

• Done under fluoroscopy with PT awake– _________________________________________________________– _________________________________________________________– _________________________________________________________

• Complications– Most common:_______________________– ___________________________________– ___________________________________

Epidural1)

2)

3)

4)– Cortisone– Lidocaine

Epidural with Catheters

Facet Injections

• Indications:1)2)

• Causes of pain include:– ____________________

____________________

• Awake under fluoro1)

2)

• Complications1)2)3)4)

Facet Injections

1)

2)

3)

Side effects of Steroids

• Fluid retention

• Weight gain

• Mood swings

• Increase in blood pressure

• Usually temporary

Spinal Cord Stimulation

• Delivers low voltage electrical stimulation to the spinal cord– 1)– 2)

• Done in two stages– 1)– 2)

SCS Radiographs

Trial and Permanent Placement

• Done in OR– ________________________

________________________

• _______________________

• ______________________________________________

• If trial period helps:– ________________________

• Contains generator with battery (some are rechargeable)– Periodically battery is

replaced

• Others have transmitters & generators

Generators only vs. Generators with Transmitters

• SCS with generators inside the body must be replaced in OR– ____________________

– ____________________

• SCS with transmitters can also be one time use or rechargeable– ____________________

____________________

SCS With Generator and Transmitter

SCS Indications, Benefits & Risks

• Indications:– Chronic pain associated with:

• Neuropathic pain• Failed back surgery

syndrome• Arachnoiditis• Certain vascular disease

• Benefits1)

2)

3)

• Risks1)2)3)4)5)

Radiofrequency Neurolysis

• Uses high frequency radio waves to produce a heat lesion1)2)3)

• Done under fluoro in OR

Radiofrequency Neurolysis• Helps for_____ months

• ______of PT’s get relief

• Takes about_________ minutes

• Can be repeated if pain returns

Radiofrequency Neurolysis

• PT is__________________ and ______ sedated• Local anesthetic injected

– 1)– 2)

• Once PT confirms this , they are sedated more– 1)– 2)

RF Risks

• Infection

• Bleeding Blood vessel damage

• Soreness for a few days