9. Spiral (helical) CT
• 90’s
• Speed
– Patient acceptance
– Different phases of contrast
enhancement
• Volumetric data set
– Multiplanar and 3D
reconstructions
10. Multidetector (multislice) CT
• Late 90’s to present
• 0.175 - few seconds scan
time
• Overlapping =
reconstructions
• Contiguous = speed
• Original: 4 slice
• 2nd generation: 16, 64
• New: 256; 320
25. Image interpretation
• Anatomy
• Cross sectional techniques:
– CT
– MRI
• Nomenclature of disc herniations and spinal
stenosis
• A few cases
26. NOMENCLATURE
• Consistent
• Reflect common usage where appropriate
• Surgically relevant
• ‘Able to visualize over the phone’
• 2 morphological characteristics:
– Nature of disc pathology
– Location
• Able to add further descriptors
– Neural structures
– Clinical context
• www.asnr.org/spine_nomenclature/reporting
27. Disc bulge
• Generalised extension of disc tissue beyond
intervertebral disc space
• ‘Generalised’ = >50% circumference (>1800)
• Relatively short distance, <3mm
28.
29. Herniated disc
• Localised displacement of disc material beyond
intervertebral disc space (ie bony margins excluding
osteophytes) OR break in vertebral end plate (Schmorl’s
node)
• ‘Localised’ = <50% circumference (<1800)
– ‘Broad based’ = 25 - 50% circumference (>900)
– ‘Focal’ = <25% circumference (<900)
• ‘HNP’ not accurate
– Herniation may include NP, cartilage, annulus, bone
• ‘Rupture’ tends to refer to trauma/ acute event
• ‘Prolapse’ and ‘bulging disc’ outdated
• ‘Localised disc bulge’ = oxymoron
32. Sequestered disc
• Extruded disc material that has no continuity with
the disc of origin
• = free fragment
• Migrated disc:
– Disc material displaced away from site of extrusion
34. Location of herniation
• Anatomic system that correlates with surgery
• Landmarks, transverse plane:
– Sagittal and coronal planes at centre of disc
– Medial edge of articular facet
– Medial, lateral borders of pedicles
40. Volume: degree of canal
compromise
• X-sectional area at site of maximal narrowing
• ‘Mild’: <1/3
• ‘Moderate’: 1/3 – 2/3
• ‘Severe’: > 2/3
• Same grading for foraminal narrowing as seen in
sagittal plane
• Other descriptors such as compression of
specific neural structures
42. Image interpretation
• Anatomy
• Cross sectional techniques:
– CT
– MRI
• Nomenclature of disc herniations and spinal
stenosis
• A few cases
43. • 85 year old female
• Severe acute on chronic mechanical back pain
– Can’t sleep
– Limited walking to only a few steps
• Spontaneous onset
• No known trauma
44. What is the most likely diagnosis?
1. Acute disc herniation
2. Facet joint degeneration
3. Crush fracture secondary to osteoporosis
4. Metastatic cancer
45. What is the most appropriate
imaging modality?
1. Plain film
2. CT
3. Scintigraphy (bone scan)
4. MRI
53. • 68M
• Sudden onset bilateral leg pain and weakness
• Urinary retention
54. What is the most likely diagnosis?
1. Guillain Barre syndrome
2. Cauda equina syndrome
3. Crush fracture secondary to osteoporosis
4. Discitis/ osteomyelitis
55. What is the most appropriate
imaging modality?
1. Plain film
2. CT
3. Scintigraphy (bone scan)
4. MRI
56.
57.
58. • Dx: Cauda equina syndrome
• Cause: massive sequestration
• Other causes:
– Tumour
• Primary of lower cord: ependymoma
• Primary of nerve: BPNST
• Primary of dura: meningioma
• Primary of vertebral body: chordoma, giant cell
tumour
• Secondary
– Trauma