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chapter one
foundations of sonography
138
Anatomy
Undergraduate 2
06/23/2008

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Term
500 BC Pythagoras
Definition
invented the sonometer. An instrument used to study musical sounds.
Term
1500 AD Leonardo da Vinci
Definition
discovered that sound traveled in waves and that the angle of refraction is equal to the angle of incidence.

 

Term
1638 Galileo
Definition
demonstrated that the frequency of sound waves determined the pitch.
Term
1638 Sir Isaac Newton
Definition
announced the derivation of the theory of velocity.
Term
1638 Robert Boyle
Definition
theory of elastic air
Term
1793 Lazzaro Spallanzani
Definition
Italian priest and scientiest. Theorizes that bats could hear things we could not.
Term
1794 Augustin Fresnel
Definition
Theory of wave diffraction.
Term
1845 Christian Johann Doppler
Definition
discovers the effect of motion on the ptich of sounds. When wave source moves the frequency changes. 
Term
1880 Jacques and Pierre Curie
Definition
piezoelectricity. cyrstals vibrate and convert electrical energy into mechanical.
Term
1890 Lord Rayleigh
Definition
the theory of sound
Term
1900 Paul Langevin
Definition
Studies controlled sound frequency and intensity. property of echoing sound waves to detect underwater objects. SONAR
Term
1938 G.W. Pierce

Floyd Firestone

Definition
Invents the sonic detector. Picks up high frequency vibrations of bats and converts into audible sound.

 

Developes the untrasonic machine call the "Reflectoscope"

Term
1940 Karl Dussik
Definition
used two transducers on opposite sides of the head to measure ultrasound transmission profiles. tumors and intracranial lesions could be detected.
Term
1948 Douglas Howry
Definition
developed the first ultrasound transducer
Term
1948-1950 Howry, Wild, Ludwig
Definition
demonstrated that ultrasound waves by piezoelectric transducer can penetrate body and bounce back. Wave returned were of different accustic impeadence. Measured the fat on hogs to determine when to slaughter.
Term
1950 R.H. Bolt and Ballantyne

Massachusetts Institute of Technology

Definition
use of through transmission and computer analysis to diagnose brain leasions through the intact skull.
Term
1950 Dr. Fry

electrical engineer office of Naval Research during WWII

University of Illinois

Definition
Research used ultrasound to pinpoint lesions within the central nervous system fo animals.
Term
Dr. Myers and Fry
Definition
"pinpoint" lesion technique to treat Parkinson's syndrome
Term
1962 Joseph Holmes
Definition
developed the contact scanner
Term
1965 Dr Lehman of PA
Definition
Used the water path system to scan his obstetric patients. Designed a real-time ultrasound system.
Term

a role

Definition
specific behavior that an individual demonstrates to others
Term
a function
Definition
involves that tasks or duties one is obligated to perform in order to carry out a role.
Term
role of a sonographer
Definition
one who performs ultrasound studies and gathers diagnostic data under the direct or indirect supervision of a physician.
Term
AIUM
Definition
American Institute of Ultrasound in Medicine www.aium.org
Term
ASE
Definition
Amercian Society of Echocardiography www.asecho.org
Term
SDMS
Definition
Society of Diagnostic Medical Sonography www.sdms.org
Term
SVU
Definition

