Head, Neck, and Spinal Column Imaging Flashcards
MR imaging is dependent on the biologically changeable parameters of the:
Proton density (PD)
Longitudinal relaxation time (T1)
Transverse relaxation time (T2)
What can pulse sequences characterize?
Chemical and physical structures of a pathology over time
What is an additional method to more accurately define lesions?
Multiplanar imaging
What are flow-sensitive pulse sequences and MR angiography used to show?
Vascular structures and their blood flow
How is brain function investigated using MR?
By having the patient perform mental tasks. Any changes are noted in the regional cerebral blood flow and oxygenation level (for example, have the patient stare at a specific spot: occipital lobe will have increased blood flow)
Which imaging sequences are used to demonstrate cerebral infarcts?
Diffusion weighted imaging sequences (DWI). Areas of restricted diffusion are highlighted during post-processing techniques
What type of imaging is used to determine axonal pathways connecting functional areas in the brain?
Diffusion tensor imaging
What information does MR spectroscopy provide?
The biochemistry and metabolism of tissue
How are catastrophes avoided in the magnet room?
With proper screening of patients, equipment, and personnel for ferromagnetic materials, pacemakers, and other MR incompatible devices
What are the clinical indications for brain imaging?
Multiple sclerosis and other white matter diseases such as encephalitis and herpes
Primary tumour assessment/metastatic disease
AIDS (toxoplasmosis)
Infarction (TIA vs. CVA)
Hemorrhage
Hearing loss
Visual disturbances
Infection
Trauma
Unexplained neurological symptoms/deficits
Preoperative planning
Temporal lobe epilepsy, non-hemorrhagic brain contusions, and traumatic shear injuries are also seen in the early stages
What does pituitary gland (sella turcica) imaging show?
Flow of contrast in and out of the pituitary gland
Multiplanar imaging of paediatric anatomy gives important information about:
The corpus callous and posterior fossa structures
The superior gray/white matter contrast allows accurate assessment of:
Myelination and cortical abnormalities
Blood flow voids within arteries are shown with which sequences?
Spin-echo imaging sequences
MR angiography is used to demonstrate which pathologies?
Vascular stenosis, occlusions, aneurysms, AVMS, as well as cavernous angiomas
Which pulse sequence is the gold standard for imaging of the central nervous system?
Conventional spin-echo. It produces good tissue contrast and has a high sensitivity for abnormalities. Often used in paediatric imaging
Advantages of FSE sequences
Reduces scan time, most sensitive for detecting brain pathology
Which brain pathology is PD imaging mostly used for?
Multiple sclerosis
What are the minimum and maximum number of coils/channels for a head coil?
2 and 32
What is a transceiver?
Both transmits and receives RF pulses. Quadrature coils (volume coil). Uses two coils to transmit a signal to the patient as well as receive a signal back from the patient. Obtains a uniform signal across the entire FOV
How many component are the 1.5T and 3.0T HNS coils composed of?
5 separate components labeled A to E
How many elements are there in the 1.5T and 3.0T HNS coils?
29
What are HNS coils designed to do?
To eliminate multiple coil usage per patient in order to increase throughput and patient comfort
What is the patient position for a routine brain procedure?
Supine, head in the head coil with shoulders usually resting against the lower margin of the head holder
How should the IPL be aligned for brain imaging?
Parallel to the couch
What is the landmark for routine brain imaging?
The nasion
What alternate position can be used for brain imaging if the patient condition doesn’t allow for a supine?
A lateral decubitus position
What does it mean for the patient positioning to be isocenter?
All three planes are aligned
Routine brain slice prescription:
Axial sequence: programmed off the sagittal localizer
Sagittal and coronal sequences programmed off the axial localizer
What is the typical adult FOV for brain imaging?
23cm
What is the slice thickness/spacing for routine brain?
Medium slices/gap
5-6mm/2mm
(5mm is more common)
Routine brain: Sagittal/sagittal oblique
May have to angle slices to compensate for rotation
Scan left to right
Include temporal lobes and area from foramen magnum to the top of the skull
What are the first and last slices for a sagittal routine brain?
