Test 2: CT of the Spine Flashcards
(84 cards)
1
Q
Indications for CT of the spine
A
- MRI contraindicated
- before and after spinal surgery (bony anatomy, alignment of hardware)
- visualize fractures, including pars defects
- characterize osseous lesions: neoplasm/metastases, hemangioma, bone cyst, osteoid osteoma
2
Q
Spine CT: contrast or non contrast?
A
NON
3
Q
Best imaging modality to view spinal cord?
A
MRI
4
Q
If a patient is contraindicated to get an MRI, but needs imaging of an IV disc, what type of imaging will be used?
A
CT, soft tissue window
5
Q
What imaging findings might come with a pars defect? What imaging modality is a pars defect best seen, and why?
A
anterolisthesis, elongated, flute shaped spinal canal, horizontal lucency at pars interarticularis in sagittal and axial CT views
-CT best: too much overlap on XR
6
Q
Burst fracture: characteristics on CT
A
- break in cortical continuity (areas of lucency)
- narrowed spinal canal
- loss of height of vertebral body
- vertebral body misshapen
- may see fragments displaced posteriorly into spinal canal
7
Q
Vertebral augmentation: define the concept and list 2 procedures
A
- procedures used for palliation of pain related to vertebral compression fractures
- 2 types: percutaneous vertebroplasty (PV) and balloon-assisted kyphoplasty
8
Q
management of compression fractures
A
- initially: conservative management is the gold standard
- medical management with or without methods of immobilization
- medication
9
Q
complications of medication for treatment of pain in compression fractures:
A
NSAIDS: gastrointestinal hemorrhage, ulcers
Narcotics: addiction, constipation, nausea, somnolence
10
Q
osteoporotic fractures: talk about pain, medication, and what happens over time
A
most patients have a spontaneous resolution of pain within 4-6 weeks of onset, even without medication
11
Q
extra credit: causes of vertebral compression fractures
A
- osteoporosis (most common)
- direct trauma
- neoplasm/metastatic disease
12
Q
indications for vertebral augmentation
A
- conservative treatment failed
- pain refractory to oral medications for 6-12 weeks
- contraindications to medication
- hospitalization with IV narcotics administered
13
Q
Define percutaneous vertebroplasty
A
Injection of low viscosity PMMA cement into vertebral body using a unipedicule or bipedicule needle
14
Q
Success rate for pain relief? who benefits most?
A
89-93% success rate; women and people <75 years old benefit most
15
Q
Percutaneous Vertebroplasty: Clinical History/Physical exam criteria for indication/contraindication of PV procedure:
A
- focal pain at spinal process level corresponding to level of fracture
- 6-12 weeks after onset of pain: time frame for treatment (first 6-12 conservative)
Patients treated EARLIER if:
-they required hospitalization and IV narcotics for pain
-they have a history of a successful prior PV
DISQUALIFICATION for PV:
-radicular pain involving LEs or LBP radiating to hips (pt may need a different intervention)
16
Q
PV: complications; acute and delayed
A
ACUTE: 1-3.9%
-cement leak: symptomatic or asymptomatic
-cement pulmonary embolism: symptomatic or asymptomatic
-bleeding
-infection
-neurological deficit
DELAYED:
-risk for new fractures at other levels: cement decreases compliance
-clustering of fxs as a natural history of OP?
17
Q
Balloon kyphopasty: explain the procedure
A
insertion of a unipedicle or bipedicle needle, inflation of intravertebral balloon to create a void in which high-viscosity bone cement is injected
-more recently developed (than PV?)
18
Q
Between Balloon kyphoplasty and PV:
- which has better outcomes?
- which has fewer complications?
- which has better height restoration?
- which is better for burst fxs?
- which is more expensive?
A
- no difference in outcomes
- no difference in complications
- “some believe” kyphoplasty offers better height restoration
- kyphoplasty may be better for burst fxs; can offer more controlled angular and fracture correction
- kyphoplasty more costly
19
Q
is cement bright or dark on CT?
