Final Flashcards
(144 cards)
1
Q
TD
A
total diseased
2
Q
TND
A
total not diseased
3
Q
FPV
A
false positive
4
Q
FNV
A
false negative
5
Q
TP
A
total positives
6
Q
TN
A
total negatives
7
Q
total positives
A
true positives + false positives
8
Q
total negatives
A
true negatives + false negatives
9
Q
sensitivity
A
true (+) test/ Have disease
TPV/TD
10
Q
how do we catch sensitivity?
A
lesion detection
11
Q
specificity
A
true (-) test/Don’t have disease
TNV/TND
12
Q
positive predictive value
A
true positives/all positives
TPV/TP
13
Q
negative predictive value
A
true negatives/all negatives
TNV/TN
14
Q
accuracy
A
true positives + true negatives/total tests
(TPV+TNV) / TOT
15
Q
looking at benefits and risks, what do medical practices use?
A
benefits over the risks
16
Q
what affects intensity?
A
power and area
17
Q
what are factors of bioeffects?
A
- intensity
- exposure time
18
Q
longer exposure times=
A
increases the risk of damage
19
Q
for bioeffect safety, what must be kept inversely proportional?
A
intesity and exposure time
20
Q
AIUM statement
A
“No independently confirmed adverse effects caused by exposure from present diagnostic ultrasound instruments have been reported in human patients in the absence of contrast agents.”
21
Q
intensity changes dependant on what?
A
location in the beam
22
Q
where is the intensity the stongest?
A
center and focus
23
Q
where is the intensity the weakest?
A
periphery
24
Q
what are variations of intensity?
A
spatial factors
temporal factors
25
what are the spatial factors?
spatial peak
| spatial average
26
spatial peak
intensity at the center
27
spatial average
average of intensities across the beam
28
temportal intesity changes based on what?
moments in time
29
temporal factors
temporal peak
temporal average
pulse average
30
temporal peak
intensity at peak times
31
temporal average
- average intesity across entire pulse period
| - includes dead zone
32
pulse average
- average intensity across entire pulse duration
| - does NOT include dead zone
33
which spatial factor is higher?
spatial peak
34
list temporal factors from higest to lowest
- temporal peak
- pusle average
- temporal average
35
what is the highest out of all factors?
spatial peak
36
what are spatial and temporal factors used in?
research to assess the level of intensity that can cause bioeffects
37
organizations have set standards that ultrasound providers are to adhere to, what are they?
FDA
| AIUM
38
acoustic output statements
maxiumum prescribes intensities
39
acoustic output statements AIUM
“No adverse effects have been observed for an unfocused beam having a SPTA below 100mW/cm2, and focused beam SPTA below 1 W/cm2”
40
acoustic output statements FDA
ISPTA = 720 mW/cm2 (upper limit)
41
what are the differrent intesities?
2D ultrasound-weakest
M-mode
colour doppler
PW spectral-strongest
42
what arre the types of bioeffects?
```
thermal
mechanical (NON-thermal)
```
43
what does ultrasound produce?
heat
44
why would ultrasound heat up tissue?
attenuation
- absorption
- reflection and scattering
45
what does frequency not contribute to?
more intensity coming out of the probe
46
higher frequency sound ________ more
attenuates
47
more of the sound energy will be absorbed within the tissue=
more heat
48
acoustic output intensity
- pulser will decide intensity of outgoing signal
| - can be adjusted using power dial on machine
49
thermal index
measure of how much the particular sound is heating up the tissue
50
what is thermal index most commonly associated with?
SPTA
51
What are the different TI standards depending on the type of tissue being assessed?
TIS-soft tissue
TIC-cranium
TIB-bone
52
AIUM standard soft tissue=
TIS<2
53
AIUM standard bone=
TIB<1.5
54
where is there a higher attenuation?
in bone
55
what adjustments must a sonographer make to maintain ALARA?
- acoutic power
| - exposure time
56
what kind of damage can US do to cells?
sister chromatid exchange
57
what kind of damage can US do to plants?
