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ARDMS SPI 500 QUESTIONS AND
APPROVED ANSWERS.
A sound wave is --Answer-- mechanical, longitudinal A compression area of a sound wave is --Answer-- high pressure, high density A rarefaction area of a sound wave is --Answer-- low pressure, low density Which is considered an acoustic variable --Answer-- pressure Which is a unit for pressure --Answer-- N/m Which is a unit for density --Answer-- lbs/cm Which wave propagates in a medium --Answer-- sound The range for ultrasound is --Answer-- greater than 20KHz ____ is the number of wave cycles per second --Answer-- frequency One kilohertz is equal to --Answer-- 1,000 cycles per second One megahertz is equal to --Answer-- 1,000,000 cycles per second The useful frequency range for clinical imaging ultrasound is --Answer-- 2 MHz to 10 MHz Frequency is determined by the --Answer-- source Frequency affects all of the following, except: wavelength, resolution, penetration, impedance --Answer-- impedance The times per cycle is --Answer-- period
The period for a 5 MHz probe is --Answer-- 0.2usec If frequency increases, period will --Answer-- decreases Period is determined by the --Answer-- source Period multiplied by the number of cycles in a pulse equals --Answer-- pulse duration The distance between cyclical peaks is --Answer-- wavelength The symbol for wavelength is --Answer-- lambda The wavelength of a 5 MHz probe in soft tissue is --Answer-- 0.3 mm As frequency increases, wavelength (assume same medium) --Answer-- decreases Wavelength is determined by the --Answer-- source and medium As wavelength decreases --Answer-- resolution improves The rate at which a sound vibration propagates through a medium is called all of the following, except: sound speed, prop speed, speed of sound, velocity --Answer-- velocity The units for propagation speed include all the following, except: km/sec, mph, msec, mm/sec --Answer-- msec The average speed of sound in soft tissue is --Answer-- 1540 m/sec Arrange the following in increasing order of sound speed in soft tissue -- Answer-- air, fat, muscle, soft tissue, muscle, bone The prop speed of sound of the ceramic lead zirconate titanate (PZT) is approx --Answer-- 4000 m/sec speed of sound is determined by --Answer-- medium The peak variation minus the mean variation is --Answer-- amplitude
Assuming the same area, what effect will an increase in power have on intensity --Answer-- increase What effect will an increase in area have on intensity if power remains unchanged --Answer-- decrease For continuous wave ultrasound, which intensities are equal --Answer-- SPTP, SPTA The factor that describes the spatial intensity distribution across a sound beam is the --Answer-- SP/SA factor The minimum value for the beam uniformity ratio is --Answer-- 1 Ultrasound transducer A has an SP/SA factor of 40. Ultrasound transducer B has a SP/SA factor of 20. Which transducer has the brightest center -- Answer-- transducer A An increase in intensity is determined to be 30 decibels. The intensity is increased by --Answer-- 10 x 10 x 10 or 1, For soft tissue, a 75% loss in intensity can be expressed in decibels as -- Answer-- -6dB The number 1540 may be expressed in scientific notation as --Answer-- 1.540 x 10(-1 power) The number 0.1492 may be written in scientific notation as --Answer-- 1. x 10(-1 power) Arrange the following in the proper increasing order: giga, mega, kilo, hecto, deca --Answer-- deca, hecto, kilo, mega, giga Arrange the following in the proper increasing order: milli, centi, deci, micro, nano --Answer-- deci, centi, milli, micro, nano Arrange the following units of length in increasing order: kilometer, meter, centimeter, micrometer, nanometer --Answer-- micrometer, millimeter, centimeter, meter, kilometer
Which unit would be best to use to express aortic valve area --Answer-- centimeters squared Express the average prop speed of sound in soft tissue --Answer-- 1. mm/usec, 1540 m/sec, 1.54 km/sec The acoustic characteristic of a medium is --Answer-- impedance A reflection will occur at the boundary of two media if the media impedance are --Answer-- dissimilar The percentage of sound energy reflected at a fat/muscle interface is approx --Answer-- 1% The percentage of sound energy reflected at a soft tissue/air interface is approx --Answer-- 50% A reflector that is smooth surfaced and large is called --Answer-- specular examples of specular reflectors --Answer-- mitral valve, interventricular septum, carotid artery Specular reflectors are highly dependent on --Answer-- incident angle Reflectors that are rough surfaced and small are known as --Answer-- scatter Scatter reflectors are highly dependent on --Answer-- transmit frequency The strength of backscatter is dependent upon --Answer-- density, size, impedance Reflectors that reflect ultrasound energy equally in all directions are called -- Answer-- Rayleigh The best example of a scatter reflector is (the) --Answer-- organ parenchyma The best example of of a Rayleigh scatter is the --Answer-- red blood cell