Society of Vascular ultrasound

www.svunet.org

Term
ARDMS
Definition
American Registry of diagnostic medical Sonography www.ardms.org
Term
JRC-DMS
Definition
Joint Review committee on Education in Diagnostic Medical Sonography
Term
JRC-CVT
Definition
Joint Review Commettee on Education in Cardiovascular Technology
Term
JDMS
Definition
Journal of Diagnostic Medical Sonography
Term
JUM
Definition
Journal of Ultrasound in Medicine
Term
JASE
Definition
Journal American Society of Echocardiography
Term
JVU
Definition
Journal for Vascular Ultrasound
Term
anechoic or sonolucent
Definition
without echoes, increased transmission
Term
echogenic or hyperechoic
Definition
echo-producing structure, relects sound, bright structure
Term
enchancement, increased through-transmission
Definition
sound that travels through an anechoic substance and is not attenuated; there is increased brighness directly beyond the posterior border
Term
fluid-fluid level
Definition
interface between who fluids with different acoustic characteristics
Term
heterogeneous
Definition
not uniform in texture
Term
homogeneous
Definition
completely uniform in texture
Term
hypoechoic
Definition
low-level echoes, transmission of sound decreased
Term
infiltrating
Definition
a diffuse disease process or metastatic disease
Term
isoechoic
Definition
very close to the normal parenchyma echogenicity pattern, transmission of sound unchanged
Term
shadowing
Definition
dound beam is attenuated by a solid or calcified object
Term
The border of a structure may be
Definition
smooth/well defined or irregular
Term
The characteristic of an organ or of a mass is said to be
Definition
anechoic, hypoechoic, isoechoic, hyperechoic, echogenic
Term
the transmission of sound is either
Definition
increased, decreased or unchanged.
Term
Cystic
Definition
smooth, well-defined borders, anechoic, increased through-transmission
Term
Complex
Definition
Has characteristics of both cyst and solid structure
Term
Solid
Definition
Irregular borders, internal echoes, decreased through-transmission
Term
Diagnostic applicataion of ultrasound uses frequencies of
Definition
1-10 MHz
Term
compression
Definition
higher frequency, particles closer together
Term
rarefraction
Definition
low frequency, particles farther away
Term
wave
Definition
propagation of energy that moves back and forth or vibrates at a steady rate
Term
ultrasound frequency
Definition
vibrations greater than 20kHz
Term
ultrasound waves are
Definition
mechanical and longitudinal
Term
Pressure (Pa)
Definition

the concentration of force in an area

 

 

 

 

 

 

force / Area

Term
Density (g/cm^3)
Definition

the concentration of mass in a volume

 

 

 

 

 

 

mass(g) / volume (cm^3)

Term
Distance (mm)
Definition

a measure of particle motion cm,mm

 

 

 

 

 

 

Speed * time

Term
Pressure amplitude (Pa)
Definition
the amount of pressure that increases or decreases in the medium as the sound wave travels through
Term
(t) Period (us)
Definition

the time it takes for a wave to complete one cycle

 

 

 

 

 

NO, Source, .1 - .5us

1/f

Term
(f) Frequency (Hz)
Definition

the # of cycles per second.

 

 

 

 

NO, Source, 2 - 10MHz

1/t

Y/c=f

Term
(A) Amplitude (Pa, g/cm^3, mm)
Definition

The strength of a wave measured in decibels. The difference between the max or min value and the average value of an accustic variable

 

 

 YES, Source, 1 - 3MPa

max or min variable value - average or 

max-min / 2

 

Term
(P) Power (W)
Definition

the rate of energy transfer or rate of work performed

 

 

 

 

YES, Source, 4-90mW

P=A^2

Term
(I) Intensity (W/cm^2)
Definition

the concentration of energy in a sound beam. Beams power / cross section area

 

 

 

 

YES, Source, .01 - 300 w/cm^2

I=P(W)/area(cm^2)

Term
(Y) Wavelength (mm)
Definition

the disctance of one cycle.

 

 

 

 

 

NO, Both, .15 - .8mm

Y=c/f (speed/freq)

Term
(C) Propagation speed (m/s) or distance/time units
Definition

the distance a sound wave travels through a medium in 1 sec.

 

 

 

 

NO, Medium, 1500 - 1600m/s

c=Y * f (p.speed=wl*freq)

Term
Pulse
Definition

a set of cycles that travel together

 

 

 

 

 

 

Term
(PD) Pluse duration (us) or (ms,sec units of time)
Definition

the amount of time it takes to complete one cycle. actual time from start to end of a pulse. "on time"

 

 

 

 

NO, source, .5 - 3.0 us

#of cyc * t or #of cyc/f 

 

Term
(PRP) Pulse repetition period (us) units of time
Definition

time from the start of a pulse to the start of the next pulse. on time plus listening time. (temporal resolution, movie)

 

 

 

YES, Depth affected, 0.1 - 1.0ms

1/PRF (kHz)

Term
(PRF) Pulse repetition frequency (kHz) or per sec
Definition

the number of pulses per sec.

