MRI SPINE /KNEE

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MRI SPINE /KNEE

• DR, P S H HETTIARACHCHI
• CONSULTANT RADIOLOGIST
• ASIRI SURGICAL HOSPITAL
• COLOMBO 5

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TISSUE COLOURS

• Water and pathology
• White on T2,
• dark on T1.
• Pathology stays white on FLAIR, water doesn't

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TISSUE COLOURS

• Fat
• white on T1 and T2
• dark on STIR and out of phase

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TISSUE COLOURS

• Hematoma varying with time

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TISSUE COLOURS

• Bone Marrow normally fatty
• white on T1
• White on T2
• replaced with edema or other pathology
• (dark on T1)
• Bone cortex, stones, and ligaments
• dark on everything
• Contusion is white

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TISSUE COLOURS

• Tumor hypervascular (neovascularity)
• white with gadolinium

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Approach to protocols

• T1 -MRI with dark fluid
• T2 -MRI with white water, inflammation
• cartilage is black
• STIR- T2 with dark fat
• Proton Density - cartilage is grey
• can suppress the fat
• Gadolinium enhanced - with fat suppressionT1
• bright blood
• dark fat
• Pathology bright

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Magnetic resonance imaging (MRI) of the spine

• A noninvasive procedure to evaluate different
  types of tissue, including
• the spinal cord
• intervertebral disks
• spaces between the vertebrae through which the
  nerves travel
• distinguish healthy tissue from diseased tissue.

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Magnetic resonance imaging (MRI) of the spine

• The cervical, thoracic and lumbar spine MRI
  should be scanned in individual sections.
• The scan protocol parameter like e.g. the field
  of view (FOV), slice thickness and matrix are
  usually different for cervical, thoracic and
  lumbar spine MRI, but the method is similar.

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Magnetic resonance imaging (MRI) of the spine

• The standard views in the basic spinal MRI scan
  to create detailed slices (cross sections) are
• sagittal T1 weighted and T2 weighted images over
  the whole body part
• transversal (e.g. multi angle oblique) over the
  region of interest with different pulse sequences
  according to the result of the sagittal slices.
• Additional views or different types of pulse
  sequences like fat suppression, fluid attenuation
  inversion recovery (FLAIR) or diffusion weighted
  imaging are created dependent on the indication.

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Indications

• Neurological deficit, evidence of radiculopathy,
  cauda equina compression
• Primary tumors or drop metastases
• Infection/inflammatory disease, multiple
  sclerosis
• Postoperative evaluation of lumbar spine disk
  vs. scar
• Evaluation of syrinx
• Localized back pain with no radiculopathy (leg
  pain)

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Contrast enhanced MRI

• Delineate infections, malignancies
• show a syrinx cavity
• support to differentiate the postoperative
  conditions. After surgery for disk disease,
  significant fibrosis can occur in the spine. This
  scarring can mimic residual disk herniation.
• Magnetic resonance myelography evaluates spinal
  stenosis and various intervertebral discs can be
  imaged with multi angle oblique techniques.

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• Cine series can be used to show true range of
  motion studies of parts of the spine.
• Advanced open MRI devices are developed to
  perform positional scans in the position of pain
  or symptom (e.g. Upright MRI formerly Stand-Up
  MRI).

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Contraindications

• MRI systems use strong magnetic fields that
  attract any ferromagnetic objects with enormous
  force.
• Caused by the potential risk of heating, produced
  from the radio frequency pulses during the MRI
  procedure, metallic objects like wires, foreign
  bodies and other implants needs to be checked for
  compatibility.
• High field MRI requires particular safety
  precautions.
• In addition, any device or MRI equipment that
  enters the magnet room has to be MR compatible.
• MRI examinations are safe and harmless, if these
  MRI risks are observed and regulations are
  followed.

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Safety concerns in magnetic resonance imaging
include

• The magnetic field strength
• possible 'missile effects' caused by magnetic
  forces
• the potential for heating of body tissue due to
  the application of the radio frequency energy
• the effects on implanted active devices such as
  cardiac pacemakers or insulin pumps
• magnetic torque effects on indwelling metal
  (clips, etc.)
• the audible acoustic noise
• danger due to cryogenic liquids
• the application of contrast medium

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MRI Safety Guidance

• It is important to remember when working around a
  superconducting magnet that the magnetic field is
  always on.
• Under usual working conditions the field is never
  turned off.
• Attention must be paid to keep all ferromagnetic
  items at an adequate distance from the magnet.
• Ferromagnetic objects which came accidentally
  under the influence of these strong magnets can
  injure or kill individuals in or nearby the
  magnet, or can seriously damage every hardware,
  the magnet itself, the cooling system.

