Test 1 Flashcards
(166 cards)
1
Q
• Examples of ionizing radiation for imaging:
A
X-rays
• Computed Tomography (CT)
• Bone Mineral Density scans (DEXA
2
Q
“Reflective” imaging:Examples
A
Ultrasonography (sound waves)
• MRI (radio frequency waves)
3
Q
Emitted energy imaging examples?
A
radionuclide scans (bone scans, tagged RBC scan)
Thallium scans (functional cardiac imaging)
Positron emission tomography (PET) scan
4
Q
The longer the wavelength the?
A
lower the energy
5
Q
X-rays are generally in the wavelength range of
A
10-9
to 10-11 meters (.1-10 angstroms)
6
Q
The shorter the wavelength, the
A
higher the
energy
7
Q
Air, appears ? on the final x-ray image.
A
black
8
Q
Bone therefore appears ? on the final x-ray image.
A
white
9
Q
Fat is more dense than air, but far less dense than bone, so fat tissue appears
? on the final x-ray
A
dark gray
10
Q
Water, which is the major component of soft tissue is much more dense than air or
fat, but less dense than bone, so water will appear ?
A
whitish gray
11
Q
Substances that absorb x-rays are called
A
radiopaque
12
Q
Radiopaque substances will appear ? on the x-ray images.
A
white
13
Q
Substances that allow more x-rays to pass through are called ?
A
radiolucent
14
Q
• Radiolucent substances will appear ? on the final x-ray images.
A
darker
15
Q
something further away on xray appears
A
larger (magnified)
16
Q
the body part of interest needs to be
A
closest to the film or detector
17
Q
objects closer to the film or detector will be
A
sharper and better defined
18
Q
objects farther away from film or detector will be s
A
blurred, or have less precise edge
19
Q
One structure may obscure another by eliminating contrast at the edges, a
phenomenon called
A
“silhouette sign”
20
Q
• Exposure depends on two things:
A
energy of the x-ray and exposure time
21
Q
higher kVp means higher energy of the x-rays,
A
• Milliamps,(mA): corresponds to the quantity of x-rays produced
22
Q
how to control scatter?
A
KVP, grids, air gap
23
Q
X-rays are excellent tools for
A
Fractures and dislocations
infections
neoplasmsw
24
Q
• Some organs are known to be more sensitive to radiation effects than others:
A
Thyroid • Breast tissue • Gonads and reproductive organs eyes, skin, bone marrow, and vascular structures
25
Lesions involving new bone formation
| • Increased density (radiopaque)
Blastic lesions
Reactive bone from any process
• Reparative phase after a bony injury
26
fracture naming conventions
site (distal, proximal, midshaft
Extent
• Complete, incomplete, comminuted
Type
• spiral, transverse, buckle or torus
•
Alignment and displacement of fracture fragments
* Direction of fracture lines
* Special features
* Associated abnormalities
27
how does cortical bone heal?
• Large hematoma, external callous, fluid matrix, periosteal sleeve
28
how does cancellous bone heal?
• Internal callous, better vascularity usually, faster healing
29
promotes healing?
good immobilization
- growth hormone
- thyroid hormone
- calcitonin
- insulin
- vitamins A&D
- hyaluronidase
- electric currents
- oxygen
- physical exercise
- young age
30
retard healing
- motion
- corticosteroids
- anticoagulants
- anemia
- radiation
- poor blood supply
- infection
- osteoporosis
- osteonecrosis
- comminution
- old age
31
Expected Fracture Healing Times
metacarpal
4-6 wk
32
Expected Fracture Healing Times
metatarsal
4-8 wk
33
Expected Fracture Healing Times
distal radius (extraarticular)
6-8 wk
34
Expected Fracture Healing Times
distal radius (intrarticular)
6-10 wk
35
Expected Fracture Healing Times
humeral shaft
12 wk
36
Expected Fracture Healing Times
femoral shaft
12 wk
37
Expected Fracture Healing Times
radius and ulnar shaft
16 wk
38
Expected Fracture Healing Times
tibial shaft
16-24 wk
39
Expected Fracture Healing Times
femoral neck
24 wk
40
Expected Fracture Healing Times
femoral neck
24 wk
41
Epiphysis remains intact
| • Prognosis is good with treatment
• Salter-Harris Types I and II
42
Epiphysis is injured
• Prognosis is poorer, therefore repair must be more precise to prevent growth
abnormality
• Salter-Harris Types III and IV
43
Crush injury
• Usually occurs along with one of the types I-IV.