A
bright
20
Q
osseous metastasis: appearance on XR, CT
A
heterogenous, patchy appearance within bone
21
Q
Indications for CT myelogram:
A
- pt has a need for visualization of soft tissue within spinal canal:
- pt cannot get an MRI
- pt has hardware that obscures spinal canal on CT or MR
22
Q
CT myeologram: technique
A
- injection of contrast by lumbar puncture (into thecal sac) under fluoroscopic XR guidance
- subsequent imaging of spine
23
Q
CT myelogram: contraindications
A
-elevated INR or bleeding disorders
24
Q
MRI indications: 6 main categories
A
- degenerative disease
- osseous/extraosseous infection
- neoplasm
- demyelinating/inflammatory disease
- trauma
- postop spine imaging
25
MRI: absolute and relative contraindications
```
ABSOLUTE:
-pacemaker
-ferromagnetic aneurysm clip
-cochlear implant
-IVC filter
-orbital metallic foreign body
RELATIVE
-metal fragments, depending on location
-1st trimester pregnancy (risk v. benefits)
-transcutaneous nerve stimulators
-claustrophobia
```
26
Contrast enhanced MRI: indications
- postop spine recurrent back pain evaluation: to view granulation tissue from recurrent or new disc herniation
- metastatic bone disease (bone and spinal cord)
- primary SC lesions (tumor, demyelination)
- spinal infection (discitis, osteomyelitis, epidural abscess)
27
Noncontrast MRI: indications
- degenerative disease
- low back pain
- preoperative planning
- radiculopathy
28
Contraindication for MRI contrast
Pt with EGFR <30
- measure of kidney function
- risk of nephrogenic system fibrosis (NSF)
29
Non Contrast MRI for Cervical Spine: what sequences are used for the cervical spine, and which views for each sequence?
Cervical spine:
- T1 and T2: sagittal and axial views
- STIR: sagittal view
- Gradient Echo: axial view
30
Non Contrast MRI for Thoracic and Lumbar Spine: sequences used and views
Thoracic/Lumbar Spine:
- T1 & T2: sagittal and axial
- STIR: sagittal
31
why might an MRI be better than an XR or CT in the case of viewing a fracture?
the age of the fracture can better be determined by the presence or absence of fluid/edema in the bone and surrounding area. newer fracture=edema in bone
32
```
MRI Basics: T1 weighted image
hyperintense (bright) or hypointense (dark)?
-water:
-fat:
-normal bone:
-sclerotic bone:
```
- water: hypointense
- fat: hyperintense
- normal bone: hypointense
- sclerotic bone: markedly hypointense
33
```
MRI Basics: T2 weighted image
hypo/hyperintense?
-water:
-fat:
-normal bone:
-sclerotic bone:
```
- water: hyperintense
- fat: hyperintense
- normal bone: hypointense
- sclerotic bone: markedly hyperintense
34
```
MRI Basics: STIR
hypo/hyperintense?
-water:
-fat:
-normal bone:
-sclerotic bone:
```
- water: hyperintense
- fat: hypointense
- normal bone: hypointense
- sclerotic bone: markedly hyperintense
35
What are water-rich structures that will show up on MRI?
- CSF
- normal disc space
- bone/soft tissue edema
- fluid collections: cysts, abscesses, postop seroma
36
How does aging affect normal bone appearance on MRI?
Yellow (fatty) bone marrow increases with normal aging; so a younger bone will appear darker on MRI than an older bone
37
Calcified ligament or disc: hypointense or hyperintense on MRI?
Hypointense (sclerosis)
38
C-spine exiting nerve root numbering
Exiting nerve root named for the lower vertebra
Ex) at C5-C6, exiting nerve roots are C6
C7-T1: C8 nerve roots
39
T-spine exiting nerve root numbering
Exiting nerve roots from the level above
| ex) at T1-T2, exiting nerve roots are T1
40
zygapophyseal joints: anatomy and function
facet joints
-articulation point of 2 vertebrae
-composed of inferior and superior articular processes
-put your hands up like you're going give somebody a high 10: your hands are oriented like superior facets
-point your hands down, keeping your palms facing your body: your hands are oriented like inferior facets
function:
-carry axial load of body
-limit spine ROM
-form posterior border of intervertebral foramen
41
intervertebral neural foramina
- foramen through which spinal nerves exit the spinal canal
- within foramen, motor and sensory nerve roots become mixed spinal nerves ("exiting nerve")
- facet joints make up the back of this foramen
- more or less directly inferior/superior to vertebral pedicles of vertebrae above and below
42
where does the spinal cord terminate? what happens then?