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MRI Safety Guidance

• The doors leading to a magnet room should be
  closed at all times except when entering or
  exiting the room.
• Every person working in or entering the magnet
  room or adjacent rooms with a magnetic field has
  to be instructed about the dangers.
• This should include the patient, intensive-care
  staff, and maintenance-, service- and cleaning
  personnel, etc..

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MRI Safety Guidance

• Leads or wires that are used in the magnet bore
  during imaging procedures, should not form
  large-radius wire loops.
• The patients skin should not be in contact with
  the inner bore of the magnet.

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MRI Safety Guidance

• The outflow from cryogens like liquid helium is
  improbable during normal operation and not a real
  danger for patients

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MRI contrast

• The safety of MRI contrast agents is tested in
  drug trials and they have a high compatibility
  with very few side effects.
• The variations of the side effects and possible
  contraindications are similar to X-ray contrast
  medium, but very rare.
• In general, an adverse reaction increases with
  the quantity of the MRI contrast medium and also
  with the osmolarity of the compound.

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Cervical Spine 1 Basic

• Indications
• o Disc disease, pain, radiculopathy
• Sequences
• o Sag T1 FSE/TSE
• o Sag T2 FSE/TSE
• o Ax T2 FSE/TSE
• o Ax TOF GRE
• Optional
• o Cor T1 FSE/TSE
• o Cor T2 FSE/TSE
• For scoliosis, tethered cord and
  Neurofibromatosis, add coronal

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Cervical Spine 2 with contrast

• Indications
• Tumor, Infection, MS, Syrinx, Transverse
  myelitis
• Sequences
• Sag T1 FSE/TSE
• Sag T2 FSE/TSE
• Ax T1 FSE/TSE
• Ax T2 FSE/TSE
• Sag T1 C FSE/TSE FS
• Ax T1 C FSE/TSE FS
• Optional
• Cor T1 FSE/TSE
• Cor T2 FSE/TSE

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Cervical Spine 3 Trauma

• Indications
• o Trauma
• Sequences
• o Sag T1 FSE/TSE
• o Sag T2 FSE/TSE
• o Sag IR T2 FSE/TSE
• o Ax IR T2 FSE/TSE
• o Ax T2 FSE/TSE
• Can add sag T2 GRE to r/o hemorrhage

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Cervical Neurography (Brachial Plexus)

• Indications
• Post radiation therapy, eval for mass lesions,
  entrapment, denervation
• Sequences
• Sag T2 FSE/TSE Scout
• Cor STIR
• Cor T1
• AX STIR
• Ax T1
• Cor T1 C FS
• Ax T1 C FS
• Optional
• Cor T2 FSE/TSE FS
• Ax T2 FSE/TSE FS
• Sag T1 C FS

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Cervical Neurography (Brachial Plexus)

• Use the Cardiac or phased array Body coil rather
  than the spine coil
• Cor images should be 3mm skip 0mm, Ax Images 4mm
  skip 1.5
• FOV should be from C4 through T1
• Use T2 FSE/TSE FS if STIR images fail
• Can add flow suppression or sat bands above,
  below, and anterior
• Post process thick slab MIPs of STIR images if
  possible

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Thoracic Spine 1 - Basic

• Indications
• Disc disease, pain, radiculopathy
• Sequences
• Sag T1 FSE/TSE
• Sag T2 FSE/TSE
• Ax T1 FSE/TSE
• Ax T2 FSE/TSE
• Optional
• Cor T1 FSE/TSE
• Cor T2 FSE/TSE

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Thoracic Spine 2 with contrast

• Indications
• Tumor, Infection, MS, Syrinx, Transverse myelitis
• Sequences
• Sag T1 FSE/TSE
• Sag T2 FSE/TSE
• Ax T1 FSE/TSE
• Ax T2 FSE/TSE
• Sag T1 C FSE/TSE FS
• Ax T1 C FSE/TSE FS
• Optional
• Cor T1 FSE/TSE
• Cor T2 FSE/TSE

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Thoracic Spine 3 Trauma

• Indications
• Disc disease, pain, radiculopathy
• Sequences
• Sag T1 FSE/TSE
• Sag T2 FSE/TSE
• Sag IR T2 FSE/TSE
• Ax T2 FSE/TSE
• Optional
• Ax GRE
• Cor T1 FSE/TSE
• Cor T2 FSE/TSE
• Can add Sag GRE to rule out hemorrhage

