Ch 13 Real-Time Imaging

accuracy in time

temporal resolution

the ability to precisely position moving structures from instant to instant

temporal resolution

temporal resolution is determined by

frame rate

frames per second

frame rate

higher frame rate = better

temporal resolution

frame rate is measured in

Hertz (per second)

frame rate is determined by ____ factors

2

1. speed of sound in medium

2. depth of imaging

factors that determine frame rate

frame rate and time for one frame are ______ related

inversely

frame rate and time for one frame are

reciprocals

time for one frame x frame rate =

1

there are ___ sonographer controlled settings that determine frame rate

2

1. imaging depth

2. number of pulses in each picture

sonographer controlled settings that determine frame rate

imaging depth and frame rate are ______ related

inversely

shallow imaging ______ frame rate

increases

shallow imaging _____ temporal resolution

improves

pulses and frame rate are ______ related

inversely

fewer pulses needed to create an image = ________ frame rate

higher

fewer pulses to create an image ______ temporal resolution

improves

____ factors determine the number of pulses needed to create each image

3

1. number of pulses per scan line

2. sector size

3. lines per angle of sector

factors that determine the number of pulses to create an image

an individual sound beam only has ____ focus

one

with multiple focal zones, _____ pulses are transmitted down each scan line

more

when more pulses are transmitted down each scan line, it causes a _____ in frame rate and degrades temporal resolution

decrease

_____ focusing has a negative impact on temporal resolution

multi

multi-focusing _____ the accuracy of the individual images

improves

with multi focus, each scan line has better _____ resolution because the beam is narrow over a wide range of depths

lateral

when the sonographer expands the sector size, ____ pulses are required to create an image

more

you should _____ your sector width to improve temporal resolution

decrease

the spacing between sound beams

line density

high line density = _______ lines

closely packed

line density and temporal resolution are ________ related

inversely

high line density has a _____ impact on temporal resolution but ______ spatial resolution (overall image detail)

negative , improves

you want better _______ resolution when imaging a moving structure

temporal

you want better ______ resolution when imaging a stationary/still structure

spatial

when PRF decreases, temporal resolution

degrades

for the best temporal resolution you want:

1. _________ imaging

2. ______ focus

3. ______ sector

4. ______ line density

5. _____ frame rate

shallower

single

narrow

low

higher