terminates at L1-L2 (conus medullaris) then becomes cauda equina
43
contents: cauda equina
pia-wrapped 3-5 lumbar nerves, 5 sacral nerves, 1 coccygeal nerve
-cuada equina is still within the thecal sac
44
sciatic nerve
Contains fibers from the anterior and posterior branches of the lumbosacral plexus
L4-S3
-sensory: skin of whole leg
-motor: hamstrings, lower leg, ankle/foot
45
cervical spine XR: list views
- AP
- AP open mouth (odontoid)
- Lateral (must include T1, need to see prevertebral soft tissues)
- bilateral oblique
- flexion
- extension
46
cervical spine XR AP open mouth view: what are we looking for?
- alignment of odontoid process
- C1/C2 alignment
- lateral masses
47
cervical XR AP view: what are we looking for?
-alignment: single row, top to bottom. including:
uncovertebral joint alignment
TP, SP alignment
48
cervical lateral XR view: what to look for
- IV disc spaces
- prevertebral soft tissue
- SPs
- facet joints
49
cervical XR lateral view: maneuvers to enhance views of lower C-spine
- swimmer's view: elevate arm nearest cassette
- cervical spine CT
- pull down on arms during cross table lateral (pt supine, shoulders depressed)
50
cervical XR lateral view: what bony landmarks to use to analyze alignment
- anterior column of vertebrae: vertebral bodies
- posterior column: SPs
- middle column: facets
- Sps: middle of anterior spinous process lines up C1-C3 (WHAT DOES THIS MEAN?)
51
pseudosubluxation of C2 and C3: cervical XR
normal in children due to joint laxity; may be seen in up to 20% of children under age 8
52
predental space: cervical XR; define and give norm values
distance from dens to C1 body
- adult: 3mm
- child: 5mm
53
cervical spine: oblique XR view; what is best viewed?
head turned to best expose neural foramina
- foraminal stenosis
- facet joints
- pedicles
54
cervical spine flexion and extension XR views: 2 main reasons
- helps detect ligamentous injury (instability) not apparent on neutral view
- assessment of RA at C1-C2 and any associated instability
55
Cervical spine XR, flexion view-Vertebral body angulation/translation patterns of instability
Criteria for instability at C-spine
1. 3.5 mm translation
* **"vertebral body subluxation should be no greater than 1mm as compared to extension view"
2. 1.7mm or greater disc space widening
3. angulation between 2 adjacent vertebra of 11 degree or more
56
ADI measurements: what is it, norms for adults, children
- atlantodens interval: distance between the anterior aspect of the dens and the posterior aspect of the anterior ring of the atlas.
- adults: ADI <3.5mm
57
Type I dens fx
<5%
| -(usually unstable) fracture through tip of dens at attachment for alar ligament
58
Type II dens fx
>60% (most common type)
- fracture through the base of the dens
- no alar involvement-relatively stable (in my notes, but later type II fx is listed as an unstable fx)
59
Type III dens fx
30%
- subdentate (does not involve dens)
- through the body of C2
- unstable-atlas and occiput can move together as a unit
60
what type of injury most commonly results in cervical spine fracture?
