Ultrasound modes

B-mode, often known as 'brightness mode,' gives structural information in a two-dimensional image by utilizing varying shades of grey (or different 'brightness'). The amplitude of returning echoes determines the brightness

Anechoic/ Echolucent - There are no or very few returning sound waves. Hence the area is dark.

Hypoechoic means the structure has fewer echoes and appears darker than the surrounding tissue.

Hyperechoic/Echogenic - Returning echoes with a large amplitude seem brighter than surrounding tissue.

B-mode

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General Imaging

M-mode (motion mode) captures returning echoes in only one line of the time-lapsed B-mode image.

Structures positioned along that line can now be seen moving.

M-mode and B-mode are frequently presented on the ultrasound monitor in real-time.

M-mode

02

Doppler modes analyze the direction and speed of tissue motion and blood flow and convey the results in auditory, colour, or spectral displays.

Uses a phenomenon known as 'Doppler shift,' which is a change in frequency between the sent and returned sound waves.
These shifts are caused by sound waves striking moving particles.
The frequency shift/change correlates with particle velocity and direction of travel.

Colour Color-flow ultrasound is another name for Doppler ultrasound.

It depicts blood flow or tissue movements in a two-dimensional area of interest.
Colour-coded tissue movements and blood flow directions are placed on the matching B-mode image.
Typically, red represents a movement towards the transducer, and blue represents a movement away from the transducer.

Colour Doppler Mode

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Only the amplitudes of the returning frequency changes are considered by Power Doppler.

It does not investigate flow velocity or flow direction.
This enables the detection of movement at deficient flow levels.
This is useful for assessing vascular crises such as testicular or ovarian torsion.

Power Doppler

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The transducer constantly sends and receives signals.
This enables the detection of extremely high-frequency signals.
Velocities are measured along the full line of interrogation and are not localizable

Spectral Doppler

(Continuous Wave)

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Spectral analysis of pulsed waves The Doppler Transducer transmits ultrasonic pulses to a predetermined depth and then listens for returning echoes to calculate flow velocities at that place.
A typical two-dimensional display shows the "spectrum" of the returning Doppler frequencies.
Venous flow has a more continuous, band-like shape.
The shape of arterial flow is more triangular.