The Basics of Ultrasound

How it works

Sound waves are produced by vibration from the crystal of the probe. They hit tissue and based on wave frequency and tissue properties are altered.

Wave length = Propagation velocity of the tissue / Frequency

Sound waves hit tissues and have one of the above actions. How fast and how intense the sound waves return dictates depth and color. See below for colors types on ultrasound.

ALara

ALARA = As low as reasonably achievable

Limit scan time
Use the lowest power function ( less doppler, appropriate machine presets)
Lowest mechanical index (MI) and thermal index (TI)

IAIM

Indication

Acquire

Interpret

Medical decision-making

Probe motions

the modes

B Mode used for most structural and anatomical questions

M Mode used for motion- pneumothorax (lungs sliding), TAPSE, MAPSE, Fetal Heart Tones (lowest energy), diaphragm excursion

Color doppler used for detection and direction of flow

Power doppler tells you presence of flow but no direction or velocity. Good for low flow states

Pulse wave doppler tells you direction, velocity and phasicity of flow

Tissue doppler is used for tissue compliance. Measures tissue movement

ultrasound ethics

Treat every model as a patient.
Always ask consent.
Inform the model/patient of what you are going to do.
Empower the model/patient to notify you of discomfort.
Clinical Educational scans should only be done with consent and once a confirmatory test has been done.
- Can look at the heart if they just had an echo
- Can look in the abdomen if they just had a CTAP
No billable scans if not credentialled
No scanning alone in the CSEAC unless scanning self
No scanning friends and family
No scanning in sensitive areas

Basic US Slides

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