imaging midterm Flashcards
fluffy texture
both osteoblastic and osteoclastic activity
smudged texture
osteomalacia
coarsening
chronic renal failure and osteoporosis
lacy, delicate texture
thalassemia
sclerosis
normal local increases due to increases physical stress
reactive: in diseased area
4 periosteal rections
solid: benign
laminated or onion skin: repetitive injury
spiculated or sunburst: malignant bone lesions
codman’s triangle: triangular shape
6 categories of skeletal pathology
congenital
inflammatory
metabolic (only diffuse)
neoplastic (only diffuse)
traumatic
vascular
distribution of lesion
monostatic or monoarticular: one bone or joint
polyostotic or poly articular: multiple bones/joints
diffuse: nearly all bones or joints
behavior of lesions
osteolytic: destroyed by osteoclastic activity
osteoblastic: new bone present
mixture
osteolytic lesions (3 forms of destruction)
geographic: sharp borders - benign
moth-eaten: ragged borders - malignant
permeative: poorly defined borders - malignant
crossed joint space
tumors do not cross the joint space
infections do cross the joint space
buttressing
osteophytes at joint margins to strengthen
tumor matrix
chondroid: cartilaginous - stippled, popcorn shaped
osteoid: bony - white, cloud-like, fluffy
purposes of written radiology report
link radiologic signs
comparison of other radiographs
permanent record
expedites treatment
research
communication
findings in radiology report
body of report
complete sentences
do not state diagnosis
paragraphs based on ABCS
conclusion of radiology report
state diagnosis here in order of severity
vision statement 2020
doctors of PT
new technologies … provide direct care
comprehensive level of professional care
military PTs providing primary care since
early 1970s
do you see superimposition with CT?
CT’s are relatively free of superimposition
CT radiodensities
dense: white or light gray
less dense: dark
pixel
represents a slice anywhere from 0.1 to 10 mm thick
voxel
product of pixel and slice thickness
can contain different tissues in single voxel
volume averaging
radiodensity is average for all radio-densities in that voxel
can result in loss of contrast resolution
can be solved with thinner slices, but loss of image quality
scout image
small locator image inserted into image for each slice
windowing
range of radiodensities displayed in an image
examples of image degradation
hardening
streak artifacts
motion artifacts
hardening
as photons pass through structures such as the skull, beam becomes harder since lower-energy photons are absorbed more readily
artifacts: metals
lead to streaking represented by bright lines in image
motion artifacts
pt moves leading to shading or streaking in image
slice thickness
thinner: less radiodensity and increases “noise”, require greater radiation to produce same image quality
what does CT image best?
bone:
fractures
degenerative changes
may be first choice in serious trauma
spinal stenosis (myelography)
condition of IVD (diskogram)
evaluation of loose bodies in joint
less time consuming than MRI or US
measurements of osseous alignement
less expensive than MRI
less problematic for claustrophobia
limitations of CT
histological makeup due to reliance on radiodensities
relatively high radiation exposure
planes of MRI
coronal: from front, facing pt
axial: from below
sagittal: left to right for either side of body
T1 weighted image
much of energy from RF pulse remains in tissues
fat gives high signal intensity
water gives low signal
red bone marrow - intermediate signal
yellow marrow - high
T2 weighted image
low energy levels
grainer and display less spatial resolution
fat gives low signal
water gives high signal
what structures give low signal on both T1 and T2?
tendons
ligaments
menisci
cortical bone - very low
what structures give intermediate signal on both T1 and T2?
muscles - slightly lower on T2
cartilage
what does MRI image best?
sensitive for changes in bone marrow
soft tissue detail
can replace invasive diagnostics in detection of meniscal tears
disk herniations and other nerve root impingement
can stage neoplasms in bone and ST
contraindications for MRI
ferrous metals:
~ ferromagnetic surgical clips can be displaced
~ orthopedic hardware can distort image, but
generally no health risk
pacemakers may malfunction due to magnet
claustrophobia
may need to sedate those who cannot stay still
who gives guidelines for spine radiology?
american college of radiology (ACR)
none from APTA
goal of cervical spine radiographic examination
ID or exclude anatomic abnormalities or disease processes or spine
indications of cervical spine radiologic examination
trauma
shoulder or arm pain
occipital headache
limitation on motion
planned or prior surgery
eval or primary or secondary malignancies
arthritis
suspected congenital anomalies and syndromes with
spinal abnormality
eval of spinal abnormality seen on other iamges
follow up of known abnormality
suspected spinal instability
basic projections (cervical)
AP
lateral
AP open mouth - as needed
swimmer’s lateral - if needed to assess lower cervical
segments and cervicothoracic junction
bilateral oblique - if needed to assess neural foramina
flexion-extension - to assess instability
canadian C-spine rule
alert and stable
sustained traumatic injury
3 questions
- are there any high risk factors that mandate radiography? if yes, obtain
- any low risk factors that allow safe assessment of ROM? if no, obtain
- is pt able to rotate neck actively at least 45 degrees to right and left? if no, obtain. if yes, no need.