First: left lateral temporal lobe
Last: right lateral temporal lobe
Routine brain: Axial/ axial oblique
May have to angle slices to compensate for rotation
Scan inferior to superior
Include foramen magnum to superior brain. Include all brain surface and soft tissue laterally. Always have the spinal cord.
Angle to the anterior-posterior commissure axis
Routine brain: Coronal/coronal oblique
May have to angle slices to compensate for rotation
Scan posterior to anterior
Include cerebellum to frontal lobe. Include spinal cord inferiorly and parietal bones superiorly
What are the first and last slices for an axial routine brain?
First: foramen magnum
Last: superior brain surface
What are the first and last slices for a coronal routine brain?
First: posterior cerebellum
Last: frontal lobe
Do thinner slices increase or decrease scan time?
Increase
What is the typical scan time for a sequence for routine brain?
2-4 minutes
What resolution is used for imaging smaller organs in the brain?
High-resolution imaging. Smaller slice thickness
Larger (fine) matrix (small pixels)
Reduction in the total number of slices for the specific anatomy
What is the patient position for temporal lobes?
Supine, head in head coil, shoulders at inferior margin of it, IPL parallel to couch
What is the landmark for temporal lobes?
At the nasion
What are the clinical indications for temporal lobes?
Lesions, vascular malformations
Leukodystrophies, atrophic processes
Temporal lobe epilepsy
Hippocambus changes
What is the most common clinical indication for temporal lobes?
Temporal lobe epilepsy
When scanning temporal lobes, what do changes in the hippocampus indicate?
Alzheimer’s disease
What do we try and angle to for temporal lobes?
Parallel to the hippocampus
Temporal lobes: Sagittal T1 - whole brain
This will provide a data set for the remaining pulse sequences
Medium slices/gap: 5-6mm
Left to right throughout the whole head
Include the area from the foramen magnum to the top of the head (FOV)
Temporal lobes: Axial Oblique FSE T2
Thin slices/gap: 2-4mm
Improves spatial resolution
Angled parallel to the temporal lobes
Scan inferior to superior from the inferior aspect of the temporal lobes to the superior border of the body of the corpus callosum
Occipital to frontal lobes are included in the FOV
Temporal lobes: Coronal Oblique FSE T1
Thin slices/gap: 2-4mm
Increases spatial resolution
From posterior cerebellum to anterior border of the genu of the corpus callosum
Angled parallel to axial slices (textbook)
Angled perpendicular to the Sylvian fissure (clinical)
What is the most important imaging sequence/plane for hippocampal disease?
Coronal Oblique FSE T1
Temporal lobes: 3D coronal GRE T1 (Spoiled)
Shows small tumours in the temporal lobes (volume imaging provides thin slices with no gaps)
Medium number of slices (64)
Sequence is often used for post-gadolinium studies
Images can be reformatted in all three imaging planes
What are inversion recovery (IR) pulse sequences used to show?
A specific tissue type - can be T1 or T2 weighted
IR provides images that can null (saturate) a specific tissue
What is IR timing based on?
The recovery time of the tissue being nulled
Why are IR sequences used for imaging temporal lobes?
Since white matter disease can be subtle, eliminating the normal white matter tissue will help demonstrate a small temporal lobe lesion. Signal will be nulled from white matter if we use an inversion time of around 300ms
What are common artifacts when imaging temporal lobes?
Flow from carotid and vertebral arteries
Magnetic susceptibility on the coronal T1 spoiled GRE
What are some remedies for magnetic susceptibility artifact? (temporal lobes)
Cannot remove petrous ridges, use SE sequences
Decrease TE
Increase bandwidth
What are some remedies for flow artifacts? (temporal lobes)
Spatial presaturation pulses inferior to the FOV
Gradient moment nulling (GMN) (increases minimum TE time - reserved for T2 W imaging as this pulse sequence has along TR time)
What are some clinical indications for the IAC/posterior fossa?
