Imaging of the Spine Flashcards
Why is the clinical history and examination important in imaging?
Decide which imaging is best
Urgency
What are plain films used for in the spine?
Alignment
Sometimes fractures
Why do we use MRI in the spine?
Spinal cord
Nerve roots
CSF
Ischaemia
Why are the bodies of lumbar vertebrae larger than the others?
Take more weight
What foraminae do cervical vertebrae have that others don’t?
Transverse foraminae
What are the costal facets in the thoracic vertebrae for?
Articulation with ribs
What can be accessed via the interlaminar space in the lumbar spine?
Spinal cord via needle
What are the features of the lumbar vertebral body in an A-P plain film?
Thin cortical bone
Pedicles look like hollow cylinders
Spinal canal in centres
When viewed laterally, what is the direction of the x-ray beam to the lumbar vertebral body in an A-P plain film?
Not entirely tangential
Shows as
- Thick superior cortical margin
- Double line at inferior margin
What direction is the x-ray beam in an oblique plain film of the spine?
Parallel to facet joint
45 degrees to body
What is the pars interarticularis part of?
Lamina
What is the importance of the pars interarticularis?
Thinnest and weakest part
Gets stress fractures
Which part of the intervertebral disc usually protrudes: anulus fibrosus or nucleus pulposus?
Nucleus pulposus
What is the signal of CSF in a T1 MRI?
Dark
What is the signal of CSF in a T2 MRI?
Bright
Where does the C1 spinal nerve exit?
Above C1 vertebra
Where does the C8 spinal nerve exit?
Below C7 vertebra
What is bright on both T1 and T2 MRIs?
Fat
What are the advantages of using MRI in the spine?
Shows pathology
What are the disadvantages of using MRI in the spine?
Time consuming
Expensive
Hard to access
What obscures many structures in the thoracic spine?
Ribs
Is irregularity in the endplates of the vertebrae normal or abnormal?
Usually normal in younger people
Can be indicator of pathology
Why are disc protrusions more common in the lumbar rather than thoracic spine?
Thoracic spine stabilised by ribs
What are the normal curves of the cervical, thoracic, and lumbar spines?
Cervical lordosis
Thoracic kyphosis
Lumbar lordosis
What is CT useful for in the spine?
Lumbar disc pathology but not as good as MRI
Bone detail
Complex joints
Multi-planar images
Why can the L4 vertebra slip on L5?
Arthritis of facet joint
Defect in lamina = stress fracture
What is bone scintigraphy?
Injected technetium emits gamma rays > counted by scanner
What takes up technetium?
Osteoblasts
What does bone scintigraphy assess?
Vascularity
Osteoblastic activity
Which areas show increased uptake of technetium in bone scintigraphy?
Pathology
Bladder because excreted in urine
Injection site
What is bone densitometry?
Dual energy x-ray absorptiometry
Low dose x-rays to measure bone mineral density
Compares bone mineral density of femoral neck/lumbar spine with age matched reference ranges/young normals
Combined with other clinical info can give risk of fracture
