Introduction to POCUS

Question 1

Pros of Ultrasound

Answer 1

• Used for diagnostic and procedural purposes
• No ionizing radiation
• Noninvasive
• Portable
• Relatively easy to use
• Quick
• Immediate feedback
• Inexpensive examinations
• Easily repeated at the bedside, thereby enhancing clinicians ability to perform serial reassessments of patients
• Improve diagnostic accuracy, decreases overall cost of care and decreases time to diagnosis

Question 2

Chest and Abdominal Application of POCUS

Answer 2

• FAST SCAN
• Undifferentiated shock
• Cardiac/lung/aorta/GB/Renal/Urinary retention

Question 3

Chest and Abdominal Applications of POCUS

Answer 3

• FAST SCAN
• Undifferentiated shock
• Cardiac/lung/aorta/GB/renal/urinary retention

Question 4

MSK Applications of POCUS

Answer 4

• Abscess vs induration
• Joint evaluation
• Fractures
• Assess ligaments and tendons
• Foreign bodies

Question 5

Ocular Application of POCUS

Answer 5

Retinal detachment and hemorrhage

Question 6

Procedural Application of POCUS

Answer 6

• Central lines
• Peripheral IVs

Question 7

OB/GYN Application of POCUS

Answer 7

• Fetal well-being/fetal heart tones
• R/o ectopic pregnancy

Question 8

Frequency

Answer 8

• number of times per second a wave is repeated
• expressed as Hertz (Hz)

Question 9

Wavelength

Answer 9

Distance the wave travels in a single cycle

Question 10

Frequency and Wavelength are ____ related

Answer 10

Inversely

Question 11

Relationship of Wavelength and Frequency

Answer 11

• higher the frequency the shorter the wavelength
• high-frequency sound waves have short wavelengths (don’t penetrate deeply into tissue)
• Lower frequency sound waves have longer wavelengths (can penetrate deeply into tissue)
• higher the frequency the better the resolution

Question 12

Linear (Vascular) Probe

Answer 12

• higher frequencies and resolution
• for superficial scanning and procedural guidance
• preserved lateral resolution

Question 13

Sector or Phased Array (Cardiac) Probe

Answer 13

• lower frequencies
• small footprint for intercostal scanning
• high frame rates

Question 14

Curvilinear (Curved Array or Abdominal) Probe

Answer 14

• lowest frequency
• large field of view
• large footprint

Question 15

B-Mode

Answer 15

• “brightness” mode aka “grey scale”
• two-dimensional black and white image with shades of gray in between to indicate the strength of the echo
• default view on most US machines
• most US images are in this mode

Question 16

M-Mode

Answer 16

• “motion” mode
• draws a line on the screen and shows echo profile of every structure along that line (y-axis) over time (x-axis)
• used to demonstrate or measure movement over time in a still image

Question 17

Echogenicity

Answer 17

• ability of a structure to reflect sound waves or echoes
• anechoic vs hypoechoic vs hyperechoic

Question 18

Anechoic

Answer 18

• complete absence of returning sound waves
• appears black (ex. fluid)

Question 19

Hypoechoic

Answer 19

structures that have very echoes and appear darker than the surrounding tissue

Question 20

Hyperechoic

Answer 20

• echogenic structures
• appear brighter than the surrounding tissue

Question 21

Acoustic Shadowing

Answer 21

• common artifact
• occurs when the sound waves encounter a highly reflective surface
• hypoechoic or anechoic area appears deep to the structure
• occurs because very few sound waves can get behind or around the structure
• Ex. gallstones

Question 22

Posterior Acoustic Enhancement

Answer 22

• common artifact
• occurs deep to an anechoic structure
• there is an increase in echogenicity posterior to an anechoic structure because the sound waves lose very little energy traveling through a fluid filled structure
• Ex. bladder (area behind the structure appears very echogenic or bright)

Question 23

Edge Artifact

Answer 23

• sound is refracted (bent) by a structure in parallel with the US beam and does not return to the probe, resulting in the appearance of a shadow behind the surface
• arrowheads show edge artifact from the wall of the gallbladder
• generally seen when imaging fluid filled structures like the gallbladder or vessels in transverse imaging

Question 24

Mirror Artifact

Answer 24

• you see the “mirror image” of the structure being imaged
• it will be distal in relation to the probe
• generally appears at the bottom or periphery of the screen
• highly reflective surfaces cause the machine to display an artifactual image of the reflection of an object

Question 25

Reverberation Artifact

Answer 25

- typically seen with line placement - multiple intermittent lines "echoes" running parallel to the actual needle

Question 26

Gain

Answer 26

- brightness of the US image - the brighter the image the higher the gain and vice versa - adjust this by swiping left or right

Question 27

Longitudinal scanning is with the probe marker:

Answer 27

toward the head

Question 28

Transverse scanning is with the probe marker:

Answer 28

facing the patient's right so that the image will look similar to the orientation of a CT scan --- exception is cardiac where the screen marker is on the left

Question 29

Sliding Technique

Answer 29

Move the probe along the skin without changing angles

Question 30

Rocking (Heel-Toe) Technique

Answer 30

Tilt the probe along the axis of the indicator

Question 31

Fanning (Sweeping) Technique

Answer 31

Tilt the probe perpendicular to the axis of the indicator

Question 32

Rotating Technique

Answer 32

Rotate the probe above the axis of the cord without tilting

Question 33

ALARA (As Low As Reasonably Achievable Exposure) Ultrasound

Answer 33

- concept comes from the use of ionizing radiation in the diagnostic imaging of x-rays - never been shown to harm humans - safe for fetal imaging at all gestational ages as well as adults

Question 34

How do you adjust depth?

Answer 34

by swiping up and down with the probe