Acoustic neuromas - vertigo, hearing loss, and tinnitus are symptoms Numbness in the face Posterior fossa lesion Hemi facial spasm Trigeminal neuralgia
IAC/Posterior fossa: Sagittal T1 or GRE T2*
Can be bilateral or unilateral imaging Most common is bilateral Thin slices/gap: 2-4mm From left to right through the IAC Medial to lateral from the foramen magnum to the superior border of the body of the corpus callosum in the FOV
IAC/Posterior fossa: Coronal T1
Demonstrates the IAC well
Posterior cerebellum to the clivus
Thin slices/gap: 2-4mm
Angle parallel to the IAC
IAC/Posterior fossa: Axial or Axial Oblique FSE T2
Thin slices/gap: 2-4mm, 3mm
Fin matrix 512x512 with small FOV
Inferior to superior from foramen magnum to the superior border of the petrous ridges
Slices angled parallel to direct both IAC
IAC/Posterior fossa: Axial 3D FSE T2 or T2* GRE
High contrast images are produced Increased SNR No gap Isotropic Small (32) to medium (64) number of slices for volume
Which imaging planes are best to demonstrate the IAC?
Axial and coronal
What are some imaging characteristics of the IAC?
Inherent tissue contrast between CSF and nerves
CSF bright on T2, nerves hypointense on T1 and T2
T2 W images are often used, negate the need for gadolinium
NEX/NSA usually increased due to fine matrix to increase SNR
What is the artifact when imaging IAC/posterior fossa?
Flow from venous sinuses if including the posterior fossa in imaging
What is the remedy for flow artifact? (IAC/posterior fossa)
GMN (increases minimum TE)
Spatial presaturation bands S and I (saturates venous flow)
Peripheral gating in extreme cases of severe flow artifacts
What imaging sequences are used to image the temporal lobes?
Sagittal T1 (Whole brain) Axial oblique FSE T2 Coronal oblique FSE T1 3D Coronal GRE T1 (spoiled) IR
What are the imaging sequences used to image the IAC/posterior fossa?
Sagittal T1 or GRE T2*
Coronal T1
Axial/axial oblique FSE T2
Axial 3D FSE T2 or T2* GRE
What are some clinical indications for trigeminal neuralgia?
Trigeminal neuralgia facial pain/spasm Vascular compression Lesions Trigeminal schwannoma/neuroma Neurofibromatosis
What are the imaging sequences used for trigeminal neuralgia?
Axial oblique
Axial volume imaging
Coronal FSE T1/T2
Trigeminal neuralgia: Axial oblique
Thin slices/gap
Slices programmed inferior to superior from foramen magnum to tectum (clinically to the orbits, some sites request to include C3 inferiorly)
Angled perpendicular to the brain stem
Trigeminal neuralgia: axial volume imaging
Programmed straight
Reconstruct using oblique angles
Thin slices/no gaps
Fine/large matrix
Trigeminal neuralgia: coronal FSE T1/T2
Medium slices/gap
From posterior to anterior from pons to anterior face
Include sinuses and mandible
Angled parallel to the brainstem
What are some clinical indications for the pituitary fossa/sella?
Abnormal pituitary gland functions (hyperprolactinemia, Cushing’s disease, acromegaly, hypopituitarism, diabetes insipidus, amenorrhea)
Hypothalamic disorders
Visual field defects
Pre and postoperative follow up pituitary adenomas
What imaging sequences are used to image the pituitary fossa/sella?
Sagittal T1
Coronal FSE T1
Post-contrast studies
Pituitary Fossa/Sella: sagittal T1
Thin slices/gap
Left to right to include lateral borders of the pituitary fossa, include inferior edge of the sphenoid sinus to the superior portion of the lateral ventricles
Angled parallel to the falx cerebri (angled off the coronal)
Pituitary Fossa/Sella: Coronal FSE T1
Thin slices/gap: interleaved
From posterior clinoids to anterior clinoids
Include the border of the sphenoid sinus to the superior portion of the lateral ventricles
Angle slices perpendicular to the floor of the sella (if programmed off sagittal)
Angle slices perpendicular to the midline of the brain (if programmed off axial)
What are pituitary post-contrast studies?
