the ability to accurately distinguish two structures lying close together.
What is resolution?
100
longitudinal, Axial ,Range, Radial, Depth
(LARRD)
What is are the synonyms of axial resolution?
100
It is internal focusing,fixed, mechanical or conventional.
What is curved piezoelectric crystal?
100
mm- all units of length.
What are the units of lateral resolution?
100
distance, such as mm.
What is axial and lateral resolution are both measured with units of ?
200
external focusing-with a lens
internal focusing- with a curved active element.
phased array focusing-with the electronics of the ultrasound system.
What is Focusing?
200
No, a new transducer is needed to change LARRD resolution.
Is axial resolution changed by the stenographer?
200
adjustable focusing with the electronics Ultrasound system
What is phased array?
200
the smaller the number for lateral resolution.
What is mean by the more accurate the image.
200
high frequency.
What is (High, Low) frequency transducers have the best range resolution.
300
narrower waist in the ultrasound beam
shallower focus (decreases depth)
smaller focal zone.
how does focusing alter the beam?
300
Low numeric value.
What type of numeric value improves image accuracy for axial resolution??
300
fixed- also called conventional or mechanical
adjustable- by electronics- called phased array (change the focus)
What are the two types of focusing?
300
LATA-
Lateral
Angular
Transverse
What is synonyms of lateral resolution.
300
greater.
If there are more cycles in a pulse, the numerical value of range resolution is
400
mainly in the near and far zone.
where focusing effective?
400
Short
For best axial resolution, the pulse duration (PD) and SPL should be what??
400
external focusing.
What is lens focusing?
400
8/2= 4 this value is one-half the pulse length.
the length of pulse is 8 mm. what is the minimum distance between two reflectors positioned one in from of the other, that still produces two echoes on our image?
400
Shorter pules: better axial resolution
What is the relationship between axial resolution and spatial pulse length?
500
Focusing concentrates the sound energy into a narrower beam and thus improves lateral resolutions.
What is focusing?
500
SPL = wavelength x # of cycles or
SPL = propagation speed/frequency x # of cycles
What are the equations for SPL?
500
diameter of ceramic and frequency of sound.
What is focal length determined by?
500
1. beam diameter in near field and focal zone is reduced.
2. focal depth is shallower.
3. beam diameter in the far zone increases
4. focal zone is smaller.