100% sensitivity
43% specificity
NEXUS
National Emergency X-radiography Utilization Study
low risk criteria to help identify pts following trauma that do not need imaging based on clinical presentation.
must meet all five for no imaging
- no posterior midline cervical tenderness
- no evidence of intoxication
- normal level of alertness and consciousness
- no focal neurological deficit
- no painful distracting injuries
99.6% sensitivity
12.9% specificity
ACR guidelines for suspected spinal trauma recommends:
CT with sagittal and coronal reformatting ot both CT and MRI to assess instability or myelopathy
cross table lateral
performed on supine, immobilized patient
preliminary diagnostic screen
lateral flexion and extension stress views
give joints more opportunity to reveal instability by imposing mechanical stress
radiologic signs of cervical spine trauma
soft tissues: widened retropharyngeal and retrotracheal spaces, displacement of trachea, larynx or prevertebral fat pad (6mm at C2 and 22mm at C6)
vertebral alignment: loss of parallelism or lordosis, acute kyphosis, rotation of vertebral body
joint signs: widened ADI, widened interspinous process space, widened IVD space, narrowed IVD space, loss of facet joint articulation
stable injuries
protected from significant bone or joint displacement by intact posterior spinal ligaments
compression fractures, traumatic disk herniations
unstable injuries
significant displacement initially or have potential to become displaced with movement
dislocations
potential injury to spinal cord and nerves
C1-C2 and C6-C7 most frequently injured
40% incidence of associated neurological injury
approximately 2/3 of all spinal cord injuries in C-spine
SCIWORA syndrome
spinal cord injury without radiographic abnormalities
spinal cord injured without fracture or dislocation
predominant in children
causes ligamentous injury and cartilaginous vertebral endplate fractures
in adults, buckling of ligamentum flavum by posterior vertebral body osteophytes can result in central cord syndrome
MOI of c spine fractures
either direct force (blow to head) or indirect force (rapid accel or decel in motor vehicle accident)
characteristics of c spine fractures
alvusion: fragment pulled off by violent muscle contraction
compression/impaction: adjacent vertebrae forced together
~ axial: burst fracture
~ flexion: compresses vertebral body into an anterior
wedge shape
~extension: force fractures and compresses articular
pillars
wedge fracture (C3-C7)
when interposed vertebra is compressed anteriorly by two adjacent vertebrae owing to hyperflexion forces
~2/3 of these are at C5-C7
~may be stable because ligamentous structures at
least partially intact
burst fracture (C3-C7)
occurs when IVD axially compressed and NP driven through an adjacent vertebral endplate, causing literal bursting apart of vertebral body and resulting in comminution
~ can be stable or unstable
teardrop fracture (C3-C7)
occurs when triangular fragment of bone becomes separated from anteriorinferior corner of vertebral body because of either avulsion or compression force
~ flexion fracture most severe
~ potentially unstable
articular pillar fracture (C3-C7)
fractures by a compressive hyperextension force combined with a degree of lateral flexion
~ most frequently at C6 and usually stable
Clay Shoveler’s fracture (C3-C7)
avulsion fracture of spinous process produced by hyperflexion forces or forceful muscular contraction of trapezius/rhomboids often associated with repetitive heavy labor or upper extremities
~ most frequently at C6-T1
~stable
transverse process fracture (C3-C7)
uncommon fracture but usually occurs at largest transverse process in c-spine (C7)
~ usually from lateral flexion forces causing avulsion at tip of contralateral TP
dislocations (C-spine)
direction that superior vertebra of segment moved
what is the most serious and life-threatening injuries to c-spine?