Dynamic scanning - coronal
Timed sequences
Microadenomas are difficult to demonstrate
Spoiled GRE T1 sequences are performed due to faster scanning
Half dose of gadolinium
Why is timing of scans important for pituitary post contrast studies?
Because both pituitary gland and microadenomas enhance
30, 60, 90, 120, 180 seconds
Which enhances first in post contrast studies, the pituitary gland or a microadenoma?
The pituitary gland
What are some artifacts when imaging the pituitary fossa/sella?
Flow from COW
Aliasing/wrap from small FOV
What is the remedy for flow artifact? (Sella)
Spatial presaturation bands S and I; R and L may be used
What are the remedies for aliasing? (Sella)
Apply oversampling techniques
Increase FOV
What are the clinical indications for orbits?
Proptosis
Visual disturbances
Evaluation of orbital or ocular lesions
Which alignment light passes through the orbits for orbital imaging?
The horizontal alignment light
What are the instructions you should give to the patient prior scanning the orbits?
Remove makeup
Assume a fixed gaze, straight ahead with eyes open ones head is positioned within the head coil or specific surface coils
Which imaging sequences are used to image the orbits?
Sagittal FSE T1
Axial FSE T1 or T2
Coronal FSE T1/T2/STIR
Orbits: Sagittal FSE T1 (whole head)
Medium slices/gap: 5-6mm
Left to right side of brain
L37mm to R37mm
From foramen magnum to the top of the head
Orbits: coronal FSE T1/T2/STiR
Thin slices/gap
From posterior aspect of the chiasm to the anterior border of the globe
Angle parallel to a line jointing the posterior orbital margins
Fat sat technique is applied to the coronal FSE T2 pulse sequence
Orbits: Axial FSE T1 or T2
Thin slices/gap
Slices may be programmed straight for bilateral or angled parallel to the optic nerve
From inferior margin of the orbits to above the optic chiasm (or superior orbital margin)
Imaging considerations for orbits:
Fine matrix, small FOV for increased spatial resolution
Increase NEX/NSA required for SNR
Retro-orbital fat must be saturated out
Chemical/spectral presaturation techniques
STIR pulse sequences to null fat
Which pulse sequence is required for optic neuritis?
Coronal T2 fat sat pulse sequence
What are some artifacts when imaging the orbits?
Eye motion
Flow from COW
Aliasing
What are the remedies for eye motion when imaging the orbits?
Request patient to focus the eyes
What are the remedies for COW and carotid flow when imaging the orbits?
Use GMN and place spatial presaturation bands S and P to the FOV for COW flow
Place situation bands I to the FOV for carotids
What are the clinical indications for sinuses?
Staging of neoplasms
Inflammation
Polyps
Endoscopic sinus surgery is being performed with open magnets
Where is the horizontal alignment light for sinuses?
At the nasion
Sinuses: Sagittal T1
Medium slices/gap
L37mm to R37mm
Whole head is included
Coverage is from foramen magnum to the top of the head
Sinuses: Coronal FSE T1/T2/STIR
Medium slices/gap
From posterior portion of the sphenoid sinus to the tip of the nose
Include all the paranasal sinuses
Inferior margin of the sphenoid sinus to the superior border of the fontal sinus
Sinuses: Axial
Medium slices/gap
From inferior border of the maxillary border to the superior edge of the frontal sinus
What artifacts are associated with the sinuses?
Flow from carotids, vertebral, and jugular arteries
Why are multiple NEX/NSA required for sinus imaging?
For low SNR due to low proton density of air-filled cavities
Where is contrast enhancement seen in sinus imaging?
In the mucosal lining of the sinuses
Why is contrast used in sinus imaging?
To distinguish between enhancing tumours and non-enhancing effusions (fluid filled sinuses)
What are some clinical indications for the pharynx?
Staging of oropharyngeal carcinoma Pharyngeal and para-pharyngeal masses Demonstration of benign lesions Investigation of sleep apnea Swallowing disorders Inflammation
What is the patient positioning for pharynx?
