US

Question 1

3 different types of probe

Answer 1

1. linear probe
2. curvilinear probe
3. echo probe (phased array)

Question 2

linear probe

• frequency
• scanning area
• probe of choice for

Answer 2

1. freq: high freq -> maintain resolution, less penetration
2. scanning area: limited to size of probe
3. probe of choice for vascular access, soft tissue and MSK, venous compression studies

Question 3

curvilinear probe

• frequency
• scanning area
• probe of choice for

Answer 3

1. freq: low -> decrease resolution, increased penetration
2. scanning: large area
3. probe of choice for abdominal, retroperitoneal, OB/GYN

Question 4

echo probe

• frequency
• scanning area
• probe of choice for

Answer 4

1. freq: low
2. scanning: smaller than curvilinear
3. probe of choice for cardiac studies

Question 5

attenuation definition

Answer 5

loss of US energy (weakening) as it moves through a medium, resulting in decrease intensity and amplitude

Question 6

attenuation is determined by

Answer 6

frequency of the sound and the distance that the sound wave travels (increase freq and distance -> increase attenuation)

Question 7

attenuation occurs by

Answer 7

1. absorption - primary component of attenuation in soft tissue
2. reflection
3. scattering - if boundary between media is irregular, wave is reflected in a number of different directions (ex: lung tissue)
4. refraction - redirection of part of the sound wave when it crosses from one medium to another (bends the US wave, like when dip pencil in water)

Question 8

impedance definition

Answer 8

how much resistance US beam encounters as it passes through a tissue

Question 9

impedance depends on

Answer 9

1. density of tissue (increase density -> increase impedance)
2. speed of the sound wave

Question 10

common artifacts

Answer 10

1. attenuation shadow
2. scatter
3. ring down
4. acoustic enhancement
5. reverberation
6. mirror image artifact

Question 11

attentuation shadow caused by

Answer 11

region behind dense structure appears dark since few sound wave propagate into and return from that region

Question 12

ring down caused by

Answer 12

fluid trapped between gas bubbles

Question 13

acoustic enhancement caused by

Answer 13

sound wave intensify as it passes through fluid, thus region deep to fluid filled structure appears brighter than surrounding areas

Question 14

reverberation caused by? examples?

Answer 14

1. cause: sound waves bounce back and forth between closely spaced, highly reflective surfaces
2. ex: saline implant, metal needle, comet tails (caused by gas collection along pleura, peritoneum, or bowel wall)

Question 15

mirror image artifact definition

Answer 15

produces false images of adjacent organ (ex: diaphragm and liver)

Question 16

how to tell it is a mirror image

Answer 16

disappear and appear with changes in the position of the transducer

Question 17

septic shock:
cardiac
IVC
aorta

Answer 17

1. hyperdynamic L ventricle, narrow IVC, normal aorta

2. hypodynamic L ventricle in late sepsis, collapse IVC, normal aorta

Question 18

cardiogenic shock:
cardiac
IVC
aorta

Answer 18

cardiac: hypodynamic L ventricle
IVC: normal
aorta: normal

Question 19

hypovolemic shock:
cardiac
IVC
aorta

Answer 19

cardiac: hyperdynamic L ventricle
IVC: narrow/collapse IVC
aorta: ?AAA

Question 20

obstructive shock (cardiac tamponade):
cardiac
IVC
aorta

Answer 20

cardiac: pericardial fluid
IVC: variable
aorta: normal

Question 21

obstructive shock (PE):
cardiac
IVC
aorta

Answer 21

cardiac: dilated R ventricle
IVC: dilated IVC
aorta: normal

Question 22

kidneys

Answer 22

1. medial to liver on the R

2. surrounded by bright capsule and medulla, dark cortex

Question 23

pancreas

Answer 23

1. body lies anterior to splenic vein and SMA

2. head lies anterior to confluence of portal and splenic vein

Question 24

aorta

Answer 24

dark structure in front of bright vertebrae

Question 25

IVC

Answer 25

1. oval structure L of aorta | 2. changes shape depending on respiration

Question 26

bladder

Answer 26

1. uterus posterior to bladder | 2. hypoechoic

Question 27

heart chambers

Answer 27

1. subxiphoid view - R side of heart closer to transducer 2. long axis parasternal view - ventricles 3. short axis parasternal - ventricles and mitral valves 4. apical view - ventricles near transducer, R ventricles small than L ventricles

Question 28

lung/ribs

Answer 28

1. sliding sign 2. A line reverberation, B line reverberation (comet tails) 3. seashore on M-mode 4. pleural line (bright line below the ribs) 5. ribs (dark circles closest to tranducer) 6. mirror image of liver

Question 29

bone

Answer 29

1. periosteum of bone - far field reverberation artifact | 2. seagull sign - formed by articular structures

Question 30

mm

Answer 30

appears dark

Question 31

nerves

Answer 31

honeycomb effect - clusters of dark fasicles surrounded by bright epineurium and perineurium

Question 32

tendon

Answer 32

1. densely packed parallel fibers 2. aisotropy - bright when beam is perpendicular to tendon, dark when beam at acute angle (can be mistaken for vascular structures so use both long and short axis)

Question 33

cholelithiasis/gallstones

Answer 33

stone appears bright with shadow behind it

Question 34

pneumothorax

Answer 34

1. no sliding | 2. bar code sign

Question 35

intraperitoneal free fluid

Answer 35

dark areas in recess 1. hepatorenal recess - dark b/w kidney and liver 2. splenorenal recess - dark b/w kidney and spleen 3. suprapubic recess - dark b/w bladder and uterus

Question 36

flat IVC

Answer 36

completely collapsed, suggest intravascular volume depletion and low central venous pressure