fracture-dislocations
~ fracture through base of dens combines with
ligament rupture
~hangman’s fracture associated with anterior
dislocation of C2 on C3
dislocations not associated with fractures
either complete or self-reducing
~ SR return to normal alignment once force dissipates
locked facets
inferior articulating process of uppermost vertebra will lie in front of superior articulating process of subjacent vertebra
~ locking joint out of normal articulation
facet dislocations
unilateral: tear one facet capsule and posterior ligaments. stable in absence of vertebral body subluxation
bilateral: unstable due to extensive disruption of posterior ligaments, facet joint capsules, annulus fibrosus and sometimes anterior longitudinal ligament
C1-C2 rotary subluxation and dislocation
forces of flexion or extension combine with rotation to cause one inferior facet of C1 to slip anterior to superior facet of C2 and become fixed in this position
hyperflexion sprains (c-spine)
disrupt posterior ligament complex
~ tears of posterior ligs allow superior vertebra of
segment to rotate anteriorly on its subjacent
vertebra
hyperextension sprains (c-spine)
when neck forced past end ranges of extension
~ isolated injury or rebound action
~ disrupt anterior ligs and ST, posterior sublux
treatment of c-spine sprains
immobilization
pain management
rehabilitation
intervertebral disk herniation
resulting in nerve root compression uncommon in c-spine
~ may cause posterior or lateral disk herniation resulting in neural compression
~ pt seeks medical attention for radiation arm pain
~ more commonly herniate without causing neural compression
images are of little diagnostic value
treatment of IVD herniation
NSAIDs
modalities to relieve symptoms
~ spinal traction, joint mobilization
surgery if conservative fails
degenerative diseases of c spine
~ degenerative disk disease
~ degenerative joint disease
~ foraminal encroachment - diminished dimensions
~~ only ossified changes shown on radiograph
~ spondylosis - osteophyte formation
~ spondylosis deformans - advanced spur formation
~ diffuse idiopathic skeletal hyperostosis - flowing ossification along anterior vertebral bodies and disk spaces
schmorl’s nodes
intravertebral herniation of NP through endplate into spongiosa of vertebral body
rehabilitation of c-spine can include:
- segmental mobilization techniques to restore joint mobility
- therapeutic exercise to balance muscle strength and flexibility
- promote optimal posture
- pt education on occupational and leisure activity accommodations that decrease stressful postures or maladaptive behaviors
- therapeutic modalities such as cervical traction, heat/cold, and ultrasound to provide relief of acute symptoms
goal of T-spine radiologic examination
identify or exclude anatomic abnormalities or disease processes of spine
routine t-spine projections
AP and lateral
swimmer’s lateral view (t-spine)
pt’s arm overhead to remove superimposition of shoulder from obscuring lower cervical and upper thoracic
oblique t-spine
demonstrate facet joints
thoracolumbar or other coned views (t-spine)
close up view
cone refers to circular aperture on xray tube which limits expose field
recommended rib projections
done in sections due to superimposition
entire rib cage not radiographed
AP or PA
oblique for axillary ribs
PA chest to rule out pneumothorax or hemothorax
AP view demonstrates
thoracic vertebral bodies
IVD spaces
alignment of pedicles
spinous processes
transverse processes
articular processes
costovertebral joints and posterior ribs
AP thoracic patient position
supine
width between opposing paired pedicles in t-spine
20mm
lateral thoracic spine demonstrates
thoracic vertebral spaces
IVD spaces
intervertebral foramina
uppermost 2-3 vertebrae not well visualized because of superimposition
lateral thoracic patient position
side-lying or upright
most common force of trauma at thoracic spine
flexion forces account for 90% of compression fractures
which vertebrae is most frequently injured?
12th thoracic and 1st lumbar
neuro injury complicates 15-20% of fractures
imaging for trauma of thoracic spine
assessed with thorax-abdomen-pelvis body (TAP) CT scans
can reformat to evaluate spine without additional radiation exposure
is CT or radiograpghs better in detection for spinal fractures
CT
MRI is the primary modality to evaluate …
neural compromise
cord edema
cord contusion
epidural hematoma
nerve root involvement
ligamentous disruption
if the CT is normal, is MRI indicated?
no
what is the most common spinal injury detectable on radiographs in all age groups?
anterior compression fractures
mechanism of injury for older adults in t-spine
pre-existing osteoporosis is a significant factor in vertebral body collapse
why are anterior compression fractures considered stable fractures?
only anterior column is involved
can become unstable if both columns are involved
compression fractures increase in incidence with age due to…
demineralization: bone becomes less elastic, more brittle, more prone to failure
dehydration of nucleus pulpus renders disks less resilient to compression
radiographic signs of compression fractures (6)
step defect: anterior cortex of body first structure to undergo strain and suffer greatest stress. best seen on lateral view.
wedge deformity: collapse of anterior body creates triangular or trapezoidal body. apparent on lateral view. ~30% loss of height required for deformity to be present.
linear zone of impaction: linear band of increased density apparent beneath involved endplate. callus formation in healing fracture
displaced endplates: anterior shearing of IVD may avulse bony rim of endplate or displace it anteriorly. appearance on lateral view.
loss of IVD height: intact disk inferred from well-preserved potential space between vertebrae and proper alignment.
paraspinal edema: paraspinal soft tissue edemas or hematomas often associated with compression fractures. best seen on AP view.
healing of vertebral body fractures
endosteal and periosteal callus formation
union occurs in 3-6 months
anterior height of body rarely returns to normal
mildly damaged disks MAY revascularize and function
normally
treatment of vertebral compression fractures
non-operative is standard of care
pain control and fit patient for thoracolumbar spinal orthosis (TLSO)
~ bracing trunk in extension relieves pain by
unloading anterior vertebral bodies (younger)
~ brace for 4-6 weeks
~ bracing not effective for elderly
when do the most severe symptoms of anterior compression fractures resolve?