• Prognosis poor even with repair.
type V
44
for salter harris injuries the test of choice for diagnosis is?
plain x-ray
45
The biggest advantage of CT over plain radiography is
markedly enhanced detail of
| the final image, especially for soft tissue structures (compared to plain films)
46
• Although ? (see next section) is still the best modality for soft tissues
MRI
47
“Slice thickness” (thickness of the plane that is in focus) can be variable. For most
CT images it is usually between
1-20 mm
48
can detect occult pneumothorax or effusion?
CT
49
CT has to use contrast to see ?
vascular
50
```
Slit length determines the width of the
section to be imaged in relation to the long
axis of the whole part being imaged. In
other words, this determines how wide a
slice through the body is obtained on a
given CT scan.
• Think of it as if the body is being sliced
into pies.
• Slit length determines how thick each
entire pie is.
```
Shorter slit length results in narrower
pies, meaning there is higher
discrimination (you can see the pie
filling better)
51
Slit width determines the size of the slice of
tissue plane imaged with each beam of x-rays.
• In other words, how wide or narrow are the
slices in each pie.
•
Again, smaller width usually means more
detail, because the pie slices are narrower, but
also means more slices per pie (images per
slice) and therefore more radiation exposure
52
(x-ray absorption or transmission) of each pixel is averaged
by the computer from the multiple images that contain the spot that
corresponds to that pixel.
attenuation
53
average attenuation is called the ???, and is
| applied to each of the pixels that make up the final image
"attenuation coefficient"
54
• This is a "grayness" scale that extends from -1000 to +1000
• Hounsfield scale:
55
• ? density is assigned a value of -0-, and defines the midpoint of the scale
Water
56
• ? is the least radiodense substance, and is assigned a value of -1000
Air
57
• Very dense ? is the most dense, and is assigned a value of +1000
bone
58
A bone window, for example, may set water (0 Hounsfield units) as completely
black, and shades of gray for everything above it.
Likewise a lung window may set water (0 Hounsfield units) as completely
white, allowing better grayness discrimination for less dense structures as seen
in the lungs
59
• With contrast, CT is excellent for visualizing details of vascular structures • CT angiography is the test of choice for ?
pulmonary embolus detection
60
Excellent modality for detecting fresh blood in tissue spaces (fresh blood has
an extremely high Hounsfield coefficient, but this decreases as clot formation
progresses )
• Non contrast CT is the test of choice for detecting
intracranial bleeding
61
non contrast CT Also excellent for
soft tissue hematomas
62
non contrast CT Also excellent for
soft tissue hematomas
63
• CT is excellent for observing fine detail in areas with high contrast:
Soft tissue masses in lungs
• Pneumothorax in lungs
• Calcification in muscle or brain, etc..
64
("wobbles") about the axis of its magnetic vector, the way that a
spinning top precesses as it spins
precesses
65
• It must be the EXACT frequency (energy level).
Larmor frequency
66
• This released energy is referred to as their ??, and this can be measured.
echo
67
This return to original state is referred to as
T1
68
which represents the return to
| longitudinal equilibrium with the external magnetic field (parallel/antiparallel)
T1
69
```
When these transverse (xy plane) vectors reach a certain percentage of their
original state (67% to be exact), this is designated as.
```
T2
70
• T2 is far more dependent on the local environment than T1
• T2 is always shorter than T1
71
represents decay from high energy state to low energy state, and is a function
of loss of energy
T1
72
is often referred to as the thermal relaxation time or spin
| lattice relaxation time.
T1
73
though is not a return to a resting energy state, but a loss of phase coherence
between adjacent protons
T2
74
is sometimes called the spin-spin relaxation
| time.
T2
75
time to repetition
| • The time between subsequent RF pulses which are given in sequence
TR=
76
time to echo
| • Time from application of a radiofrequency pulse to peak echo signal
TE
77
• ?? will be longer in tissue that contains more water.
T1
78
?? weighting uses shorter TR and TE, causing tissue with more water to
appear darker, and tissue with less water to appear brighter
T1
79
bone marrow is much whiter on
T2
80
CSF T1?
