Ultrasound

Question 1

What is POCUS

Answer 1

Point of care US: done at bedside to guide the treatment of the patient.

Question 2

POCUS is done to answer a specific question. like what?

Answer 2

is there an effusion

is there gallstones

is there hydronephrosis

Question 3

How does POCUS benefit patients and docs?

Answer 3

improves diagnositc accuracy, while bringing doc to bedside

Question 4

What are advantages of POCUS?

Answer 4

1. No ionizing radiation
2. noninvasive
3. protable
4. easy and FAST
5. immediate feedback
6. not expensive
7. easily repeated, so enhances docs ability to perform serial reassessment

Question 5

What are disadvangtes of POCUS?

Answer 5

1. operator dependent

2. Poor image quality with fat and or air

Question 6

what is the physics of a US probe?

Answer 6

1. US has crystals like quartz.
2. Electrical current causes crystals to vibrate => produce sound/pressure waves
3. Waves travel and hit object
4. Some waves are reflexted back to probe
5. Sound waves hit => create electrical current => converted to image.

Question 7

_____ (Hz) is the number of times/second a wave is generated

Answer 7

frequncy

Question 8

_____ is the distance the wave travels in a single cycle

Answer 8

wavelength

Question 9

how is wavelength & frequency related?

Answer 9

inversely; high frequency = shorter wavelength

Question 10

What type of sounds penetrate more deeply into tissue?

• High frequency/shorter wavelenth
• Low frequency/ longer wavelength

Answer 10

Low frequency/ longer wavelength

Question 11

What kind of probes are best for deep tissue, used to see abdominal structures (aorta, kidney, gallbladder?

What is a downside to this?

Answer 11

Low frequency probes

Bad resolution

Question 12

What kind of probes are best for superficial things (BV, breast tissue and thyroid tissue)

What is a downside to this?

Answer 12

High frequency probes

Poor penetration but GOOD resolution

Question 13

Name the 3 different types of probes.

Answer 13

• 1. Linear (vascular) probe
• 2. Sector or phased array (cardiac) probe
• 3. Curvilinear (curved array or abdominal) probe

Question 14

Linear probe (vascular)

• _________ frequency and resolution
• Used for:
• Pros:

Answer 14

• Higher
• Superficial scanning & procedural guidance
• Lateral resolution is preserved

Question 15

Sector or phased array probe (cardiac)

_________ frequency

Used for:

Pros:

Answer 15

• Lower
• Intercostal scanning bc it has a small footprint
• High frame rates

Question 16

Curvilinear (cuved array or abdominal) probe

_________ frequency

Used for:

Pros:

Answer 16

• Lower frequency
• abdominal
• Large field of view and large footprint

Question 17

US is best for ID’ing what?

Answer 17

1. kidneys
2. liver
3. spleen

Question 18

Besides kidneys, liver and spleen, US can also be used to ID:

Answer 18

heart

aorta

IVC

Bladder

Question 19

Morrisons pouch is on the ____ flank and is a _____ view

Answer 19

Right flank

Hepatorenal view

Question 20

FAST (Focused assessment with sonography for trauma) is used as what?

Answer 20

Quick screening test for trauma patients to detect [intraperitoneal/pericardial/pleural fluid, hemothorax, pneumothorax].

Question 21

IF we find nothing on FAST scan, does that rule out intrabdominal injury?

Answer 21

NOO; has limited sensitivity

Question 22

Where is morrisons pouch located?

whats structures does it include

Answer 22

RUQ at the edge of the lower lateral thoracic cage.

includes: liver, kidney and diapragm

Question 23

Perisplenic view is located on _____

Answer 23

L flank

Question 24

the ability of a structure to reflect sound waves or echoes

Answer 24

echogenicity

Question 25

Structure **does not reflect sound wave**s and appears **black** (**fluid**)

Answer 25

**Anechoic**

Question 26

Structure **reflects very few echoes** and **appear darker** than surrounding tissue

Answer 26

**hypoechoic**

Question 27

echogenic structure; appears brigher than surrounding tissue

Answer 27

**hyperechoic**

Question 28

**common artifact** that occurs when the **sound waves encounter** a **highly reflective surface**

Answer 28

**acoustic shadowing**

Question 29

what appears deep to highly reflective surface that undergoes **acoustic shadowing?**

Answer 29

**Hypoechoic** or **anechoic area**

Question 30

Why are structures deep to highly reflective surfaces in acostic shadowing hypoechoic or anechoic? Give an example

Answer 30

**sound waves cannot get behind or around structure** gall stones

Question 31

What is **posterior acoustic enhancement?** give an example

Answer 31

* **articfact** that occurs when a structure behind an anechoic structure appears very ecogenic/bright because little sound waves are lost traveling though fluid filled structure * Ex. **Bladder**.

Question 32

What is **edge artifact?**

Answer 32

* Sound that is **bent** by a structure in parallel with a US beam and **does not return to the probe**, **creating a shadow** behind the surface.

Question 33

When is an **edge artifact u**sually seen?

Answer 33

1. **fluid fileld structures (GB)** 2. **vessels in transverse imaging**

Question 34

what is a **mirror artififact**

Answer 34

* mirror image of highly refective strucure that is distal to the probe * appears bottom or periphery of screen

Question 35

**Reverbaration artifact** is typically seen with ________ and looks like what?

Answer 35

**line placement** mutuple intermittant echoes that run parallel to needle.

Question 36

What are the **4 cardinal probe movements?**

Answer 36

* **1. Sliding:** slide along skin w/o changing angle * **2. Rocking/heel-toe:** tilt along indicator * **3. Fanning/sweeping:** tilt perpendicular to axis of indicator * **4. Rotating or twisting:** rotate about axis, w/o tilting

Question 37

Diagnostic US has never been shown to harm humans and safe for fetal imaging at all gestational ages. Even then, what do we practice?

Answer 37

**ALARA (as low as resonably acheivable) exposure** to US in *_ANY_* given test

Question 38

Where is the probe marker oriented with **longitudinal scanning**? What about **transverse scanning?**

Answer 38

* to the **head** * to the **patients righ**t, so image will look similar to CT. * **EXCEPT cardiac**, marker is on the **left**

Question 39

what happens if you flip the probe

Answer 39

**flip orientation of screen**

Question 40

where does the concept of ALARA come from?

Answer 40

use of **ionizing radition in CXRs**