imaging midterm Flashcards

1
Q

sensitivity

A

SnNout
negative, out
good for ruling out if test is negative

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2
Q

specificity

A

SpPin
positive, in
good for ruling in if test is positive

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3
Q

potential errors in imaging

A

pt mistaken for another
wrong extremity
less obvious injuries missed
areas of referred pain imaged not area of symptoms
misinterpreted by radiologist
poor quality images

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4
Q

ordering images

A

understand most current standards
evidence base screening
mech of injury and location
brief anatomically correct descriptions
can request priority for routine, serious, life threatening

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5
Q

relevance of pathology

A

comprehensive history and physical examination
radiologist suggests clinical correlation

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6
Q

interpretation

A

interpreting rests primarily with radiologist
skilled review

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7
Q

reflective imaging

A

ultrasound and MRI
energy inserted into system, captured, and converted into and image when returned

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8
Q

ultrasound

A

form mechanical compression of molecules

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9
Q

MRI

A

combination of electromagnetic and radio energy to produce signals from body that can be collected and analyzed to produce an image

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10
Q

ionizing radiation

A

x-rays, CT
require ionizing radiation exposure with attendant risks

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11
Q

CT

A

IR penetrates matter and creates image through computer
hounsfield units- over 2000 levels between black and white

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12
Q

water point in hounsfields

A

negative 1000

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13
Q

air point in hounsfields

A

postive 1000

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14
Q

what is CT good for?

A

bony pathologies

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15
Q

what is MRI good for?

A

soft tissue pathologies

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16
Q

emission imaging

A

bone scan
add radiopharmaceutical agent in blood
shows areas with increased metabolic activity

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17
Q

are bony scans binary

A

yes, give either yes or no answer.
they demonstrate only increased metabolic activity, not the cause

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18
Q

are bone scans diagnostic?

A

no, they are also non-specific

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19
Q

what are bone scans used for

A

injuries to skeleton
degenerative changes
extent of certain metastatic lesions

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20
Q

are bone scans good for fractures?

A

bone scans are time sensitive and positive in case of fractures, such as overuse or stress syndromes

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21
Q

are bone scans expensive?

A

bone scans are more expensive than standard films, but significantly less expensive than CT or MRI

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22
Q

standard x-ray films

A

follows series of analytical steps
requires knowledge of anatomy and spatial relationships
creates bony displacement or reactions such as lesions in surrounding skeletal structures
cost-effective and highly specific for skeletal pathology
ionizing radiation