BLACK
81
CSF T2
WHITE
82
• Fat T1
white
83
Fat T2
black/dark gray
84
CNS gray matter T1
dark gray
85
CNS gray matter T2
light gray
86
Cns white matter T1
light gray
87
Cns white matter t2
dark gray
88
Cns white matter t2
dark gray
89
soft tissue edema t1
dark
90
soft tissue edema t2
light
91
acute stroke t1
dark
92
actue stroke t2
light
93
T1 shows usefulness for?
acute hematoma
fat yellow marrow
lipoma
94
T2 shows useful for
chronic hematoma
fluid/edema
soft tissue tumors
95
bone marrow is seen well on
MRI
96
• This is an imaging technique that can assess function as well as anatomy
PET scan
97
• Usually, Fluorine-18 labeled Fluorodeoxyglucose
PET SCAN
98
is used, usually in conjunction with a CT scan, to detect
metabolically active disorders, such as:
• Cancer or metastases,
• Or to assess metabolic activity of tissue
• CNS in Alzheimer's
• Cardiac blood flow in certain types of ischemic heart disease
pet scan
99
-Sound waves are transmitted through the structure, and not
reflected back to the sound transducer.
• Area will appear black on the image
• Most air or fluid filled structures such as cartilage or joint effusions
anechoic
100
structures with low level echos.
• These appear gray on the final image, and include muscle, synovium,
nerve structures
hypoechoic
101
denser structures that are more reflective of sound waves
• Appear bright or white on the USG image
• Bone, tendon, foreign bodies, areas of calcification
hyperechoic
102
acoustic “void” that appears behind a very reflective object
shadowing
103
Occurs where highly curved surfaces distort or block sound transmission
• Gallbladder, long bone diaphyses, intermuscular interfaces
refractile/critical angle
104
Useful for cyst identification
ultrasound
105
useful for real time vascular imaging
| • Carotid, cardiac, peripheral arteries as well as veins
ultrasound
106
• Real time localization of fluid and abscesses
in ED- cardiac tamponade, pleural effusions, ascites
• in clinic- joint effusions, abscesses
ultrasound
107
Distends joint capsule
• Helps mobilize capsolabral sleeve
• Highlights cartilage defects
Arthrography-
108
• Screening recommended for those with risk factors for osteoporosis
Bone Mineral density imaging
109
Less than 2.5 standard deviations below
mean= high fractures risk, with treatment
recommended
• DEXA: Dual Energy X-ray Absorptiometry
110
• Useful for detecting metastatic cancer and for staging primary tumors
and for fracture age
bone scan
111
Complex regional pain syndrome (RSD)
| • Metabolic bone abnormalities such as Paget disease
bone scan
112
• C1 does not have a vertebral body.
Stabilization of C1 depends on:
• Transverse ligament
• Facet articulations with C2.
113
• There is no intervertebral disk between C1 and C2
• The transverse ligament of C1 is anchored to the odontoid
114
American College of Radiology (ACR) Guideline to the Performance of Spine
Radiography: Indications for imaging:
* Pain or neurologic symptoms
* Spinal trauma
* Surgical planning
* Previous surgery, follow-up or suspected complications
* Neoplastic (benign and malignant) lesions
* Congenital anomalies
* Previously detected abnormality
* Alignment abnormalities
* Infection
* Arthropathy
* Degenerative disorders
* Spine instability or limitation of motion
* Osteoporosis
115
Complete cervical series should include:
| • Routine:
* AP
* Lateral
* Open mouth odontoid views
116
* Complete cervical series should include:
| * Trauma patients:
* AP
* Open mouth odontoid
* Cross-table lateral before moving the patient
* If the spine cannot be adequately examined, obtain CT or MRI
117
c-spine • When assessment of the neural foramina is necessary.
• Bilateral oblique views
118
c-spine• Assessment of the facets, particularly following trauma
• Pillar views
119
c-spine• When assessment of cervical instability is necessary
• Neutral, flexion, and extension lateral views
120
Oblique views are done whenever there is any suspicion for
neuroforaminal
| stenosis
121
With lateral views, it is absolutely necessary to see
| • If not the view is inadequate:
all 7 cervical vertebrae, and the
| superior end plate of T1
122
•??? is usually the image of choice to visualize C7-T1.
