FInal part II Flashcards
Based on the acquisition and review of information from patients or animals exposed to ultrasound
exposure and response
no need to understand mechanism (+ and -)
biological significance is obvious (+)
species differences may alter results (-)
Strongest conclusion are made when the mechanistic and empirical conclusion are in agreement
- Empirical approach
- Contrast, shrinking and swelling
Resonance, nonlinear behavior
- Primary investigative technique of epidemiology
Reviewing data from patients
- Intensity most related to tissue heating
SPTA
- Bioeffect studies on non-living things
Mechanistic Approach
What type of trans causes less amount of temperature increase
Grey scale image Q.# 13, pg 421
- Possibility of patient technologist shock
Mechanical Transducer
- When is it safe to perform in Ultrasound
When the benefits outweight the risk
- Electronic component used for gray scale imaging
Scan converter pg.241
Preprocessing: TGC, log compression, write magnification, persistence spatial compounding, edge enhancement, and fill-in enhancement
- Know all of the preprocessing and post processing functions
- What function steers the scan lines in different directions
Spatial compounding pg.254
Virtually instant
no degradation of data, and the ability to electronically transmit images
report to remote sites (“store and forward”)
- Advantages of PACs systems
- Advantages of PACs systems
Virtually instant
no degradation of data, and the ability to electronically transmit images
report to remote sites (“store and forward”)
Safe metaboliccaly inert long lasting strong reflector of ultrasound small enough to pass through capillaries
- Know the requirements for contrast agents
- Signal from the transducer to the receiver
.?
- Know the requirements for contrast agents
Safe metaboliccaly inert long lasting strong reflector of ultrasound small enough to pass through capillaries
harmonics vs fundamental frequencies
Harmonics is double the fundamental frequency
Harmonics has nonlinear behavior
- Accelerations and deceleration of velocities from cardiac contraction
Pulsitile Flow
Acceleration and deceleration of velocities from respiration
Phasic Flow
change in flow direction increased velocity as vessels narrows turbulence downstream from the stenosis pressure gradient across the stenosis loss of pulsitility
- Know the effects of a stenosis
Supine:
Hydrostatic- 0 mmHg
Blood pressure is same (140 mmHg)
Standing: Hydrostatic -ankle - 100 mmHg - knee - 75 mmHg -waist - 50 mmHg -heart/arm - 0 mmHg - Forehead - -30 mmHg - Tip of finger - -130 mmHg Blood pressure is arterial of heart + hydrostatic
- Know hydrostatic pressure at all locations
- Flow pattern with normal physiological states
Laminar Flow
- Reynolds number for turbulent flow?
Greater than 2,000
- Know the effects of a stenosis
change in flow direction increased velocity as vessels narrows turbulence downstream from the stenosis pressure gradient across the stenosis loss of pulsitility
- Know hydrostatic pressure at all locations
Supine:
Hydrostatic- 0 mmHg
Blood pressure is same (140 mmHg)
Standing: Hydrostatic -ankle - 100 mmHg - knee - 75 mmHg -waist - 50 mmHg -heart/arm - 0 mmHg - Forehead - -30 mmHg - Tip of finger - -130 mmHg Blood pressure is arterial of heart + hydrostatic
- What is it referred to when the vessel collapses venous
coaptation
Baseline lower frequency Shallower volume depth Adjust scale CW
- Five ways to eliminate aliasing
- Venous flow in the leg decreases what is the patient doing?
Inspiration
- Doppler shift when source and receiver are moving apart?
Negative
- What is the typical range of Doppler shift
20 Hz- 20KHz
Audible
- Phenomena of high velocities appear negative
Aliasing
able to select the exact location where velocities are measured
- Primary advantages of pulsed wave
- Five ways to eliminate aliasing
Baseline shift lower frequency transducer Shallower sample volume depth Adjust scale CW
- Know what limitation is for color Doppler imaging
No measurement of velocity or direction.
Lower frame rate.
Susceptible to motion of transducer, patient, or soft tissue- flash artifact.
No measurement of velocity or direction.
Lower frame rate.
Susceptible to motion of transducer, patient, or soft tissue- flash artifact.