Same as brain positioning
Where does the horizontal alignment light pass for pharynx imaging?
Through the angle of the mandible
Which imaging planes are used for pharynx?
Typically all three imaging planes
When is the head coil used when imaging the pharynx?
When evaluation the skull base, oropharynx, and nasopharynx
When is the anterior neck coil used when imaging the pharynx?
When the cervical nodes are being investigated
Nasopharynx: Axial oblique
Thin slices/gap
Slices prescribed from mid-cervical spine to cribriform plate
Angled parallel to the nasopharynx/airway
Nasopharynx: coronal
Thin slices/gap: 2-4mm
Fine matrix 512x512
Multiple NEX/NSA
From mid-cervical spine to frontal and maxillary sinuses
Nasopharynx: Sagittal
Thin slices/gap: 2-4mm
Program slices from left to right mandibular rami
Pharynx: coronal
Thin slices/gap: 2-4mm Fine matrix 512x512 Multiple NEX/NSA From posterior border of the cervical cord to the anterior surface of the neck From skull base to SC joints
Pharynx: axial
Thin slices/gap: 2-4mm
Fine matrix 512x512
Multiple NEX/NSA
From thyroid cartilage to the base of the skull
Increase area of coverage superiorly if nodal or pharyngeal disease is suspected
(we typically include nasopharynx and pharynx in our coverage)
Pharynx: sagittal
Thin slices/gap: 2-4mm
Fine matrix 512x512
From left to right to include lateral walls of the pharynx on either side
Area of coverage includes skull base to thyroid cartilage
What type of SNR is in the pharynx and why?
Poor SNR due to the composition of the anatomy
What pathologies require the anterior neck coil when imaging the pharynx?
Cervical lymph nodes and lymph node metastases
Why are fat saturation techniques uneven when imaging the pharynx?
Due to the shape of the anatomy (wide shoulders, narrow neck)
Why is FSE used in conjunction with a rectangular FOV when imaging the pharynx?
To reduce scan times due to the large/fine matrix and increased NSA/NEX
What are some artifacts associated with imaging the pharynx?
Flow from carotid, vertebral, and jugular arteries
Swallowing, especially with patients who have tumours
Respiratory motion from breathing motion moving the anterior neck coil
What is the remedy for flow artifacts in the pharynx?
Use GMN (increases minimum TE), used with T2 W Spatial presaturation band/pulses placed S to I to the FOV
What is the remedy for swallowing artifact in the pharynx?
Patient communication - instruct patient to swallow as little as possible
If there’s a buildup of saliva in the pyriform fossa, instruct the patient to swallow and then scan the next pulse sequence
What is the remedy for respiratory artifacts in the pharynx?
Instruct the patient to breathe slowly
Place a small foam pad between the patient’s chest and the coil
What are some clinical indications for the larynx?
CA of larynx
Pre-surgical screening
Disorders of the vocal cords and phonation
What is the poisoning for larynx imaging?
Supine, head and neck straight
Placement of a soft pad under the neck allows for the vertical alignment light to be located midway between the posterior and anterior neck surfaces of the neck
Which coil is used for imaging of the larynx?
Anterior neck coil
Where does the horizontal alignment light pass for the larynx?
Through the thyroid cartilage
Larynx: axial
Thin slices/gap: 2-4mm
Slices prescribed to include laryngeal cartilages and vocal cords
Angled parallel to the larynx for tumours limited to the vocal cord
Rarely just perform larynx - usually a pharynx is performed
Which imaging planes are used to image the sinuses?
Axial, sagittal, and coronal
Which imaging planes are used to image the nasopharynx?
Axial oblique, coronal, and sagittal
Which imaging planes are used to image the pharynx?
