Real Time B-Mode
provides cinematic view of the area being evaluated by displaying a rapid series of images sequentially
Real Time Imaging
all modern systems use real time approach
signals integrated into a scan converter for 2d image display
Real time movie
Frame Rate
Hz
images per second
2 factors Sound speed in medium
depth of imaging
higher frame rate better temporal resolution and image quality
Temporal resolution
ability to precisely position a moving structure
important in adult and fetal echo
high rate yields better movies but worse photographs
imaging depth
shallow depth incrases frame rate and resolution
deeper decreases frame rate and degrades resolution
depth and frame rate inversely related
operator controlled
Focus
Single Focus
Multi Focus
Single Focus
only 1 sound pulse is transmitted down the scan line
high frame rate
superior resolution
inferior lateral resolution
Multi Focus
Adj number of focus Pulses
longer time
decreases frame rate
inferior temporal resolution
superior lateral resolution
lateral resolution
ability to distinguish between structures that are side by side
sector size
field of view
operator controlled
size increases number of pulses increases
Amplitude Modulation
Distance between transducer and structure determines where an echo is seen along hte time axis
1 dimensional image
Not used anymore
A-Mode
device in which data are represented by variable, measurable, physical quantities. Length, width, voltage or pressure
Analog Scan Converter
2D presentation of echo producing interfaces.
A mode signal converted to dots which vary in brightness depending on echo strength
Brightness Modulation
B-Mode
formation of cavities in a body tissue or an organ resulting from the sudden formation and collapse of low pressure bubbles by means of mechanical forces
Cavitation
image processing device that uses a stable electronic circuit to store and manipulate ultrasonic images in memory. The device then reconstructs and displays these images simultaneously to create one image
Digital Scan Converter
change in observed frequency of a wave. Freq increases as source and observer get closer, decreases as they move apart
Doppler effect
series of shades from black to white the more shades the more realistically an image can be recorded and displayed
Gray Scale Imaging
series of B-Mode dots are displayed on moving time base graph to show moving structures
basis of echocariography prior to real time scanning
used in conjunction with real time imaging in adult, pediatric and fetal echo
M-Mode
Mechanical deformation occurs when an electrical field is applied to a crystal the crystal vibrates mechanically. When a crystal vibrates mechanically it creates an electrical field
Piezoelectric Effect
waves sent from many directions to the returns are used to build a volume image in 3 dimensions
3-D imaging
3-d imaging with the addition of real time
4-D Imaging
sound with freq above the limits of human hearing greater than 20kHz
Ultrasound
Waves that move in an up and down motoin
Transverse Waves
Waves that move in a line
Longitudinal Waves
area of wave that gets closer together
Compression
area of wave that spreads apart
Rarefaction
material through which a wave is transmitted
Medium
period
frequency
amplitude
power
intensity
wavelength
propagation
Accoustic parameters
time
Period of wave
1/time
frequency of wave
