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

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

Basic US Slides