Coronal, axial, and sagittal
Larynx: sagittal
Thin slices/gap: 2-4mm
Slices prescribed on either side of the longitudinal alignment light from the left to the right lateral skin surfaces of the neck
Area of coverage will include from the superior border of the hard palate to the SC joints
Axial - Coronal
Thin slices/gap: 2-4mm
Angled parallel to the larynx
Area of coverage includes the superior border of the hard palate to the SC joints
Are technical considerations, artifacts and remedies for larynx the same as for the pharynx?
Yes
What are some clinical indications for the thyroid/parathyroid glands?
Retrosternal goiter
Carcinomas
Parathyroid adenomas (glandular lesions)
What is the positioning for the thyroid/parathyroid glands?
Same as pharynx
Where does the horizontal alignment light pass for the thyroid glands?
Just inferior to the thyroid cartilage
What equipment is used for the thyroid glands?
Anterior neck coils/volume neck coil
Immobilization foam pads/straps (if applicable)
Ear plugs
What imaging planes are used to image the thyroid glands?
Coronal and axial
Thyroid glands: coronal
Thin slices/gap
204mm
Fine matrix 512x512
Scan from posterior thyroid to anterior thyroid
Area of coverage includes from the mandible to the arch of the aorta
Thyroid glands: axial
Thin slices/gap
Slices scanned through the thyroid gland
From mandible to the arch of the aorta
Chemical/spectral presaturation pulse sequences may be used (STIR)
Thyroid glands have the same artifacts and remedies as what anatomical part?
The pharynx
Do parathyroid glands demonstrate a high signal on FSE T2 or T1 W images?
FSE T2 W images
Which presaturation techniques are used when imaging thyroid glands?
Chemical/spectral presaturation techniques are used
Fat saturation or STIR pulse sequences
What are some clinical indications for the salivary glands?
Salivary gland masses
Staging of neoplasms and nodal involvement
What is the positing when parotids are clinically indicated for salivary gland imaging?
Same as brain but horizontal alignment light passes through the EAM
What is the positing when submandibular/cervical nodes are clinically indicated for salivary gland imaging?
Same as pharynx (include floor of mouth within the coil)
Where does the horizontal alignment light pass for salivary gland imaging?
Through the angle of the mandible
Soft pad may be placed under the patient’s neck
Which imaging planes are used to image the salivary glands?
Sagittal and coronal
Salivary glands: sagittal
Thin slices/gap
Prescribed from left to right through the gland in question
Area of coverage includes the base of the skull to the hyoid bone
Salivary glands: coronal
Thin slices/gap
Mainly used for imaging parotid glands
Slices are scanned from vertebral bodies to the superior alveolar process
Include cervical lymph node chain and the base of the skull in the FOV
Which imaging plane is mostly used to image the parotid glands?
Coronal plane
When is MR sialography used?
For ductal obstructions
Heavily T2 W images are acquired
How is SNR optimized when imaging salivary glands?
Correct coil selection
What does using a rectangular FOV do when imaging the salivary glands?
Shortens scan time
Why is multiple NEX/NSA used when imaging the salivary glands?
Due to thin slices/fine matrix
Which pulse sequences require fat suppression techniques when imaging salivary glands?
FSE T2 sequences
Which TE, TR, and ETL are used for parotid duct imaging?
Long TE (250ms) Long TR (10s) Long ETL (16-20s)
What type of imaging is often used for parotid duct imaging?
3D imaging
Artifacts in the salivary glands are the same as what other body part?
The pharynx
Where does phase ghosting occur in axial and coronal imaging planes when imaging salivary glands?
What will this interfere with ad how is this artifact reduced?
Along the R to L axis - this will interfere with the parotid glands which are positioned lateral to the neck
Swapping phase axis in the S to I direction reduces this artifact
What is required to prevent aliasing when swapping phase and frequency?
Oversampling
Which imaging planes are used to image the spine?
