MYELOGRAPHY and

CNS Exams using MRI & CT

Spring 2009(DRAFT)

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

Subarachnoid space Wide space between arachnoid and pia mater

Filled with CSF Bathes brain & spinal cord with nutrients Cushions against shocks and blows Where contrast is injected for myelograms

CSF Information Total adult CSF volume is 150 ml

50% intracranial 50% spinal

Adult opening pressure is normally 7-15 cm fluid >18 abnormal Young adults slightly higher <18-20

Spinal Cord Diameter AP diameter is 7mm through C7 C7 to conus medullaris is 6mm At conus it is 7mm

Cord size is considered abnormal if it is over 8mm or under 6mm

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

Contrast is generally water-soluble, nonionic, iodinated medium

OMNIPAQUE

ISOVUE

Contrast Precautions Verify it is the correct contrast

Non-ionic iodinated contrast Omnipaque or Isovue

Correct concentration 180 and 300 common

Check expiration date

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

Table and equipment cleaned

Footboard and shoulder supports attached

Radiographic equipment checked

Image intensifier locked to prevent accidental contact with sterile field or spinal needle

Tray setup

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

Syringes

Spinal Needles(covered)

More Spinal Needles (uncovered)

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 for PT’s, DR and yourself

Question LMP and the possibility of being pregnant

Use cardinal rules Time Distance Shielding

ALARA Use pulse if possible Save the last image on screen when possible

Prone & Lateral Flexion Prone

Pillow under abdomen for flexion of spine

Lateral flexion is not commonly used Widens interspace for

easier introduction of needle

Scout Images

Cross table lateral With grid Closely collimated

Myelography

Local anesthesia given at puncture site Lidocaine and sodium bicarbonate

Spinal needle inserted (pressure obtained)

CSF usually withdrawn and sent to laboratory

Contrast injected and needle removed 9-12 ml

Table angle and gravity used to move contrast under fluoroscopy

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

Myelography

If contrast is moved into cervical area, head is positioned in acute extension to prevent contrast from entering ventricular system

Acute extension compresses cisterna magna and is the only position that will prevent contrast from entering 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: Myelography Monitoring required

Head and shoulders elevated 30 to 45 degrees

Bed rest for several hours

Fluid encouraged

Puncture site checked before release

Possible Complications from Myelography Vomiting

Vertigo

Neck Pain

Spinal Headache

Due to loss of CSF during puncture

Increased severity upright

Decreased pain when recumbent.

More Severe Complications

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

Treatment for Spinal Headache Initial treatment

Tylenol

Horizontal position

Forced fluids

Caffeine

Persistent headache If a fever occurs,

contact MD May be indicative of

meningitis

Beyond 48 hrs w/o fever (24 hrs if severe) Blood patch

Blood Patch Sterily injecting a small

amount of patient’s blood into the epidural space Clot will occur over hole Usually will stop

headache immediately 1st patch is 70% effective 2nd patch is 95% effective

Myelogram radiographs

Myelograms Images

CTM

Performed after intrathecal injection

Can be performed at any level of vertebral column

Multiple slices taken (1.5 – 3mm) Gantry is tilted

Windowing allows for density and contrast changes

Can obtain images with small amounts of contrast Can be done 4 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 Pacemakers Ferromagnetic aneurysm clips Metallic spinal fusion rods

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 Small amount of water soluble iodinated contrast

injected into center of disk double needle entry Pt’s given local anesthetic

So pt is alert and communicate with DR about pain when needle and contrast are inserted

Used to investigate disk lesions Ruptured nucleus pulpous

Has been largely replaced by CTM and MRI

Diskograms

Lumbar Diskograms

Vertebroplasty Interventional radiology procedure to treat

compression fractures or other pathologies in the vertebral bodies

Used when conservative treatment does not work

Used when severe pain does not improve over a number of weeks of treatment

Percutaneous Vertebroplasty Done in specials or OR Trocar needle is advanced through pedicle into the

vertebral body under fluoro Non-ionic contrast media is used to confirm needle

placement Bone cement ( polymethyl methacrylate) is injected

into vertebral body using fluoro AP & LAT images taken post procedure

CT sometimes done as well

Vertebroplasty under Fluoro

Post Vertebroplasty

Percutaneous Kyphoplasty Trocar needle advanced

Through pedicle, avoiding spinal canal Biopsies can be taken Balloon catheter used to expand the compressed

vertebral body to near its original height before injection of bone cement

Trocar needle is considered the “working cannula”

