TERM 1
DISPLAY MODES
DEFINITION 1
A-mode (Amplitude mode)B-mode (Brightness mode)M-mode
(Motion mode)
TERM 2
A-Mode
DEFINITION 2
Appears as a series of upward spikes.
A-mode is used extensively in ophthalmology, where
accurate measurements of depth or structure thickness
are important.
TERM 3
B-Mode
DEFINITION 3
Returning echoes are displayed as va rious shades of grey
along a single scan line.
The brightness mode appears as a lin e of dots of varying
brightness.
the brightness of the dot indicates th e strength of the
reflection, hence the name brightn ess mode.
The weaker reflections appear as da rker grey dots, whereas
stronger reflections appear as brighte r white dots.
This was the first form of grey scale im aging and is the basis of
all other types of imaging.
TERM 4
M-Mode
DEFINITION 4
Used to evaluate moving structures, such as cardiac
structures.
Appears as a group of horizontal wavy lines.
TERM 5
Display CRT (cathode ray tube)
DEFINITION 5
Located in the narrow end is a gun that shoo ts out a stream of charged
particles called electrons, which contain the video information.
The charged particles fly through electronically controlled, time varying
magnetic fields that focus and snap the elec tron beam across the inside of
the wide end of the tube.
The interior surface of the screen is coated w ith phosphor, which glows when
struck by electrons.
A television image is made up of 525 close ly spaced horizontal lines.
First the electron bean writes the odd numb ered lines 1,3, 5, 7, 9, ... 525.
Tese lines are called the odd field. The entir e field is written in 1/60th of one
second.
Second, the electron beam writes the even numbered lines 2, 4, 6, 8, 10....
524. These lines are called the even field. T he entire field is written in
1/60th of a second.
Therefore, the frame rate of a T.V. display is 30 frames per second or 30 Hz.