hyperflexion injury
61
c-spine flexion injuries: list 7 types
1. anterior subluxation: anterolisthesis
2. simple wedge fx: stable, fx of vertebral body
3. unstable wedge fx: interspinous ligaments involved
4. unilateral interfacet dislocation: "jumped facet"
5. bilateral interfacet dislocation: "jumped facet"
6. flexion teardrop fx
7. anterior atlantoaxial dislocation
62
jumped facet: define
top vertebrae "jumps forward": inferior facet of top vertebra lies anterior to superior facet of inferior vertebra
- can be unilateral or bilateral
- unilateral: 50% anterolisthesis
63
jumped facet: imaging characteristics
- anterolisthesis
- widening of interspinous distance
- widening of facet jt
64
3 types of extension injuries in the c-spine
1. hangman's fx
2. extension teardrop fx: avulsion at anterior vertebral body
3. hyperextension with pre-existing spondylosis (disc degeneration)
65
hangman fx: bony areas affected, injury type, what is seen in imaging
- fx involving both par interarticularis of C2
- secondary to hyperextension and distraction
- imaging: shows fractures at bilateral lamina and pedicles and usually anterolisthesis at C2-C3
66
Jefferson fx: bony areas affected, how it happens, imaging characteristics
- burst fx of C1 (UNSTABLE)
- axial loading (diving into shallow water)
- open mouth anterior view: bilateral, lateral offset of C1 on C2
- lateral view: widening of ADI if transverse ligament affected
67
list 3 cervical flexion injuries that are UNSTABLE
1. bilateral interfacetal dislocation
2. flexion teardrop fx
3. wedge fx with posterior ligamentous rupture
68
list 3 cervical extension injuries that are UNSTABLE
1. odontoid fx type II
2. Hangman's fx
3. extension teardrop fx
69
what views are taken for lumbar spine X rays?
lateral, oblique
70
Lateral lumbar XR: what is visualized
- IV disc spaces
- SPs
- pedicles
- alignment
- vertebral body height
71
what is viewed on the lumbar oblique XR view?
Scotty dog!
- Nose: TP
- Eye: pedicle
- Front leg: inferior articular facet
- Neck of dog: pars interarticularis
72
common site for pars defects
L4/L5
73
common site for anterolisthesis-lumbar
L5/S1
74
spondylolisthesis: lumbosacral spine; 2 major types
Lumbo Sacral Spine L5-S1
- anterolisthesis: forward slippage
- retrolisthesis: backward slippage
75
spondylolisthesis: 5 major types/causes
1. dysplastic: caused by defect in formation of part of vertebra
2* Isthmic: pars defect
3* Degenerative: caused by arthritic changes
4. Traumatic: usually pedicle, lamina, or facet jt fx
5. Pathologic: caused by abnormal bone (e.g. tumor)
*most common!
76
spondylolisthesis: Grades
```
Grade I: 0-25%
Grade II: 25-50%
Grade III: 50-75%
Grade IV: 75-100%
Grade V: >100% (spondyloptosis)
```
77
spondylolysis
- defect of lumbar vertebrae at pars interarticularis
- pars located anterior to lamina and posterior to pedicle
- typically secondary to stress fx from repetitive injury
78
spondylolisthesis in C-spine: example
hangman's fx
79
Thoracic Lumbar spine fxs: flexion fractures
1. compression fx: anterior parts of vertebral body breaks, loses height; posterior part intact (usually stable)
2. axial burst fx: vertebra loses height both anteriorly and posteriorly
3. chance fx: seatbelt injury
80
thoracic/lumbar spine fxs: rotation fxs
1. transvers process fx: uncommon, rotation or extreme lateral bending
2. fracture dislocation: involves bone and soft tissue, vertebra may move off an adjacent vertebra; unstable
81
Wedge fx: thoracic
compression fx secondary to hyperflexion and compression
- buckled anterior cortex with loss of height of anterior vertebral body
- anterosuperior fx of vertebral body
- most common in thoracic spine
- considered serious if: fx involves adjacent vertebrae, anterior wedge >50%, severe hyperkyphosis, bone fragments suspected within spinal canal
82
chance fracture: describe, most common location?
T12-L2: thoracolumbar junction
- flexion fracture primarily (also extension, but it's classically thought of as a flexion injury)
- seatbelt injury: compression injury to anterior vertebral body; transverse fx through posterior vertebral body and posterior elements
83
Schmorl's node: describe
- vertical disc herniation through cartilaginous vertebral body endplates
- may or may not be symptomatic
- common with increasing age
- strong heritability >70%
84
Sacrum: views, features
AP view: SI joints, sacral ALA, coccyx
| Lateral view: sacral coccygeal angle, cortical integrity, pre-sacral soft tissue (tumor involvement)