 

 

 

 

 

 YES, Depth affected, 1-10kHz

1/PRP (ms)

Term
(SPL) Spatial pulse length (mm) units of distance
Definition

the distance occupied by one pulse. (image resolution)

 

 

 

 

NO, Both, 0.1 - 1.0mm

#of cyc * wavelength(mm)

Term
(DF) Duty factor (%)
Definition

% or fraction of time the system is transmitting a pulse.

 

 

 

 

YES, Depth affected, .2% - .5%

PD/PRP x 100

Term
two components of a single cycle of sound
Definition
compressions, rarfractions
Term
two components of pulsed sound
Definition

transmit, send or on time, 

receive, listening or off time.

Term
normal pulse rate
Definition
60-100 beats/min, count for 10 seconds x 6 = beats/min
Term
normal respiration rate
Definition
16-20 breaths/min. count breaths for 15 sec x 4.
Term
normal blood pressure
Definition
100-130mmHg / 60-80mmHg
systolic(contraction)/diastolic (rest)
Term
acustic impedance
Definition
measure of a meterial's resistance to the propagation of sound. Density of tissue times the speed of sound in tissue
Term
crystal
Definition
material within the transducer that converts electrical impulses into sound waves and vice versa
Term
average speed of sound through tissue
Definition
1540 m/s
Term
simple cyst
Definition
smooth borders, anechoic, increased transmission
Term
hypoechoic mass
Definition
few to low-level internal echoes, smooth border, no increase transmission
Term
complicated cyst
Definition
mixed pattern of cystic and solid, fluid, debris, blood, transmission may or may not increase
Term
lobulated cyst
Definition
well defined with thin septa, increased transmission
Term
loculated cyst
Definition
well defined with thick septa
Term
abcess
Definition
may have irregular borders, debris within, transmission may or may not be increased
Term
homogeneous mass
Definition
uniform testure within
Term
heterogeneous mass
Definition
nonuniform texture within
Term
infiltrating mass
Definition
distorted architecture, irregular borders, decreased transmission
Term
frequency of infrasound
Definition
0-25 Hz
Term
frequency of audible sound
Definition
20Hz - 20kHZ
Term
frequency of ultrasonic waves 
Definition
> 20kHz
Term
the transducer converts
Definition
electrical energy to mechanical energy
Term
the returning signal of a sound beam is weaker than the intial impulse due to...
Definition
reflection, absorption, and scatter
Term
Piezoelectric effect
Definition
piezoelectric cystals capable of converting electrical energy to mechanical
Term
attenuation
Definition
reduction in the amplitude and intensity of a sound wave as it propagates through a medium.
Term
angle of incidence
Definition
angle at which the sound beam strikes the interface
Term
angle of reflection
Definition
angle at which the beam of the sound is reflected from an interface. = angle of incidence
Term
Fresnel zone
Definition
near field, area closest to the face of the transducer. the frequency and diameter determine the length of the near field.
Term
Fraunhofer zone
Definition
far field, area farther from the transducer
Term
Focal zone
Definition
sharpest imagery point of the transducer
Term
spatial resolution
Definition
the minimum distance between two objects where they can be displayed as seperate structures
Term
lateral resolution
Definition
minimum distance between two object positioned along the line perpendicular to the beam
Term
Axial resolution
Definition
minimum distance between two structures positioned along the axis of the beam. (axial resolution = 1/2 spatial pulse length)
Term
typical values for spatial resolution
Definition

