Scanning Modes

B-mode or “brightness mode” is used for the majority of PoCUS scans and was described well throughout this text. It produces a two-dimensional cross-sectional slice of the area where the probe is directed. This modality will be used for the majority of your scans.

M-mode– looks at motion over time in a slice of the ultrasound image on the screen. This is plotted as a waveform with time on the x axis and depth on the y axis. M-mode can be helpful in certain instances when looking at moving structures and will be addressed in individual modules when relevant.

Doppler mode relies on the Doppler shift principle of physics:  waves emitted from a source moving towards the transducer will be higher in frequency compared those emitted from a source moving away from the transducer. This frequency shift can be represented by color (red towards, blue away), or by audible/graphical peaks with spectral Doppler. It is important to keep in mind that the color Doppler modes do not discriminate between arteries and veins but rather the direction of the sound waves source. Therefore, you can have situations where arteries are displayed as blue and veins as red. Doppler will be addressed further in individual modules when relevant.