Hemodynamics
Doppler
Artifacts
QA & Sonographers in the Clinical Setting
Bioeffects
100
Blood flowing through the entrance a vessel, all at the same velocity
What is plug flow
100
A disadvantage of continuous wave doppler based on the fact that the exact location of the moving blood cells cannot be determined
What is range ambiguity
100
This artifact is seen when sound interacts with a rounded reflector
What is edge shadowing
100
The minimum distance at which two side-by-side pins are displayed as two distinct images is known as
What is lateral resolution
100
When the thermal index is reported this way, the area of interest should be where in relation to the focal zone
What is at or near
200
Energy lost (or transferred) within the body due to blood cells changing direction
What is inertial loss
200
A low, audible frequency that falls between 20 Hz to 20 kHz
What is the Doppler shift
200
This artifact is seen with weak attenuating reflectors
What is enhancement
200
Ultrasound examination concludes positive appendicitis however the gold standard (CT) shows that the appendix is normal
What is false positive
200
No confirmed bioeffects have been reported for temperature elevations of up to this amount
What is 2 degrees Celsius
300
The form of blood flow that is commonly seen in arteries
What is pulsatile
300
An error commonly seen with Pulsed Wave Doppler when the velocity of the blood cell exceeds the Nyquist limit of the machine and can be fixed with a shallower sample volume
What is aliasing
300
The speed at which an ultrasound system assumes sound is traveling at
What is 1540m/s
300
A test object that simulates scattering, attenuation and velocity properties of soft tissue
What is a tissue equivalent phantom
300
This study technique searches for a relationship between cause and effect
What is mechanistic approach
400
This number used by practitioners predicts whether flow is laminar or turbulent
What is Reynolds number
400
This digital computer-based technique is used to analyze Color Flow Doppler and is substantially faster to perform than other techniques
What is autocorrelation
400
This artifact displays more than 1 reflector on the display
What is crosstalk
400
The study of the interaction between the sonographer, patient and equipment in order to optimize the well being of sonographers in their professional environment
What is ergonomics
400
When considering potential bioeffects, sonographers need to pay closest attention to this during each exam
What is exam duration or exposure time
500
When there is more pressure in the thoracic cavity resulting in a stop or decreases of blood flow coming from the head and arms
What is expiration
500
The vessel labeled SFV in the following image shows blood traveling in what direction
What is right to left
500
Created when sound pulses bounce off a second structure on their way to or from the primary reflector resulting in a distorted replica of anatomy deeper to the true anatomy
What is multipath
500
This poses the greatest risk of potential hazard to our patient due to direct contact
What is the transducer
500
The interaction of sound waves with microscopic, stabilized gas bubbles in the tissues
What is cavitation