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Routine L-Spine MRI

• Degenerative spine
• Sagittal T1 SE,
• Sagittal T2 FSE,
• angled axial PD/T2 FSE,
• Angled T1 stacked axials L3 to S2.
• No IV contrast.
•  

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L-Spine MRI

• Trauma L-Spine MRI
• Sagittal T1 SE,
• Sagittal FSEIR,
• Axial T2 FSE with fat sat.
• Target axials to abnormality.
• No IV contrast.
• Post-Op L-Spine MRI
• Sagittal T1 SE,
• Sagittal FSEIR,
• Axial T2 FSE with fat sat.
• Target axials to abnormality at level of surgery
• IV contrast.
• Can add Sag GRE to rule out hemorrhage

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Osteomyelitis, Discitis

• pre-contrast
• Sagittal T1 SE,
• Sagittal T2 FSE,
• Axial PD/T2 FSE,
• contrast Gd (0.1 mmol / kg to max of 20 cc)
• post-contrast
• Sagittal T1 SE,
• Axial T1 SE

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Tethered Cord

• Sagittal T1 SE,
• Sagittal T2 FSE,
• Axial T1 SE , T2 FSE,
• T10 to S2, using interslice gap as needed.
• No IV contrast.

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Spine Survey

• Indications
• Metastases, Non-localized infection, acute
  myelopathy / cord compression
• Sequences
• Sag T1 FSE/TSE
• Sag T2 FSE/TSE
• Ax T1 FSE/TSE
• Ax T2 FSE/TSE
• Sag T1 C FSE/TSE FS
• Ax T1 C FS (region of interest)
• Optional
• Cor T1 FSE/TSE
• Cor T2 FSE/TSE
• Comments
• sagittal images to determine where to obtain
  axial images

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MRI KNEE

• Common Indications
• Knee pain
• Knee instability
• Knee mass

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• First Ask
• Is there a mass?______ When did you first
  discover the mass?_______________________
• Does the problem relate to a recent injury? YES
  NO DATE_____________________
• Where does the knee hurt ( FRONT - BACK -
  INSIDE - OUTSIDE )?
• Have you had surgery on your knee? YES NO
  DATE__________________________
• Have you had an x-ray?
• If mass then schedule in early morning with
  Radiologist monitoring. Patient may need
  gadolinium
• Otherwise schedule anytime.
• Instruct patient to bring x-rays if available.

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Patient Preparation

•  Fill out safety screening and clinical
  information form
•  Vitamin E capsule on the site of symptoms and
  on any masses
•  Measure distance left or right from centerline
  of magnet

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• Coil Extremity. Slightly externally rotate the
  foot by about 10-15 degrees to stretch the
  anterior cruciate ligament.
• Pack some cushions around the knee to help it
  stay motion-free. A small cushion under the ankle
  helps to keep the leg straight.
•  
• Landmark inferior region of patella.
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• Patient Positioning Supine, feet first.

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• Series 1 Axial Proton Density
• Series 2 Sagittal Proton Density
• Oblique to the intercondylar notch
• Include all of medial and lateral menisci.
  Subcutaneous fat medial and lateral to knee joint
  may be excluded. If more slices are required,
  increase TR.

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• Series 3 Coronal Proton Density
• Oblique perpendicular to series 2.
• If more slices are required, increase TR.
• Keep TR gt 3000 and ETL lt 16
• If there is bone abnormality or soft tissue mass
  then it may be necessary to increase FOV.
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• Series 4 Coronal T2 Fat Sat (same as series 3
  above) 
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• Series 5 Optional Cartilage
• Usually cartilage is well seen on the proton
  density sequences (series 1-3). However this in
  patients with cartilaginous injuries, this extra
  sequence optimized for cartilage may be useful.
• Do not film this sequence. It is viewed on the
  computer work station.

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• If there is a Solid Mass suspicious for CANCER
• then make sure there is a vitamin E capsule
  marking the site of the mass and perform dynamic
  2D or 3D Gd MRA during the injection of single
  dose gadolinium followed by axial and either
  sagittal or coronal T1 fat sat spin echo sequences

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• If there is hemophilia or if PVNS is suspected
• Do a gradient echo sequence
• Series 8 Optional Gradient Echo
• This sequence is useful for patient with
  hemophilia or PVNS
• Make sure to cover all of the synovium

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