- chromosomal changes
- growth rate reduction
- cell death
58
what kind of damage can US do to animals?
- fetal weight reduction
- postpartum mortality
- fetal tissue lesions
- hind limb paralysis
- wound repair enhancement
- tumour regression
59
what type of wave is sound?
a pressure wave
| -particles are being pushed againsti other particles
60
mechanical effects
- radiation forces
| - caviation
61
_________ will deform and disrupt objects
shear stresses
62
what can cause flow in a liquid?
shear stresses
63
how many types of caviation are there?
2 types
64
what is cavitation?
production and modification/behaviour of bubbles in a liquid
65
stable cavitation
oscillating bubbles (bigger and smaller)
- produce waves
- shear forces on nearby cells and organelles
66
transient cavitation
oscillating bubbles (bigger and smaller)
- "POP"!
- shock waves
- local high temperature changes
- light emission
67
what is particilarly dangerous in 'gas bodies'?
mechanical effects
68
what are the characterstics of mechanical effects?
- already contain bubbles
| - these micro-explosions hemorrhage lung/intestinal tissue
69
AIUM statement -mechanical effects
“No independently confirmed adverse effects caused by exposure from present diagnostic ultrasound instruments have been reported in human patients in the absence of contrast agents.”
70
how do contrast studies work?
we introduce microbubbles into the patient and ultrasound them
71
when does the risk for mechanical bioeffects become higher?
use of contrast study
72
when is contratt only done?
when benefits outweight the risk
73
AIUM-mechanical index
<1.9 (0.4-1.9)
74
mechanical effects formula
MI=Pr / (f)1/2
75
what is proportional to MI?
peak rarefactional pressure
76
what is inversely proportional to MI?
frequency
77
lower frequencies have higher_______
MI
78
tissue type factor
gas containing tissues will have a higher risk of cavitation
79
what kind of damage does MI have on humans with contrast?
premature ventricular contractions
80
when was X-ray fisrt seen?
1895
81
what is X-ray?
radiation which travels through the air in waves/particles. Some of this radiation can pass through objects, particularly soft-tissues
82
radiopaque
some objects are more dense (bones/calcium deposits/metal) and absorb the radiation not allowing it to pass through
83
radiopaque objects will show up differently than _________ soft tissues, which will allow the radiation through
radiolucent
84
X-ray black
fluid/air
85
X-ray Dark Grey
bowel
86
X-ray White
bone
87
X-ray very white
metal
88
X-ray radiopaque
blocks the x-rays
89
X-ray radiolucent
let the x-rays through
90
what can be correlated from X-ray with ultrasound?
- stones
- constipation (bowel obstruction)
- MSK
- surgical structures
91
what is the X-ray potential for harm?
- accumulation of radiation can result in cell damage that could lead to cancerous conditions
- high levels of radiation exposure can cause radiation burns
92
how is X-rays used in radiation therapy?
x-rays are used to kill malignant cancer cells
93
what are the factors for developing cancer with X-ray?
- exposure time
- age
- Gender (women are more likely)
94
what is fluoroscopy?
X-ray "movie" a constant beam of X-ray passing through the patient
95
what can you assess with fluoroscopy?
- skeletal
- digestive
- urinary
- respiratory
- reproductive systems
96
how does Computed Tomography (CT) work?
uses special x-ray equipment to obtain cross-sectional pictures of the body
97
what does CT display?
detailed images of organs, bones, other tissues
98
what are the uses of CT?
- lesion detection and measurment
- location of lesions and tumors
- can guide biopsy or radiation therapy or surgery
- size determination can be used to see of treament is responding
- contrast agents can be used as well, similar to US to highlight vasculature/lesions
- can be administered orally, intravenously or enema
99
which radiation exposure is higher risk? CT or X-ray?
CT
100
what is the benefit vs risk for CT vs X-ray
eternal struggle
101
what is the risk of CT?
very rare causes can cause allergic reactions
102
what are the symtoms to CT allergic reaction?