Sagittal and axial/axial oblique
C-spine: sagittal
Program off a coronal localizer Scan left to right Cover area from left lateral vertebral border to the right Cover base of skull to T2 Thin slices Routine: 3mm/0.5mm Cord compression: 3mm/0 Phase direction: A to P Frequency direction: S to I May use presaturation techniques to reduce swallowing artifacts
C-spine - axial oblique
Program off a sagittal T2
Scan superior to inferior
Include C2-C3 disk to C7-T1 disk
Angle slices parallel to disks
May use a block of slices or separate disk slices
If tumour involvement, a block of slices is required
Thin slices: 3mm/0.5
Phase direction: A to P
Frequency direction: L to R
Use anterior presaturation techniques placed along the trachea to reduce swallowing artifacts
T-spine: sagittal
Program off a coronal localizer Scan left to right Cover area from left lateral vertebral border to right Include C7 to conus medullaris Thin slices Routine: 3/0.5 Cord compression: 3/0 Phase direction: A to P Frequency direction: S to I Swapping of phase and Fq is common
How do you reduce respiratory/cardiac artifacts in a sagittal T-spine?
Use of presaturation techniques
May use gating techniques
Increase scan time (not often used)
T-spine: axial oblique
Program off a sag T2
Thin slices
Slices angled parallel to disk
Angle perpendicular to any tumour (may not require an angle)
Syrinx or large tumours: medium to large slices; cover vertebral body above and below tumour
Include C7-T1 disk to T12-L1 disk
Phase direction: A to P
Frequency direction: L to R
Include oversampling technique (no phase wrap)
T-spine: coronal
Program off a sag T2 Thin slices: 3/1 Medium slices for large tumours, AVM Thin slices for cord lesions Phase direction: R to L Frequency direction: S to I May swap phase and fq Oversampling techniques used Angle parallel to the cord Include area from spinous process to anterior vertebral body for scoliosis
L-spine: sagittal
Program off a coronal localizer
Scan left to right – cover area from left lateral vertebral border to right
Cover conus to sacrum
Thin slices
Routine: 3/1
Cord compression: 3/0
Phase direction: A to P Frequency: S to I
Rectangular FOV
May use presaturation techniques for flow artifact from aorta
L-spine: axial oblique
Program off a sag T2 Thin slices Minimum lower 3 disk levels Slices angled parallel to disk Include lamina above to lamina below Phase direction: A to P Frequency direction: L to R Include oversampling technique (no phase wrap)
L-spine: coronal
Program off a sag T2 Thin slices: 3/1 Medium slices for large tumours, AVMs Thin slices for cord lesions, cover area from posterior cord to anterior cord Phase direction: R to L Frequency direction: S to I May swap phase a fq Oversampling techniques used Angle parallel to the cord Include area from spinous process to anterior vertebral body (scoliosis)
Which imaging planes are used to image the brachial plexus?
Axial, sagittal, and coronal
Brachial plexus: coronal
Program off a sag localizer Scan posterior to anterior Cover from posterior cervical cord to SC joints Include area from C3 to aortic arch Thin slices: 3/1 Phase direction: R to L Frequency direction: S to I May swap these two Oversampling techniques used Presaturation techniques used in S to I reduce artifact from carotid and jugular arteries
Brachial plexus: axial
Program off coronal Thin slices Cover area from C3 to arch Superior to inferior Phase direction: A to P Frequency direction: L to R Oversampling technique (no phase wrap)
Brachial plexus: sagittal
Program off a coronal or sagittal Scan medial to lateral Cover area from outside spinal cord (opposite side) to shoulder joint Thin slices: 3/1 Phase direction: A to P Frequency direction: S to I Presaturation used Gating techniques can also be used
What categories are spinal lesions divided into?
Extradural, intradural-extramedullary, and intramedullary
What is the most common chronic ailments?
Neck or back pain
What should be included when imaging the spine?
The intervertebral disks, spinal canal, spinal cord, nerve roots, neuroforamina, facet joints, and soft tissues within and surrounding the spine
Which pulse sequence is mandatory to assess damage to the spinal cord in the cervical and thoracic regions?
A T2 W sequence
What must pulse sequences be tailored to when imaging the spine?
To counteract CSF flow and physiologic motion
Which coil is most commonly used when imaging the spine?
Multi-coil array spinal coil
What is the total number of elements used in the 1.5T and 3.0T HNS coils?