A swimmers lateral view
123
??? should be obtained in trauma patients if a swimmers view is not
available or attainable
CT
124
SCIWORA-
Spinal Cord Injury Without Radiographic Abnormality
| • Special case occurring in trauma patients, especially children
125
AP cervical spine films are obtained with patient sitting
| or standing The X-ray beam directed toward
C-4 (about Adam’s
| apple level)
126
AP C-SPINE is used to assess the anteroposterior portion
| of
C3-C7.
127
AP Difficult to assess cartilage on this view,
| ??? is better
lateral
128
hyperextend the neck
| • May occasionally be done when an unobstructed view of the odontoid is absolutely required
Fuchs View
129
usually the most informative cspine
| view
lateral
130
Straightening of the normal lordotic
| curve may indicate ???, associated with occult injury
cervical muscle
| spasm
131
Reversal of the lordotic curve, or
| kyphosis may indicate???
an unstable injury
132
The atlanto-dens interval, ADI, (distance
between the anterior ring of C1 and the
odontoid process) must be no more than ???
3
| mm
133
• A wider ADI indicates ???
C1-C2 instability
134
Look for soft tissue swelling in the retropharyngeal
tissue anterior to C2.
• Normally, the soft tissue in this area is ????
in width.
< 7 mm
135
Similarly, look at the soft tissue in the retrotracheal
space at C6-7
• Normal soft tissue thickness at this level is ???
<22
| mm
136
They are taken with the patient rotated 45
| degrees to the plane of the film/detector
Oblique views
137
• T- spine is a common location for
metastatic cancer
138
standard exams for thoracic spine?
AP
| lateral
139
t-spine lateral view Technique similar to lateral CXR:
| • Patient erect, arms elevated• X-ray focused at ?
T-6 level
140
•lumbar standard examination includes :
• AP and lateral (or PA and lateral)
141
In general clinical practice for most adults, five standard views are usually obtained: l-spine
```
AP
• Lateral
• Right and left obliques
• Cone down sacral view
• Oblique views
```
142
• lumbar AP X-ray beam directed at the ?
mid-abdomen
143
lumbar later view • X-ray beam directed toward
L3
144
Particularly useful for evaluation of the zygoapophyseal joints
• Best views to assess spondylolysis and spondylolisthesis.
oblique
145
oblique view l-spine Side-lying with knees & hips flexed and rotated 45 degrees
• Beam directed toward L3
*only thing that moves is the patient
146
oblique view l-spine Side-lying with knees & hips flexed and rotated 45 degrees
• Beam directed toward L3
*only thing that moves is the patient
147
Scotty dog eyes:
• Pedicles:
148
Scotty dog ears:
superior
149
• Scotty dog legs:
inferior
150
• Scotty dog tail:
superior process,
| opposite side
151
• Scotty dog nose
Transverse process
152
scotty dog neck
par interarticularis
153
scotty dog wearing collar =?
spondylolysis
154
scotty dog decapitated?
spondylolisthesis
155
Sensitivity about 70%/specificity about 90% for fracture, OA and osteonecrosis
of the HIP
CT is much more sensitive for fracture and osteonecrosis (approaching 100%)
156
test of choice to confirm osteonecrosis (specificity ~100%, but sensitivity
only about 38%) of the HIP
MRI
157
American College of Radiography (ACR) recommends the following views for hip?
```
AP
LATERAL (frog leg or true lateral)
```
158
American College of Radiography (ACR) recommends the following views for the pelvis?
AP
159
American College of Radiography (ACR) recommends the following views for the femur?
ap
| lateral
160
• Shows femoral head and neck and greater and lesser trochanters
FROG LEG
161
Inferior lip of the anterior surface of
| acetabulum
radiographic u
162
ilioischial line,
acetabular articular surface, and
radiographic U sign
teardrop
163
Imaginary line formed along the inferior border of the superior pubic rami
(superior border of the obturator foramen) and along the inferomedial
border of the femoral neck
shenton's line
164
Same patient position as AP
• X-ray tube angled about 30
degrees cranially
for the hip?
ferguson view (pelvic inlet)
165
Technique is similar to Ferguson view, but x-ray tube is angled about 60
degrees
pelvic outlet
166
• AP view taken with patient in a 45 degree oblique position of the hip?
Affected hip anterior gives better view of anterior column and posterior
acetabular rim
Affected hip posterior shows better visualization of posterior column and
anterior acetabular rim
judet vidw