10-14 days
osteoporosis
threat for 1/2 americans 55 and older
1 in 2 women and 1 in 4 men will have osteoporosis-related fracture in lifetimes
clinical presentation of vertebral compression fractures
chronic back pain
limited spine mobility
social isolation
existence of one previous vertebral fracture increases risk for subsequent fractures at multiple levels fivefold
generalized osteoporosis anywhere in skeleton demostrates classic radiologic hallmarks of:
increased radiolucency: empty box appearance
cortical thinning
trabecular changes: distinct vertical striations
endplate deformities
smooth indentations seen in endplates centrally
sclerosis along endplates most common in thoracic and lumbar spines
schmorl’s nodes
focal intrusion of nuclear material into vertebral body through structurally weakened endplates results in these radiolucent nodes
what is the primary focus for treatment of vertebral fractures?
pain reduction
anti resorptive meds and bone forming hormones prescribed to slow or reverse bone loss
rehabilitation of vertebral fractures
early stages for improvement of posture and general conditioning
later stages provide adaptive modifications to preserve functional independence in ALD’s and ambulation
scoliosis
lateral deviation of spine from mid-sagittal plane combined with rotational deformities of vertebrae and ribs
pathological changes due to compressive forces on concave side of scoliosis curve:
narrowed disk spaces
wedge-shaped vertebral bodies
shorter/thinner pedicles and laminae
narrowed IVF and spinal canal spaces
pathological changes due to compressive forces on convex side of scoliosis curve:
widened rib spaces
posteriorly positioned rib cage (rib hump)
prevalence of scoliosis
5 degrees: 5% of population
10 degrees: 2-4%
25 degrees: 1.5/1,000 individuals
greater curve, higher female predilection
3-5/1,000 children will develop curves large enough to warrant treatment
three types of idiopathic scoliosis
infantile: before age three, may include neuro
juvenile: ages 3-10, more often girls, high risk for progression
adolescent: age 10 through skeletal maturity, 7:1 female:male ratio. skeletal maturity arrests progression and effectiveness of treatment
four distinct common curve patterns
right thoracic curve: most frequent, T4-T6 to T11-L1, secondary minor curves to compensate keeping eyes horizontal
right thoracolumbar curve: T4-6 to L2-4, can appear to either side, but right more common
left lumbar curve: T11-12 to L5, can appear to either side, but left for common
left lumbar, right thoracic curve: two even curves
radiologic assessment of scoliosis
radiographs most definitive diagnostic modality
determine or rule out etiologies
evaluate curve size, site, flexibility
assess skeletal maturity or bone age
monitor curvature progression or regression
diagnostic radiographic series for scoliosis
erect AP
erect lateral
erect AP lateral flexion views
PA left hand - provide assessment of skeletal age
radiographic indicators of skeletal maturity
fusion of vertebral ring apophyses closely parallels end stages of skeletal maturity (solid union os when maturation is complete)
fusion of iliac crest apophysis to ilium appears at end of skeletal maturity
risser’s sign
process of skeletal maturity as reflected in radiographic appearance of apophyses of iliac crests
apophyses first appear at ASIS and progress over a year’s time to PSIS. fusion completed in an additional 2-3 years
progression assigned Risser’s value from 1+ to 5+
1+ indicates excursion of apophysis over 25% of crest
2+ means 50% of crest is capped
3+ is 75% capped
4+ is 100% capped
5+ indicates osseous fusion is complete
cobb measurement method
gives value for curvature in frontal plane, based on AP view
how to perform cobb method
identify uppermost involved vertebra of curve that tilts significantly toward concavity and draw line along its superior endplate
identify lowermost involved vertebra of curve and draw line along its inferior endplate
draw perpendicular lines through those two lines and measure intersecting angle
treatment choices for adolescent idiopathic scoliosis determined by complex equation that factors in:
skeletal age
curve magnitude
curve location
potential for curve progression
which curve have higher risk for progression
thoracic curves
treatment for scoliosis
minimal magnitude: no active treatment, but close observation
20-40 degrees: spinal bracing combines with exercise until skeletal maturity
curves over 50 degrees: surgical fixation
bracing for scoliosis
most effective in children with significant growth remaining
goal is to stop progression - any correction of curve considered a bonus
surgery to correct scoliosis
posterior spinal fusion with paravertebral rods and bone grafts
goal is to prevent curve progression and diminish spinal deformity
if curve to 50+ degrees at skeletal maturity, progression continues
