Imaging VC guide Flashcards
What are the relevant imaging modalities of teh spine?
- XR -Bones and alignment: falling out of favour due to high dose, soft tissues issues contributing to back pain, and physiological variation that can easily be mistaken for pathological issues
- US -Paeds e.g. when suspecting spina bifida
- CT -Trauma
- MRI -Neurological, Cancer, Infection
- Nuclear medicine -Cancer activity
- Red flags - MRI
How to report iamging
- XR: projection (frontal: AP/PA, lateral, oblique, APOM); plane; region imaged; patient details: rotation, quality, exposure, non-organic objects; identify normal and abnormal structures
- standard cervical projections: AP, lateral, APOM ^[if vertebrae down to T1 are not visible, a swimmer’s view may be useful]
- standard thoracic projections: AP and lateral ^[if upper thoracic spine is not visible on lateral, swimmer’s view may be useful]
- standard lumbar projections: AP and lateral - CT: plane; modality; region imaged; window (bone? soft tissue? ^[lung for chest CT]); patient details: quality and exposure, inorganic objects; normal and abnormal structures
- MRI: imaging modality (T1/T2); plane; region imaged; contrast vs no contrast; patient details: quality and exposure, inorganic objects; normal and abnormal structures
Describe use of XR
While X-ray imaging of the spine is much less common than CT and MRI, it is still important to know the imaging principles:
- a minimum of two projections, 90 degrees from each other is required - due to superimposition of anatomic structures, localisation of pathology, visualisation of fracture and alignment
- three projections are required (minimum) for joints: AP/PA, lateral and oblique
- R and L sides should be compared
- current and previous images where available should be compared
Describe appearance of structures on XR
- air is black (radiolucent), as are cysts ^[OA], IV discs
- fat is dark grey
- soft tissue is grey
- bone is off white, as are osteophytes, sclerosis
- metal is white (radioopaque), as are effusions
List structures to identify on XR
Cervical AP
![[Pasted image 20240128190016.png]]
- vertebrae
- body
- IV disc (black)
- uncus
- pedicles
- laminae
- spinous processes
- transverse processes
- superior articular processes
- inferior articular processes
- zygapophysial joints
- lateral mass
- skull
- ribs
- clavicle
- manubrium of sternum
## Cervical lateral
![[Pasted image 20240128190027.png]]
- Atlas
- anterior arch and posterior arch
- Axis
- body
- dens
- superior articular process
- inferior articular process
- spinous process
- Cervical vertebrae
- body
- IV disc (black)
- pedicles
- laminae
- spinous processes
- superior articular processes
- inferior articular processes
- zygapophysial joints
- Skull
- Ribs
- Clavicle
- hyoid
Cervical APOM
![[Pasted image 20240128190037.png]]
- Atlas
- anterior arch and posterior arch
- lateral mass
- superior articular process
- inferior articular process
- transverse process
- Axis
- body
- dens
- superior articular process
- inferior articular process
- spinous process
- skull
- mandible
Thoracic AP
![[Pasted image 20240128190047.png]]
- vertebrae
- body
- IV disc
- pedicles
- laminae
- spinous process
- transverse process
- superior articular process
- inferior articular process
- zygapophysial joint
- clavicle
- ribs
- head
- shaft
- costotransverse joint
- costovertebral joint
Thoracic lateral
![[Pasted image 20240128190059.png]]
- vertebrae
- body
- IV dic
- pedicles
- laminae
- spinous process
- superior articular process
- inferior articular process
- zygapophysial joint
- IV foramen
- ribs
Lumbar AP
![[Pasted image 20240128190115.png]]
- vertebrae
- body
- disc
- pedicle
- lamina
- spinous process
- transverse process
- superior articular process
- inferior articular process
- zygapophysial joint
- sacrum
- promotory (i.e. the cupped ridge)
- ala
- foramina
- S1 superior articular processes
- SI joint
- pelvis
- PSIS
- PIIS
- ribs
- psoas major
Lumbar lateral
![[Pasted image 20240128190130.png]]
- vertebrae
- body
- disc
- pedicle
- lamina
- spinous process
- transverse process
- superior articular process
- inferior articular process
- zygapophysial joint
- IV foramen
- sacrum
- pelvis
- ribs
Describe use of CT
CTs are commonly used in acute trauma settings, especially where there is a high risk of cervical spine injury, or in investigating cervical pain or radiculopathy in the absence of red flags.
Uses a relatively lower radiation dose compared to XR.
As with X-R: we need a minimum of three planes to extract the maximum information, as well as three windows (in general).
Describe appearance of structures on CT
Same as X-ray.
Soft tissue windows will show soft tissue structures in high definition.
Bone windows will show bone in high definition.
List structures to identify on CT
- soft tissues
- Atlanto- axial joint
- Vertebral bodies
- Posterior Elements
- spinous processes
- Facet Joints
- Intervertebral disc space
- Interspinous sp
Describe use of MRI of spine
We use MRI in three specific instances:
- red flags (see below)
- radiculopathy and degenerative disease, particularly in the acute setting
- demyelination and neurological disease
We also require three planes and three sequences (T1, T2, T2 fatsat) to get the maximum amount of information.
Describe appearnce of structures on MRI
It depends on the sequence.
T1:
- bone: lighter grey
- water/CSF: BLACK
- discs: light grey fairly uniform
- nerve fibres: spinal cord and cauda equina dark grey. Exiting nerve looks like vertebral body density, transiting lools smaller and darker
- ligaments: thin black or dark grey lines ^[inc in intensity suggests hypertrophy eg of ligamentum flavum]
- muscles: lighter grey
- fat: e.g. epidural, white
-
T2:
- bone: dark grey, facet joints grey
- water/CSF: white
- discs: light grey annulus, dark nucleus pulposus ^[decrease in intensity suggest dessication]
- nerve fibres: cauda equina light grey, spinal cord slightly darker grey. Exiting nerve looks like vertebral body (grey) density, transiting looks smaller and darker
- ligaments: thin black or dark grey lines ^[inc in intensity suggests hypertrophy eg of ligamentum flavum]
- muscles: black
- fat: white
T2 fatsat:
- fat appears dark
List structures to identify on MRI
- vertebral bodies: body, facet joint, spinous and transverse processes
- surrounding muscles: e.g. psoas major and quadratus lumborum, erector spinae in lumbar spine
- exiting (and transiting nerves if lumbar)
- subcutaneous fat
- CSF
- cauda equina
- facet joints
- ligamentum flavum
- anterior and posterior longitudinal ligament
- annulus fibrosis
- nucleus pulposus/disc depending on projection
- epidural fat (small square of white, posterior to cauda equina, anterior to ligamentum flavum)
- thecal sac/dura
- unusual foci of intensity: lesion
Describe Wiltse zones
Describe how to identify exiting and transiting nerves, and the effect of disc bulge
Distinguish between types of disc bulges
- disc bulges, protrusion, extrusions and sequestrations:
- disc bulge: note that if bottom margin is not smooth and circular, suggests bulge
- Protrusion indicates that the distance between the edges of the disc herniation is less than the distance between the edges of the base.
Extrusion is present when the distance between the edges of the disc material is greater than the distance at the base.
