Transcript MRI SPINE

MRI SPINE /KNEE
DR, Mohamed El Safwany, MD.
Intended learning outcome
• The student should learn at the end of this
lecture MRI aspects of spine and knee.
TISSUE COLOURS
• Water and pathology:
– White on T2,
– dark on T1.
– Pathology stays white on FLAIR, water doesn't
TISSUE COLOURS
• Fat:
– white on T1 and T2
– dark on STIR and out of phase
TISSUE COLOURS
• Hematoma: varying with time
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
TISSUE COLOURS
•
Tumor: hypervascular (neovascularity):
– white with gadolinium
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
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.
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.
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.
Indications:
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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)
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.
• 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).
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.
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;
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.
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..
MRI Safety Guidance
• Leads or wires that are used in the magnet
bore during imaging procedures, should not
form large-radius wire loops.
• The patient’s skin should not be in contact
with the inner bore of the magnet.
MRI Safety Guidance
• The outflow from cryogens like liquid helium is
improbable during normal operation and not
a real danger for patients
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.
Cervical Coil
Cervical Spine 1 – Basic
• • Indications
– o Disc disease, pain, radiculopathy
• • Sequences
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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
Cervical Spine 2 – with contrast
• • Indications
– Tumor, Infection, MS, Syrinx, Transverse myelitis
• • Sequences
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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
Spinal Coil
Thoracic Spine 1 - Basic
• • Indications
– Disc disease, pain, radiculopathy
• • Sequences
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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
Thoracic Spine 2 – with contrast
• • Indications
– Tumor, Infection, MS, Syrinx, Transverse myelitis
• • Sequences
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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
Thoracic Spine 3 – Trauma
• • Indications
– Disc disease, pain, radiculopathy
• • Sequences
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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
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
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
Spine Survey
• • Indications
– Metastases, Non-localized infection, acute myelopathy / cord compression
• • Sequences
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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
MRI KNEE
• Common Indications
– Knee pain
– Knee instability
– Knee mass
• 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.
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
• 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.
• 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 > 3000 and ETL < 16
If there is bone abnormality or soft tissue mass then it may be
necessary to increase FOV.
• 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.
• 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
Text Book
• David Sutton’s Radiology
• Clark’s Radiographic positioning and
techniques
Assignment
• Two students will be selected for assignment.
Question
• Define The standard views in the basic spinal
MRI scan to create detailed slices?
•
Thank You