axial 0.1mm-1mm

lateral 1.0mm-5mm

slice thickness 2.0mm-12mm

Term
linear array transducer
Definition
multiple small transducer elements electronically coordinated to produce a rectangular image
Term
curved array
Definition
linear array transducer with a curved scan head and electronic focusing to produce a trapezoidal, rectangular image
Term
sector array
Definition
small transducer head with multiple pinpoint elements that produces a pie-shaped image
Term
Endorectal transducer
Definition
special transducer that is introduced in the rectum to examine the prostate, bladder and rectum
Term
endovaginal transducer
Definition
high frequency probe that is inserted into the vagina to image uterus, ovaries and adnexal area
Term
high frequency transducers are used for smaller structures such as...
Definition
carotid artery, thyroidm, scrotum, breast
Term
the abdomen is usually scanned with what type of transducer
Definition
curved linear array or sector array
Term
transducer used for scanning between ribs for a echocardiographic exam
Definition
sector
Term
transducer used for obstetric and gynecologic scans
Definition
linear or curved
Term
A-mode (amplitude modulation)
Definition
one dimensional image, displays the amplitude strength of the returning echo signal along the vertical axis and time and distance along horizontal. the greater the reflection at the interface, the taller the amplitude spike will appear
Term
B-Mode (brightness)
Definition
Method of displaying the intensity (amplitude) of an echo by varying the brightness of a dot to correspond to echo strength. the basis for all real-time imaging
Term
gray scale
Definition
the condition of assigning each level of amplitude a particular shad of gray.
Term
M-mode (motion mode)
Definition

displays time along the horizontal axis and depth along the vertical axis. used to depict movement, especially in cardiac structures

Term
Real time imaging
Definition
provides a dynamic presentation of multiple image frames per second over selected areas of the body.
Term
temporal resolution
Definition
the ability of the system to accurately dipict motion
Term
three dimensional reconstruction
Definition
images are acquired on the x,y,z axis manually re-aligned and then reconstructed into a 3d format. fetal face in 2 or 3 trimester
Term
doppler effect
Definition
the change in frequency of a sound wave then either the source or the listener is moving relative to one another. used for laminar or turbulent flow detection
Term
laminar flow
Definition
smooth uniform velocity
Term
turbulent flow
Definition
multiple flow velocity
Term
continuous wave doppler
Definition
two piezoelectric elements one for sending one for receiving. continuous transmission. 100% duty factor
Term
pulse wave doppler
Definition
slower flows and has one crystal that pulses to transmit. listens and sends signal. duty factor usually less than 1%.
Term
doppler angle
Definition
angle that the reflector path makes with the untrasound beam. the closer the doppler is to zero the more accurate the flow velocity. thus more parallel the transducer is to flow the more accurate the velocity.
Term
artifacts
Definition
structures of an image that do not correspond to the object being imaged.
Term
equipment artifacts
Definition

1. artificial noise (plug)

2. absence of focusing

3. grating lobes (echoes travel at an angle to the main beam

4. side lobes (secondary echoes outside main beam)

Term
technique artifacts
Definition

1. noise caused by excess gain

(decrease gain, adjust TGC)

 

2. Banding caused by finely focused transduces or inaccurate TGC settings.

(change transducer/or TGC)

Term
movement artifacts
Definition
breathing (patient must hold breath)
Term
shadowing artifact
Definition

caused when sound strikes a strong interface gas or bowel.

 

solution:change to a higher frequency transducer, compress tissue gently to displace shadow, roll patient

Term
reverberation artifact
Definition

caused by sound passing out a structure with acustic impedance that is markedly different from its neighbor causing a large amount of sound returned to the transducer. transducer placement over ribs.

 solution: try different acoustic windows, rotate patient, change frequency of transducer

Term
mirror artifact
Definition

occurs is a structure has a curved surface (liver/diaphragm)

 

solution:scan patient from another position

Term
enchancement artifact
Definition

occurs when sound passses easily through an anechoic fluid-filled structure, without attenuation. bright echos posterior to structure.

 

solution:diminish the overall gain or slightly adjust the TGC, change to a higher frequency transducer

Term
slice thickness artifact
Definition

caused when an interface between a fluid-filled cyst and soft tissue is acutely angled and the beam strikes both the tissue and the fluid simultaneously. (gallbladder and cyst adjacent to one another)

 

solution:scan from a different angle

Term
comet effect artifact
Definition

strong acustical interface from an air-bubble or metalliic cuture.

 

solution: scan from a different angle or rotate patient

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