- Know what limitation is for color Doppler imaging
- Horizontal axis of a Doppler spectrum
time
- Doppler shift is inversely related to?
Propagation speed
- Basic Doppler system just had just identified a frequency shift
Non- or uni- directional doppler
- Couple questions, just know that traveling towards the transducer and away
Positive when flowing towards the transducer
Negative when it is flowing away from the transducer
- Primary advantages of pulsed wave
Range resolution, range specificity, and freedom from range ambiguity artifact
able to select the exact location where velocities are measured
violation of assumptions
equipment malfunction or poor design
the physics of ultrasound
operator
- Know the cause for artifacts
- Primary advantages of continuous wave
ability to accurately measure very high velocities
- What is the area of interrogation for Doppler
Sample volume or gate
- What method will have increased sensitivity for low flow states
Power mode doppler
- This describes the portions of the image that are brighter than surrounding tissues
Hyperechoic
- Structures without echoes?
Anechoic
- Similar echo chara?
homogenous
- Know the cause for artifacts
violation of assumptions
equipment malfunction or poor design
the physics of ultrasound
operator
- Multiple equally spaced parallel lines what artifact
Reverberation
- Which artifact is unrelated to the US pulse
Enhancement
- Which artifact produces an image with incorrect number of reflectors
Refraction
- Two distinct reflectors one is an artifact one is deeper than the other
Mirror
- What is the artifact if they are side by side
Lateral resolution
Similar to soft tissue
Speed of sound, attenuation, scattering characteristics, echogenicity Pg. 382
- Know about tissue equivalent phantom
- Know about conformed consent
(autonomy)
- Know about gold standard
A perfect technique, for example MRI or angiography, that we deem 100% accurate to which our ultrasound results are compared.
A perfect technique, for example MRI or angiography that we deem 100% accurate to which our ultrasound results are compared.
- Know about gold standard
- Which artifact creates only one reflections with two reflectors
Axial Resolution
- Know the intensity limits for unfocused and focused transducers
Unfocused- 100mW/cm^2
Focused- 1W/cm^2 or 1000mW/cm^2
- Lobes created by array transducers what are they called
grating lobe
- Refraction at the edge of circular structure what is it called
Edge shadowing
- When there is too much gain in the focal zone what is it called
Focal Enhancement
- Which artifact occurs when you see reflectors at incorrect depths
Range ambiguity
- A grainy appearance?
Speckle
- If your PRF is to high what artifact
Range ambiguity
- What artifact found only with Doppler?
Cross talk
- Know about tissue equivalent phantom
Similar to soft tissue
Speed of sound, attenuation, scattering characteristics, echogenicity Pg. 382
- Know about conformed consent
patients are educated about medical procedure(autonomy)
- Ability to position echoes in their correct position along distance perpendicular to the sound
Lateral resolution
- Stratigicle located pins cysts in masses what kind of phantom
Tissue equivalent phantom
- Know the difference of output power and receiver gain
output power effects bioeffects. Receiver gain has no effects on bioeffects. You should always decrease your output power first then adjust your receiver gain.
- Know appropriate way to introduce yourself to the Patient
Tell them your name and what type of exam you are performing
- Know all and what happens to the image and know all the transducers a lot of questions from the transducers
??
- Use of more active elements to receive reflections with a greater time of flight
??
- Know all about temporal spatial and contrast resolution
??
- Lateral resolution improves with what
.?
- Wanted you to figure out the time it takes to make a single image when looking the frame rate, know how to calculation
??
- Imaging depth is 15cm, 100 lines number of pulses making up a scan is what
??
- Know all about component of the US system
??
- TGC curve know the anatomy of that
??
- Of the receiver functions know which one treats the signal differently due to the depth of the reflector
??
- Know the difference of output power and receiver gain
Output power is harmful to bioeffects. Receiver gain isn’t.
If the image is to bright you should always decrease output power first then do receiver gain.
- Know which function will affect the strength of every pulse transmitted into the body
??
- Reflectors displayed only in the far region what would you have to do
??
Any change after freeze frame
black/white inversion
read magnification
contrast variation 3-D rendering
Following question 10. postprocessing