29
What were HNS coils designed to do?
To eliminate multiple coil usages per patient in order to increase throughput and patient comfort
How is the curve of the spine placed closer to the coil?
By the use of supporting pads under the shoulders for C-spine and under the patient’s knees for L-spine
What is a common method used to reduce cardiac, respiratory, and CSF pulsation artifacts when imaging the spine?
Switching the phase and frequency encoding axes to orient the phase axis along the long axis of the spine
What may switching the phase and frequency encoding axes result in?
It may increase the chemical-shift artifact along the posterior margins of the vertebral bodies and may obscure thoracic disc herniations
Why do posterior surface coils reduce artifacts resulting from physiologic motions anterior to the spine?
Because of their inherent property of signal drop-off with increasing distance from the coil
What can disk herniation occur with?
With an intact but thinned annulus (similar to protrusion above) or with frank rupture of the annulus and extrusion of the nucleus pulposus through the defect
What is disk prolapse?
A herniated disk covered by a few remaining annular fibers
What is disk protrusion? When is it classified as a large protrusion?
When an eccentric disk extends 3mm or less beyond the vertebral margin
If it’s more than 3mm, we call it a large protrusion
What criterion has been applied to disk extrusion?
The waist or neck of the disk fragment must be smaller than its width on axial views
What is another name for a free fragment?
A sequestration - no longer attached to the parent disk
What is more important, why size or shape of the abnormal disk or its location and relationship to the nerve roots?
Its location and relationship to the nerve roots
What are some clinical indications for c-spine imaging?
Cervical cord compression, disk, or trauma
Spinal infections or tumours
Arnold Chiari malformations and cervical syrinx
MS plaques within the cord
What anatomy must be included in the coil for c-spine?
From the base of the skull to SC joints
Where is the horizontal alignment light for c-spine?
At the level of the hyoid bone
Where does cervical disk disease most commonly occur?
At the levels of C5-6 and C6-7
What are common symptoms of a central disk herniation (c-spine)?
Most likely causes myelopathy by compressing the spinal cord, along with neck pain and stiffness
If the disk extends laterally to compress nerve roots, the pain may radiation the shoulder, arm, or hand
What are some clinical indications of the t-spine?
Metastases of the thoracic spine is the most common indication
Symptomatic thoracic disks are uncommon, and the most level disks are seen at T11-T12
MS plaques
Visualization of the inferior extend of a cervical syrinx
Thoracic syrinx
What anatomy must the coil cover for the t-spine?
From the top of the shoulders to the lower costal margin (to include the conus)
Where is the alignment light for t-spine?
At the level of T4
What are some clinical indications for l-spine?
Degenerative disk disease Spinal dysraphism (assesses cord termination, syrinx, and diastematomyelia/ tethered cord) Discitis Conus evaluation Arachnoiditis Mechanical back pain
What anatomy must the coil cover for l-spine?
From the xiphoid to the bottom of the sacrum
Where is the alignment light for the l-spine?
At the level of L3 (just below the lower costal margin)
The cord does not extend below what vertebral body?
L1
In general, why are lumbar images better than those of the thoracic and cervical?
Because there are fewer artifacts from CSF pulsations, and cardiac and respiratory motions have little effect in the lumbar region
Which level should scans of the l-spine be focused on and why?
Levels L3-S1 because the lower lumbar spine is usually the source of symptomatic degenerative disease
Why should one of the sagittal views of the l-spine include the conus medullar is and upper lumbar region?
To exclude a higher lesion that could be responsible for radicular-type symptoms
What are some clinical indications for whole spine imaging?
Cord compression Bone marrow screening Congenital abnormalities Syrinx Leptomeningeal disease
Where is the horizontal alignment light for whole spine imaging?
At a point midway between the sacrum and the base of the skull which corresponds to approximately 2cm below the sternal notch
What anatomy is included in whole spine imaging?
Entire canal from the base of the skull to below the sacrum
Scanning is commonly split in two or three sections
What slice thickness is used for whole spine imaging?
Thin slices/gap