Kyphoplasty Outline

Pre and Post Kyphoplasty radiographs

Kyphoplasty Short clip http://images.google.com/imgres?imgurl=http://

www.beverlyhillsspinesurgery.com/images/icon-video-kyphoplasty.jpg&imgrefurl=http://www.beverlyhillsspinesurgery.com/spine-surgery-lumbar-los-angeles.htm&usg=__Ev4umMv-foN7fMgacwWnVMuVF9A=&h=121&w=146&sz=6&hl=en&start=30&tbnid=B96VZbmx2Ojy4M:&tbnh=79&tbnw=95&prev=/images%3Fq%3Dkyphoplasty%26start%3D20%26gbv%3D2%26ndsp%3D20%26hl%3Den%26sa%3DN

Complications of Vertebroplasty and Kyphoplasty Most common: leakage of cement

Less common: pulmonary embolism Death

Success of Vertebroplasty and Kyphoplasty Success is measured by the pt’s pain

reduction and quality of life improvement

Can help reduce hunchback and restore normal curvature

With Kyphoplasty there is a 80-90% success rate

Vertebroplasty and Kyphoplasty clips http://www.unikron.com/tools/play/play_displ

ay.cgi?speed=hi&id=good_samaritan2

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

Pain Management Epidural Injection

Facet Injection

Spinal Cord stimulation

Radiofrequency Neurolysis

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 Decreased inflammation & swelling

Done under fluoroscopy with PT awake Takes 10- 15 minutes Recovery short Sterile procedure

Complications Spinal headache (most common Infection Epidural Hematoma

Epidural Can be done at any

level of the spine Place a needle (often

with catheter) into epidural space

Small amount of contrast injected to verify placement

Corticosteroid & anesthetic injected ( Cortisone Lidocaine

Epidural with Catheters

Facet Injections

Indications: Diagnosis Therapy

Causes of pain include: Inflammation, swelling,

or arthritis

Awake under fluoro Takes 20-40 minutes Sterile procedure

Complications Pain at site Bleeding Infection Increase in pain

Facet Injections Inject needle into facet

joint

Inject contrast to verify needle placement

Inject lidocaine or bupivivaine (anesthetic) & corticsteroid (anti-inflammatory)

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 Delivered through 1-2 wires which are carefully

placed in epidural space Electrical signals replace sensation of pain with a

tingling sensation Done in two stages

Trial Permanent placement

SCS Radiographs

Trial and Permanent Placement Done in OR

Local anesthetic & intravenous sedation

Wires placed in epidural space

PT goes home with wires in place for 1 week to test and see if it helps

If trial period helps permanent generator is placed under skin in OR

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 Some are one time use Those that are

rechargeable allow for more time in between battery replacement

SCS with transmitters can also be one time use or rechargeable PT can adjust settings

according to different programs Set by DR according to

PT’s pain patterns

SCS With Generator and Transmitter

SCS Indications, Benefits & Risks

Indications: Chronic pain associated

with: Neuropathic pain Failed back surgery

syndrome Arachnoiditis Certain vascular disease

Benefits Reduces rather than

eliminates pain Reduces pain by 50% Reduces narcotic use

Risks Infection & bleeding Paint at insertion site Nerve injury Dural puncture or tear Migration or breakage of

wire

Radiofrequency Neurolysis Uses high frequency radio waves to produce a

heat lesion Lesion ablates or inactivates nerves responsible

for transmitting pain Usually done in L and C spine Pain can be caused from whiplash or arthritis

Done under fluoro in OR

Radiofrequency Neurolysis Helps for 6-24 months

70% of PT’s get relief

Takes about 45-60 minutes

Can be repeated if pain returns

Radiofrequency Neurolysis PT is awake and mildly sedated Local anesthetic injected

Stimulation test is done to verify needle placement PT is questioned for tingling or buzzing feeling (as

when hitting your funny bone) Once PT confirms this , they are sedated more

Radio waves are transmitted ablating the nerve Muscles may spasm or “jump”

RF Risks Infection

Bleeding Blood vessel damage

Soreness for a few days