understanding ultrasound physics chapter 11 - display modes

With A-mode, what is displayed on the x-axis?

Depth of the reflector

b-mode:

X-axis = depth Y-axis = none Z-axis = amplitude

With B-mode, which axis is related to the strength of the reflection?

the z-axis is related to reflection strength

in m-mode, what is displayed on the x-axis?

time

A-mode:

x-axis: depth y-axis: amplitude z-axis: none

with a-mode, what is displayed on the y-axis?

Amplitude of the reflected signal

With M-mode, what is displayed on the y-axis?

Depth of the reflector

M-mode

X-axis = time Y-axis = depth Z-axis = none

M-mode (motion mode)

appears as a group of horizontal wavy lines. as a sound pulse is emitted by the transducer, the reflections move at a constant speed from right to left across the screen. various squiggly lines that represent the changing depth of the reflecting surfaces are produced on the screen. a line that moves up and down on the display indicates that a reflector is moving closer to or farther away from the transducer; hence, the name motion mode. the x-axis of an m-mode display represents time. the y axis represents reflector depth, which is derived from the time of flight information of the sound pulse. only mode that provides information about a reflector's changing location with respect to time. of the 3 modes discussed, M-mode is the only one that provides information about a reflector's changing location with respect to time.

B-mode (brightness mode)

appears as a line of dots of varying brightness. -as a sound pulse is emitted by the transducer, an invisible dot moves at a constant speed across the system's display. -when a reflection returns to the transducer, it is processed and the invisible dot is turned on. the brightness of the dot indicates the strength of the reflection; hence the name brightness mode. the x-axis of a b-mode represents reflector depth, which is derived from the time of flight information of the sound pulse. when displayed on an oscilloscope, the amplitude information of a b-mode is routed into the z-axis.

A-mode - amplitude

appears as a series of upward spikes (bigger spike = bigger reflection); the height of the upward deflection is proportional to the amplitude of the returning echo (strong echoes = tall spikes, weak echoes = short spikes); the X-axis (horizontal) represents reflector depth the Y-axis (vertical) represents reflection amplitude a-mode is accurate in determining the depth of reflectors. an a-mode display looks like a big city skyline.

Which mode provides the foundation for real-time, gray scale anatomic imaging?

b-mode, or brightness mode

What is the only display mode that provides information regarding reflector motion with respect to time?

m-mode