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) _______________________ FOOT BOARD SHOULDER PADS 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: Myelography 1)_______________________________________ 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 degrees to OML – Allows lowest slice to provide an image of both the upper cervical, foramen magnum, and roof of orbit 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 lay.cgi?speed=hi&id=good_samaritan2 lay.cgi?speed=hi&id=good_samaritan2

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 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:_______________________ – ___________________________________

Epidural 1) 2) 3) 4) – Cortisone – Lidocaine

Epidural with Catheters

Facet Injections Indications: 1) 2) Causes of pain include: – ____________________ ____________________ Awake under fluoro 1) 2) Complications 1) 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 Benefits 1) 2) 3) Risks 1) 2) 3) 4) 5)

Radiofrequency Neurolysis Uses high frequency radio waves to produce a heat lesion 1) 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