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23
Q

air density

A

most radiolucent and absorbs least number of particles
darkest portion

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24
Q

fat density

A

considered radiolucent
not as dark as air, but darker than others

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25
fluid density
more absorbent than air or fat intermediate radiolucency
26
bone densities
most dense calcium is metal like density radio-opaque appear white
27
is cortical or cancellous bone more dense
cortical
28
when are shields used?
to protect body parts exposed to radiation that are not of interest in examination
29
what do you use to select views that limit radiation exposure
diagnostic imaging literature
30
what view do use use for scoliosis and why?
PA reduce exposure to breasts and thyroid
31
what are plain radiographs not sensitive to?
early changes in tumors, infections and some fractures subtle pathologies - chance of false negative high
32
where are plain films more specific than bone scans or MRI?
characterizing specific calcification patterns and periosteal reactions
33
number of exposures required for plain
minimum of two taken at 90 degrees to one another cervical and lumbar require 5 each
34
body position relative to source of beam
closer to the plate, the better the resolution will be further from the light source, the more precise resulting shadow
35
overuse of imaging
significant economic problem in US
36
clinical prediction rules
indicate need, help reduce unnecessary imaging
37
basic radiographic principles
do no harm request by DPT written clearly in standard terminology never use x-ray as substitute for taking history and physical correlate history, physical, labs, x-rays to make PT diagnosis avoid repetitious exposure and use shields if fracture indicated, x-ray should be performed include joint above and below suspected pathology lack of x-ray evidence of fracture does not rule out fracture special studies indicated when signs/symptoms do not correlate with x-ray findings soft tissue films can rule out foreign bodies look at both sides frequency of follow up x-rays depends on various factors suspected fractures not seen on initial x-ray should be x-rayed again in 10-14 days include all differential diagnoses to be ruled out or accepted history of neck trauma should have cross-table lateral of c spine to rule out fracture or dislocation before any treatment post-reduction films to judge adequacy and maintenance read on view box with hot light arthrograms have risk of infection or allergic reaction always view fractures with suspicion of pathological etiology only accept quality x-rays
38
orientation of films
check pt name check dates orient on view box by date and sequence check for right and left markers develop a system
39
how does bone react to its environment
just like any other tissue, but in slow motion
40
wolff's law
stressed bone reacts over time by strengthening areas of increased stress and demineralizing or eliminating areas of lowered stress
41
ABCS
alignment bone density and dimension cartilage soft tissue
42
alignment (ABCS)
study size, number, shape, and alignment of bones
43
bone (ABCS)
health of skeletal system interconnected to overall health of organism density and dimension
44
bone density (ABCS)
specific to region and that portion of bone being imaged cancellous bones should have consistent trabecular patterns throughout is periosteum swelling or lifting from bone
45
bone dimensions (ABCS)
specific to anatomic region and bone being evaluated compare both sides
46
cartilage (ABCS)
width and symmetry of joint space cartilage spacer between bony articular surfaces
47
soft tissue (ABCS)
look for swelling, capsular distension, periosteal elevation soft tissue affects structure of musculoskeletal system
48
tomography
slices down to 1mm relatively higher IR but confined to smaller are and has superior resolution to plain radiographs
49
two types of tomography
conventional tomography computed tomography (CT)
50
film and body part stationary while exposed to radiation
plain radiographs
51
CT
tube moves sequential images in parallel planes adjust thickness of slices increased details compared to plain
52
during CT
pt on table moved inside scanning gantry tube rotated 360 degrees around pt relative density values in shades of gray limited differentiation between types of soft tissue excellent definition of bone
53
limitations of CT
less complex and expensive than MRI higher radiation doses and cost to conventional MRI more useful for disc herniations
54
indications of CT
combo of CT and MRI to evaluate combo of bone and soft tissue CT provides additional details of spinal osteophytes and spinal fractures
55
MRI
ability to image both bone and soft tissue uses magnetic fields to produce images
56
MRI physics
magnetic properties of body's tissues exposed to strong radio-frequency pulses that produce measurable changes in body's atoms depend on intrinsic spin of atoms with odd number of neutrons or protons atomic nuclei align to direction of magnetic field RF cause nuclei to absorb energy and produce resonance for type of tissue upon removal of RF energy absorbed is released as electrical signal
57
signal intensity
strength of radio wave that tissue emits following removal of RF
58
bright images
high signal intensity
59
dark images
low signal images
60
image quality
movement can decrease image quality slices too thin or too close produce interference
61
longitudinal or T1 relaxation
return of protons to equilibrium following application and removal of RF pulse fat have bright signal bone bright proteinaceous material medium to bright other soft tissues have normal low T1 weighted clearly delineate soft tissue
