Chapter 11 Display Modes

Question 1

what imaging mode is
x-axis = time of flight
y-axis = amplitude

Answer 1

A-mode

Question 2

which imaging mode accurately displays reflector depth?

Answer 2

A-mode

it is used in ophthalmology, req precise measures of depth and thickness

Question 3

which imaging mode displays a single jagged line of varying heights

Answer 3

A-mode
x-axis = reflector depth
y-axis = echo amplitude

stronger reflectors=higher spikes= time of flight

Question 4

with B-mode, which axis is the strength of the reflection input?
x
y
z

Answer 4

z- axis

Question 5

which imaging mod places dots of dissimilar gray scale on the display

Answer 5

B-mode

brightness mode

Question 6

The mode that produces lines related to the changing position of reflectors in the body with respect to time is called____

Answer 6

M- mode

is the only display that provides information regarding reflector position in relation to time

Question 7

Which of the following do the x-axis of a B-mod, the y-axis of an M-mod and the x-axis of an A-mode all relate?

Answer 7

x-axis of B-mode & A-mode
y-axis of M-mode ========
REFLECTOR DEPTH
reflector depth is determined by time of flight

Question 8

time of flight is

Answer 8

length of time form pulse creation to pulse reception

directly related to depth

Question 9

depth is calculated by

Answer 9

depth (mm) = 1.54 mm/us * go return time / 2

Question 10

what is 13-microsecond rule?

Answer 10

every 1cm of depth in tissue 13 us of go return time can be calculated

Question 11

with these transducers us beam is STEERED by a motor, a rotating reflecting mirror or a similar device

Answer 11

mechanical tx
annular phased array tx
(mechanical steering)

Question 12

these transducers FOCUS the ultrasound beam electronically

Answer 12

linear switched array
linear phased array
annular phased array
convex or curvilinear array

Question 13

what tx is focused with an acoustic lens, mirror or by milling PZT in a curved shape?

Answer 13

mechanical tx
linear switched array tx
convex or curvilinear tx

acoustic beams can be focused similar to light waves

Question 14

mechanical tx   (t/f)
the ultrasound beam is directed in mamy different directions to create an imaging plane

Answer 14

true
mechanical tx = active element aimed in several directions in order to make 2D image
without steering only a single B-mode line would exist

Question 15

mechanical tx (t/f)
the ultrasound beam is not focused electronically

Answer 15

true
mechanical focusing =
1. acoustic lens
2. curved PZT crystal

Question 16

mechanical tx (t/f)
there is communication between the pulsar of the us system and the piezoelectic crystal of the tx

Answer 16

true

wire is necessary to connect electronic beam former to PZT and send data back to receiver

Question 17

mechanical tx (t/f)
Foci exist @ multiple depths as an us beam propagates through the body

Answer 17

false

mechanical tx = 1 unalterable focal depth

Question 18

which of the following statements are associated with phased array transducers
lens
multi-focused
mirror
adjustable
external

Answer 18

adjustable

multi-focused

Question 19

the minimum number of active elements in a mechanical transducer is

Answer 19

1

imaging plane in constructed by mechanically steering the 1 PZT with a motor

Question 20

which best describes the elements in a linear phased array transducer?
(shape )
(how many)
(and width)

Answer 20

rectangular
100-200 elements
width of 1/4 to 1/2 wavelenght thick

Question 21

t/f

phased array tx direct us pulses in many directions to create a two dimensional image

Answer 21

true

linear curvilinear = electronic steering
annular and phased array = mechanically

Question 22

how are the piezoelectric crystals of a linear phased array tx fired

Answer 22

to steer and focus a linear array PZT are excited by electronic pulse at almost exactly the same time.

Question 23

The pattern of electrical signals exciting the piezoelectric crystals of a linear phased array transducer

typically changes from one acoustic pulse to the next

changes every 4th or 5th acousitic pulse

changes only whenthe max imaging depth changes

none of the above

Answer 23

electrical signal patterns exciting the PZT of a linear phased array tx changes from one pulse to the next
the electrical patterns determine the direction and focusing of ea acoustic pulse. Each sound wave is directed in a slightly diff direction to create a 2D imaging plane
thus the electric signals vary for ea acoustic pulse