Adams: Ultrasound Flashcards Preview

GI- Week 3 > Adams: Ultrasound > Flashcards

Flashcards in Adams: Ultrasound Deck (20):
1

Why does longer listening time give you better resolution?

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)

2

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

less penetration

3

High density

good transmission of sound

4

Low density

poor transmission of sound

5

Bladder

can see wall through water

6

Lung

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

7

Flexible

Liver- good transmission of sound

8

Stiff

Bone
poor transmission of sound

9

What is the linear scanning format?

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

10

What is a sector scan?

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

11

What is gain?

controls the amt of brightness on the screen

12

How does a gallstone appear on ultrasound?

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


HIGH GRAY SCALE

13

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

medium gray scale
LIVER

14

What is used to ultrasound a fluid filled bladder?

low gray scale--anechoic

15

What mode do you usually use?

B mode
presents real time image

16

When is M mode used?

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.

17

What is a mirror artifact?

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

18

Black on an ultrasound is indicative of...

fluid

19

What are the two rules of orientation?

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

20

What is ultrasound good for in kids?

diagnosing appendicitis

*should do before CT