A-Mode
(Amplitude Mode)
(Amplitude Mode)
- Simplest form of imaging using a single wave emitted from the probe
- Scans a line through the body with echoes plotted as a function of depth
- Rarely used in intensive care or anaesthesia
- Used by ophthalmologists to measure the diameter of the eyeball
B-Mode
(Brightness Mode)
(Brightness Mode)
- The most commonly used mode in anaesthesia and intensive care
- Uses a linear array of transducers to produce a line of ultrasound waves
- Ultrasound scans through a section of tissue and is reflected back producing a two-dimensional view
- The intensity of the image generated is proportional to the intensity of reflected echoes received
- Best image is produced when the reflector is at 90° to the ultrasound beam
M-Mode
(Motion Mode)
(Motion Mode)
- Used to show how a structure moves temporally across a single beam of ultrasound
- Plots a rapid sequence of a-mode images over time
- Often used in cardiac or thoracic scanning to show the movement of structures (e.g. heart valve motion)
Doppler Mode
- Utilizes the doppler effect to detect the direction and velocity of flow
- Colour Flow Doppler: displays the direction and magnitude of flow with colour. Blue indicates flow Away from the ultrasound probe and Red indicates flow Towards the probe (BART)
- Duplex Doppler: combines real time color doppler superimposed onto real-time grey-scale b-mode image