62
transverse or T2 relaxation
describes associated loss of coherence or phase between individual protons immediately following application of RF pulse fluids are bright - 2 like H2O overall less details in soft tissue
63
proton density weighted
combine properties of T1 and T2 weighted images and produce good anatomic detail with little tissue contrast
64
fat spin echo (FSE)
T2 weighted produce bright fat fat suppression produces dull fat for contrast to bright fluid second RF rapidly applied FSE T2 reveal marrow pathology
65
inversion recovery (STIR)
reduces signal from fat and increases signal from fluid and edema
66
MRI contraindications
any ferromagnetic metal implants claustrophobia relative high cost
67
MRI indications
high quality images of large joint components 3 orthogonal planes, one suppresses fat FSE or gradient echo should be included intra-articular contrast increases sensitivity to diagnose rotator cuff tears, labral lesions or articular cartilage injuries useful to diagnose muscle and tendon tears superior to ultrasound for monitoring stages of healing
68
scintigraphy (bone scans)
reveal uptake of radiopharmaceutical substance into areas of reactive bone injected hours prior to bone scan reveal areas of radionuclide uptake
69
hot spots
metabolically active areas such as healing have higher uptake appear dark
70
bone scan indications
scan for presence and distribution of lesions help screen for metastasis sensitive but not specific sensitive for changes in fractures, infection, tumors
71
what is the one exceptions to sensitivity of bone scan
multiple myeloma
72
what is multiple myeloma
diffuse osteopenia and multiple lucent areas of bone that result in painful fractures lucent areas represent cold lesions that may not be metabolically active enough to cause increased uptake of radiopharmaceutical on bone scan increased erythrocyte sedimentation rate on plain
73
DPT applications
bone scans to detect stress fractures displaced femoral neck fractures and subsequent AVN of femoral head from unrecognized FHSF
74
stress fracture
MRI with T2 and STIR sequences warranted
75
radionuclide bone scan reveals
old and well healed fractures degenerative joint disease open growth plates sacroiliac joints
76
ultrasound
fast and inexpensive no IR highly sensitive to identification of fine soft tissue changes
77
applications of US
real time muscle contractions tendon gliding muscle size
78
US physics
sound waves differences in signal return provide ability to distinguish structures better images of superficial structures, more useful on thin pts bone and metal reflect sound and cannot be imaged
79
clinical applications of US
excellent for rotator cuff, glenoid labrum hard to see evaluation of hemarthrosis of knee, cannot see menisci, articular cartilage, ACL/PCL early changes in RA acute muscle and tendon injures
80
DPT applications of US
direct operator interaction with pt power doppler very detailed, can demonstrate hyperemia in RC and biceps tendon
81
standard views for glenohumeral joint
ap external rotation ap internal rotation CR perpendicular to 1 inch inferior to coracoid process
82
shoulder distance from glenoid fossa to humeral head
5mm
83
internal rotation
allows to see lesser tuberosity on medial humeral head
84
west point view
used for glenoid rim and relationship of humerus to glenoid pt prone and arm at 90-90 position, beam angled 25 degrees cephalad and 25 degree lateral to medial used for bankart lesions with history of instability acromion superior to glenoid coracoid inferior to glenoid CR through axilla toward AC joint
85
AC joint
tearing of ligaments cause it to shift upward
86
AP view of AC
pt seated beam in ap direction but 15 degrees cephalad CR perpendicular to midline of body at level of AC
87
Weighted AC
weights hung from wrists to depress AC joint without causing muscle stabilization include both affected and unaffected side
88
Scapula views
AP lateral or trans-scapluar
89
AP scapula
CR perpendicular to midscapular area 2 inches inferior to coracoid process
90
lateral scapula
CR perpendicular to mid-lateral border of scapula
91
anterior oblique (Y) scapula
pt 60 degrees anterior oblique position and CR through GH perpendicular to image receptor scapula looks like a Y
92
bankart lesion
anterioinferior aspect of glenoid labrum complication of anterior shoulder dislocation often with hill-sachs lesion
93
hill-sachs lesion
posterolateral humeral head compression fracture anterior shoulder dislocations
94
shoulder osteoarthritis
Loss of joint space Osteophytes Subchondral cysts Subchondral sclerosis
95
standard views of shoulder
AP with hand supinated lateral with hand positioned laterally oblique with hand pronated
96
AP elbow
CR perpendicular to elbow joint elbow straight
97
carrying angle of forearm
longitudinal axes of distal humerus and proximal ulna
98
lateral right elbow
CR perpendicular to elbow elbow at 90 degree angle
99
normal position of capitulum
longitudinal axis of proximal radius passes through center of capitulum anterior border of humerus normally intersects middle 1/3 of capitulum
100
oblique view of elbow
CR perpendicular to arm and enters at elbow joint can see the coronoid process very well
101
standard wrist views
PA lateral semipronated oblique
102
semipronated oblique
evaluation of scaphoid and distal radius
103
special views for wrist
radial and ulnar deviation scaphoid visualization in ulnar deviation
104
PA wrist
CR passes through mid carpal joint
105
three arcuate lines
arc 1 - under proximal row arc 2 - above proximal row arc 3 - under distal row
106
ulnar variance