- mild itching
- Hives
- shortness of breath
- swelling of throat, face or area of contact
103
what is a newer form of CT?
spiral (or helical) CT scan
104
what is spiral CT?
X-ray machine rotates continuously around the body, following a spiral path to male cross sectional pictures of the body
105
what is better about spiral CT?
- better resolution than CT-better lesion detection
| - faster than CT
106
what is Endoscopy -Colonoscopy/ Esophagogastroduodenoscopy (EGD)?
non-surgical evaluation of digestive tract
107
what does Endoscopy -Colonoscopy/ Esophagogastroduodenoscopy (EGD) involve?
introduction of a small camera into the digestive tract and examination of the walls
108
what can endoscopy detect?
abnormalities and inflammations of the walls
109
what is virtual endoscopy?
virtual endoscopy is a new technique that uses spiral CT/MRI
110
what are endoscopic views constructed from?
3D visualizations taken from the CT/MRI
111
CT colonography or virtual colonoscopy, is under study as a screening technique for __________
colon cancer
112
what is mammography?
form of X-ray used to assess breast tissue for cancer
113
what can mammography catch?
cancer in early stages, often before its palpable
114
does mammography contain radiation?
minimal and considered to be very safe
115
screening mammogram
- patient has no symtoms
| - recommmended annually after age 40
116
diagnostic mammogram
- patient has a new lump, breast pain or changes to breast tissue
- this test is commonly done in conjunction with a breast ultrasound
117
with age, bone mineral density ______
decreases (commonly associated with osteoporosis)
118
what is a bone (mineral) density exam?
measures the amount of calcium within your bones
119
where are the most common areas of reduced BMD?
spine
hip
forearm
120
higher BMD=
less risk for breaking/fracturing a bone
121
is bone density the same as a bone scan?
no
| -this is a nuclear medicine exam that involves injection
122
what is MRI?
creates a very strong magnetic field that aligns the atoms in the body, which are then exposed to RF waves
123
how does a MRI work?
This causes the protons of the atoms to produce a weak signal – “magnetic resonance” – that is picked up by the receiver in the MRI and processed in the computer
124
what are the pros of MRI?
- Completely painless
| - Very high resolution imaging (often the gold standard)
125
what are the cons of MRI?
- Metal implants, pacemakers cannot go near the magnet
- Very, very expensive
- Claustrophobia
126
what is better seen on CT over MRI?
brain bleeding (hemorrhage)
127
when is MRI the gold standard?
- tendon
- ligaments
- spinal cord
- brain infarcts
128
what is angiogrpahy?
Use of contrast agents within the vasculature to assess patent/occluded vessels
129
what can angiography be used with?
X-ray (fluoroscopy)
CT
MRI
130
ECG (electrocardiogram) aka EKG
assessing the electrical activity of the heart
131
stress EKG
ECG monitoring during a stress activity
132
holtor monitoring
involves 24-48 hour ECG
133
radiotracer
Small amounts of radioactive material are placed within the body
134
how is radiotracer inserted into the body?
Radiotracer is either injested or inhaled, and is expected to accumulate in a particular organ (usually within an hour)
135
what happens once the radiotracer is in the organ?
they give off gamma rays which are picked up by special cameras
136
nuclear medicine is ______ tests
functional
137
hot spots
accumulation of radiotracer
138
cold spots
lack thereof
139
positron emission tomography is a form of what?
nuclear medicine
140
what does Positron emission tomography assess?
metabolic activity
141
what studies are PET scanning useful in?
heart
lungs
brain
142
Combined PET/CT
Combination of the two; mapping functionality with the anatomical image (like Duplex Sonography)
143
where is Combined PET/CT usually seen?
in psychological studies, showing brain activity in particular regions of the brain
144
combined PET/CT and cancer
Often cancerous tissue is more active than normal tissue (or may be more blood hungry), so often shows stronger on PET/CT
