Characteristics of Ultrasound System Flashcards
a single element transducer requires what kind of focusing and steering
mechanical
transducer frequency is ____ to penetration and ____ to resolution
inversely proportional to penetration and directly related to resolution
high frequency transducers have ___ penetration and ___ resolution
poor penetration and improved resolution
what three things are inversely proportional to the transmitted frequency
beam width spatial pulse length and pulse duration
___: usually constructed of 5 concentric ring shaped piezoelectric elements that produce a cylindrical beam
annuar array
annular array has a ___ shaped image
sector
annular array requires what kind of steering
mechanical
circular elements allow for electronic focusing in all planes at all depths providing what
optimal lateral resolution at all depths of the image
___: elements are arranged in a linear pattern
sequential linear array
___: groups of elements are fired at varied times to produce, focus and steer the beam
phased linear array
linear arrays have what kind of focusing
electronic
what kind of focusing and steering does a curved array ahem
electronic
___: contains a large number of linearly arranged rectangular piezoelectric elements
sector phased array
which transducer allows multiple focal points at different depths
sector
narrow sector widths have a lower line density increasing ___ and ___ but decreasing ___
increasing frame rate and temporal resolution but degrading spatial resolution
___: combine a sequence of linear array and phased array techniques to provide a trapezoidal imaging format
vector array
what does DICOM stand for
digital imaging and communication in medicine
what does PACS stand for
picture archival and communication system
what does NAS stand for
network attached storage
what does RIS stand for
radiology information system
what does HIS stand for
hospital information system
harmonic frequency = what
2 times the fundamental frequency
___: scanned lines are electronically stirred by the transducer in different directions to evaluate structures using multiple pulses from several different angles
spatial compounding
what is the only transducer that can use spatial compounding
phased
what kind of resolution is improved with spatial compounding
spatial
what resolution is reduced with spatial compounding
temporal resolution
gain adjusts what
amplitude of returned reflection
___: created uniform brightness from top of image to bottom
TGCs
___: adjusts the brightness of the entire image
gain
focal zones improves ___ at the specific focal depth
spatial resolution
multiple focal zones improve___ but decrease ___
improve lateral resolution but decrease temporal resolution
___: ratio of the smallest to the largest signal strength the system can receive and display properly
dynamic range
the larger the dynamic range the ___ shades of grey on the image
more
dynamic range affects ___ resolution
contrast
___: removes the low level echoes from a 2d image or doppler tracing
rejection
reducing rejection will do what to the image
more shades of grey
increasing depth decreased what
resolution
what frequency transducers have the ability to scan deeper structures
lower
___: number of images displayed per second
frame rate
if from rate decreases what happens to temporal resolution
decreases
___: eliminates low frequency doppler shift from display
wall filter
___: highest velocity in the artery during a cardiac cycle
peak systolic
___: peak flow velocity in the artery at the end of the cardiac cycle
ende diastolic
how do you calculate resistive index
PSV-EDV divided by PSV
the greater the difference between peak and end the higher the ___
RI
how to figure out pulsatility index
PSV - EDV / PSV + EDV
___: the maximum frequency that can be displayed is 1/2 PRF
nyguist limit
what can cause mirror imaging on doppler
over use for doppler gain
