SPI Exam Flash Cards Set #2
Digital to analog conversion of the ultrasound signal must occur at what part of the imaging process
between the scan converter and the display
What best describes the mechanistic approach to the study of bioeffects
cause-effect
The most recent digital storage employs what size memory
512 x 512 x 8 bit deep and 256 shades
The principle that states that all points on a wavefront can be considered as point sources for the production of spherical secondary wavelets was postulated by
huygens
A needle or membrane hydrophone is used to measure
pressure amplitude
What is not associated with CW doppler
aliasing
What is necessary additional confirmation required to ensure that the patient you are about to scan is the correct patient
date of birth
With an unfocused transducer, what is the narrowest part of the beam where it starts to diverge called
focus
The lower useful range of diagnostic ultrasound is determined primarily by _____ whereas, the upper useful range is determined by _____
resolution, penetration
Color doppler imaging is a term used to describe
a form of color flow imaging
The greatest doppler angle is achieved
when the beam strikes a vessel as a 30 degree angle
A doppler exam is performed with a 5 MHz transducer. The maximum doppler shift is measured at 2.5 KHz. If the identical exam is performed with a 2.5 MHz transducer, what max doppler shift will be measured
1.25 kHz
Split image artifact is more noticeable in
athletic patients and mesomorphic habitus patients
The frame rate in ultrasound is strongly affected by
imaging depth
What is the most common artifact in doppler ultrasound
aliasing
High frequency transducers have
shorter wavelengths and less penetration
What transducer will exhibit the LEAST amount of volume averaging
1.5D or multi-row array
The frequency of a transducer depends primarily on what
the element thickness
What would not typically be related to ultrasound bioeffects
high frequency transducer
A doppler instrument that can distinguish between positive and negative shifts is called
bidirectional
Reverberation artifacts are a result of
the presence of two or more strong reflecting surfaces
What is the highest amount of output intensity typically utilized in diagnostic ultrasound
pulse wave doppler with real time imaging
A circle of hyperechoic structure is located at a depth of 5cm. The structure has abnormally low attenuation and the speed of sound in the mass is 1400 m/s. What artifact is most likely to appear beneath the structureq
reflections beneath the structure appear abnormally deep in the image
Generally, ultrasound transducers have
better axial resolution than lateral resolution
