FAST Ultrasound

Question 1

Primary 7 core areas to look at on ultrasound

Answer 1

FAST 
aorta
pelvic
RUQ
cardiac
renal 
procedural

Question 2

What is ultrasound?

Answer 2

mechanical longitudinal wave

Propogates through a medium, interacting with the substance in passes through

Question 3

Wave characteristic of ultrasound

Answer 3

period - seconds per cycle 
frequency - cycles per second 
wavelength - length of complete cycle 
velocity - propogation speed 
amplitude/intensity - height of wave

Question 4

Attentuation of wave propogation

Answer 4

refraction - different propogation speeds
scatter - reflected in multiple directions
absorption - converted to heat

Question 5

Target characteristic of ultrasound

Answer 5

echogenic = bright

anechoic or hypoechoic = dark

Question 6

Function of ultrasound machine

Answer 6

produces mechanical pressure wave through soft tissue
sound moves faster through dense tissues than compressible materials
Transducer produces sound waves and converts them back to electrical signals used to compile images

Question 7

FAST

Answer 7

assesses presence of free intraperitnoeal or pericardial fluid
Acoustic windows are used

Question 8

Advantages of ultrasound

Answer 8

inexpensive
portable
readily available
minimally invasive
no risk to pt
no ionising radiation 
good image of muscle, soft tissue and bone
delineation of solid and fluid filled spaces

Question 9

disadvantages of ultrasound

Answer 9

enhances inflammatory response

can heat soft tissue

Question 10

Limitation of ultrasound

Answer 10

difficulty penetrating bone, and fat
limited by skill of operator
clothing reduces quality of image
small amounts of air preclude effective visualisation