Adams: Ultrasound

Question 1

Why does longer listening time give you better resolution?

Answer 1

Imagine a cave with an echo
The more you yell the less you can hear reflected back and what you hear back is garbled. (long SPL and short listening phase)
Yell one word and the listen. (short SPL and long listening phase)

Question 2

If higher signal frequencies provide better axial resoluation why not use hte highest freq possible at all times?

Answer 2

less penetration

Question 3

High density

Answer 3

good transmission of sound

Question 4

Low density

Answer 4

poor transmission of sound

Question 5

Bladder

Answer 5

can see wall through water

Question 6

Lung

Answer 6

can’t see well through air, just see artifacts (can diagnose CHF, pneumonia)

Question 7

Flexible

Answer 7

Liver- good transmission of sound

Question 8

Stiff

Answer 8

Bone

poor transmission of sound

Question 9

What is the linear scanning format?

Answer 9

Straight box appearance
probes go straight through

Used for: things w/in 1-2 inches of surface
neck
vein in arm
abscess
central line
testicles
foreign body

HIGH freq so DONT penetrate

Question 10

What is a sector scan?

Answer 10

Low frequency (2-4) BETTER penetration, but lose resolution 
starts close and spreads out

Something father away has to be bigger to be seen

Round footprint, flat footprint

Question 11

What is gain?

Answer 11

controls the amt of brightness on the screen

Question 12

How does a gallstone appear on ultrasound?

Answer 12

hyperechoic (gallstone) leaves a shadow below since most of the ultrasound waves have been reflected

HIGH GRAY SCALE

Question 13

What do you use to measure a cyst in the liver?

Answer 13

medium gray scale

LIVER

Question 14

What is used to ultrasound a fluid filled bladder?

Answer 14

low gray scale–anechoic

Question 15

What mode do you usually use?

Answer 15

B mode

presents real time image

Question 16

When is M mode used?

Answer 16

fetal heart tones

use one beam and measure that beam over time. allows you to see opening and closing of valves. less ultrasound exposure for baby.

Question 17

What is a mirror artifact?

Answer 17

reflection seen when you’re over the diaphragm and the liver

Question 18

Black on an ultrasound is indicative of…

Answer 18

fluid

Question 19

What are the two rules of orientation?

Answer 19

1. the TOP of hte viewing screen is always where the transducer is touching the patient
2. the orientation marker on the transducer and on the viewing screen ALWAYS pt in the same direciton

Question 20

What is ultrasound good for in kids?

Answer 20

diagnosing appendicitis

*should do before CT