want ulna and radius level negative when ulna shorter positive when ulna longer
107
radial angle
formed by line perpendicular to long axis and line drawn across radial articular surface should be 15-25 degrees
108
oblique wrist
CR through midcarpal joint hand flat
109
lateral wrist
CR passes through midcarpal joint through lateral side of wrist
110
hand views
PA oblique lateral
111
PA hand
CR perpendicular to hand at 3rd MC joint hand flat
112
radiographic spatial relationships with PA hand
slant through 3-5 MC 2nd MC through center of radius 4th IP above 5th IP
113
boxer's fracture
pinky sometimes 4th finger
114
oblique hand
CR through 3rd MC joint 45 degree foam block used
115
why is a foam block used for oblique hand
elevation of fingers opens MCP and IP
116
lateral hand
CR through 2nd MCP joint through lateral hand
117
terrible triad
dislocation of elbow fracture of radial head fracture of coronoid process
118
radial head fracture classifications
1: non displaced 2: non comminuted, displaced 3: comminuted
119
coronoid fracture classifications
1: avulsion of tip of bone 2: detached fragment of less than 50% 3: detached fragment of more than 50%
120
kienbock disease
osteonecrosis of lunate dominant wrist of young adult men due to repeated loading middle age women equally between dom and non dom with negative ulnar variance
121
scaphoid AVN
~75% arterial supply to scaphoid from branches of radial artery vascular supply to proximal pole is mainly retrograde
122
how many vertebrae total and in each section
total: 33 cervical:7 thoracic: 12 lumbar: 5 sacral: 5 fused coccygeal: 4 fused
123
C1 or Atlas
no vertebral body wrapped around dens of C2 held in place by transverse ligament - prevents anterior displacement of C1 and C2 articular facets more horizontal in AP to facilitate rotation, wedge shaped in ML plane lacks intervertebral disk - decreased shock absorption and stabilization
124
C2 or Axis
projection through C1 odontoid/dens no IVD between it and C1
125
dens fractures
by trauma, congenital malformation, failure to fuse 1: oblique fx through upper 1/3 of odontoid, stable 2: transverse fx through base where it joins to body 3: fx of odontoid down into body
126
lower C spine
C3-C7 size, components, shape, density, dimensions similar compare above and below to each other
127
standard views of c spine
odontoid (open mouth)(APOM) AP left oblique right oblique lateral
128
odontoid
beam directed into the open mouth of pt
129
alignment in APOM
demonstrate odontoid and lateral masses of C1 distance between lateral edges of odontoid and medial edges of lateral masses are symmetrical articular surfaces of C1 and C2 should be parallel
130
jefferson's fracture
lateral overhanging of lateral mass beyond lateral margins of C2
131
offset in C1 and C2
over 2mm is abnormal under 1-2mm can be from head rotation or tilt
132
bone density with APOM
odontoid should have no luncencies
133
AP c spine
pt supine or sitting C3-C7
134
AP c spine alignment
spinous processes make vertical line each segment assess for rotation and tilting
135
comparison of vertebra
vertebra above and below each other within C3-C7 can be compared to assess and changes in density
136
soft tissue AP c spine
dark shadowlike trachea seem in midline may indicate presence of tumor, pneumothorax, or hemothorax
137
pancoat's tumor
white mass in upper lung area displaces trachea
138
left and right oblique C spine
compare both for side by side consistency evaluate IV foramina, pedicles, articular facets
139
lateral view C spine
usually most informative of standard views best viewed after other 4 often supports differential established during review of previous routine views
140
alignment in lateral view of c spine
absence of lordosis, kyphosis, normal lordosis follow anterior and posterior longitudinal ligament and junctions of lamina and spinous processes
141
atlantodens interval (ADI)
must not exceed 3mm any distance above must be evaluated for stability risk factors: trauma, CT/AI disease, congenital disease if at risk, flex/ex studies done before any manual therapy
142
lateral view with flexion (C spine)
pt in full flexion ADI should not widen
143
hangman's fracture
cervical trauma anterior body of C2 overhangs C3 lucency through pedicles of C2 occurs with rapid deceleration and with hyperextension most do not survive
144
anklylosing spondylitis
syndesmophytes bridging anterior vertebral bodies aka bamboo spine uncinate joints in column two
145
rheumatoid arthritis
decreases mineralization of c spine and anterior subluxation
146
soft tissue in lateral view of c spine
decreased density indicative of hemorrhage increased distance between spinous processes may indicate ligament tear
147
what is flattening of the cervical spine an indication of?
cervical spasm
148
in compromise of soft tissue...
... possible to have dislocation of spine without fractures
149
compression fracture
anterior body is not the same height as posterior body
150
variations on normal
absence of space between two bodies may represent HNP or failure of embryonic segmentation block vertebrae, hemivertebrae, transitional vertebrae
151
spina bifida occulta of atlas
absence of spinal laminal line in lateral projection incompletely ossified posterior arch
152
block segments - congenital and acquired
acquired - from pathology or surgery columnar shape congenital - wasp waist, hourglass shaped also could have a mixed block - combo of the two
153
variations of block segments
lack of complete segmentation considered in differential in absence of obvious explanation of pain in atraumatic cases aggressive manual therapy not recommended on non-mobile segment levels found throughout spine