PHYSICS REFRESH

More superficial the imaging

choose the higher within the frequency range

More penetration is needed

lower the frequency

max thermal index

0.7 and mechanical index MI

In this image taken at the 4CH view, the red areas are flowing

towards the probe, meaning into the ventricles. This indicates diastole

The blue flow is going away from the probe which means

blood goes from right atrium to left atrium through the foramen ovale

How to correctly use Color Doppler

The size of the box should just cover area of interest.

Adjust the scale to fit the type of flow you are evaluating.

Adjust color gain so color fills in vessel but does not ‘bleed’ out of the vessel/chamber walls.

PW doppler:

Important for quantifying flow velocity and identifying normal perfusion

Examples: Resistance index, pulsatility index, and S/D ratio important for evaluating normal umbilical artery, uterine artery, and MCA flow patterns

Decrease the scale/PRF

for slower flow or when not sensitive enough

Increase the scale/PRF

when it’s aliasing

What is the purpose of wall filters / high pass filters

Filters LOW FREQUENCY/HIGH AMPLITUDE.

Decrease WF

when not sensitive enough

what angle of insonation is best

0-60 degrees, 0-30 preferred

High velocity flow

High scale

Uterine artery

Umbilical artery

Aorta/MPA/MCA

Low velocity flow

Low scale / Low wall filter

Internal parenchymal flow

R/O ovarian torsion

Eval for polyp/endo vascularity