Imaging of vertebral column Flashcards
What are some red flags re: neck and back pain?
- Neurological symptoms or signs
- Significant trauma(mild trauma if age > 50)
- Unexplained weight loss
- Fever
- Age <22 or >55 years
- History of malignancy or immune compromise
- Osteoporosis or glucocorticoid use
- Suspicion of ankylosing spondylitis
What are some considerations re: red flags:
- Sinister pain (suggests malignancy)
- Fever
- Loss of weight
- Prior history of malignancy
- Infection risk
- Falls
- Difficulty walking or using hands
What are some yellow flags?
- Intravenous drug use
- Compensation or work injury issues
- Psychosocial stress
Why do CT and MRI predominate?
- High radiation dose associated with x-rays
- Most back pain is caused by soft tissue eg disc, cancer, infection and XRs don’t discriminate between soft tissues
- X-rays of the spine are all ‘abnormal’
So, in general?
- XR -Bones and alignment
- US -Paeds
- CT -Trauma
- MRI -Neurological, Cancer, Infection
- Nuclear medicine -Cancer activity
- Red flags - MRI
When is CT of cervical spine indicated?
- Commonly used in acute trauma, e.g. of high probability of C spine injury, *and investigation of cervical spine pain/radiculopathy without red flags
- Effective dose = 2mSv
What are some types of cervical spine trauma?
The most common fracture mechanism in cervical injuries is hyperflexion.
- Anterior subluxation occurs when the posterior ligaments rupture.
- Since the anterior and middle columns remain intact, this fracture is stable.
- Simple wedge fracture is the result of a pure flexion injury. The posterior ligaments remain intact. Anterior wedging of 3mm or more suggests fracture. Increased concavity along with increased density due to bony impaction. Usually involves the upper endplate.
- Unstable wedge fracture is an unstable flexion injury due to damage to both the anterior column (anterior wedge fracture) as the posterior column (interspinous ligament).
- Unilateral facet dislocation is due to both flexion and rotation.
- Bilateral facet dislocation is the result of extreme flexion. Unstable and associated with a high incidence of cord damage.
- Flexion teardrop fracture is the result of extreme flexion with axial loading. It is unstable and is associated with a high incidence of cord damage.
- Anterior atlantoaxial dislocation
Provide a checklist for assessing cervical spine CT
- Soft tissues
- Alignment – 3 lines, 3 planes
- Atlanto- axial joint
- Vertebral bodies
- Posterior Elements
- Facet Joints
- Intervertebral disc space
- Interspinous space
When do we use MRI?
- Red Flags
- Radiculopathy ^[as opposed to localised disease, usually a nerve origin along with sciatica] and degenerative disease - community setting
- Demyelination and neurological disease
How do we report MRI?
Discuss sequence:
- T1-weighted MRI (fat appears white)
- T2-weighted MRI (fat AND WATER appears white)
- also non-fat saturated
Also discuss plane:
- sagittal
- axial
- coronal
Also mention the region imaged (cervical, thoracic, lumbar), and presence of absence of contrast.
When identifying abnormalities, comment on region within vertebral column e.g. right paracentral zone L5-S1 disc protrusion.
What are some tips re: interpretinf MRI?
- anterior and posterior longitudinal ligament should look as thin black bands
- nucleus pulposus is more white compared to annulus fibrosus (black)
- disc should have rounded bottom: otherwise protrusion
- big dark black space = spinal cord edema
- discs should be intense, otherwise, decreased hydration
- increased focal points of intensity = lesion, malignancy
- ligamentum flavum appears as thin black line (otherwise ligamentum flavum hypertrophy causing spinal canal stenosis)
- cauda equina is posterior to CSF within dural sac. CSF is white and round on T2. If small = cauda equina syndrome
What are some structures you should count on MRI
v
- exiting (and transiting nerves if lumbar)
- subcutaneous fat
- CSF
- cauda equina
- facet joints
- ligamentum flavum
- annulus fibrosis
- nucleus pulposus
- epidural fat (small square of white, posterior to cauda equina, anterior to ligamentum flavum)
- thecal sac/dura
Distinguish between disc bulge and types of herniation
- disc bulge >90 angle, uses >25% of disc circumference. Can be circumferential or asymmetric
- disc protrusion, <25% of circumference, <90 angle
- disc extrusion and sequestration: direct line, straight out; break off
