Intro to U/S physics

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Define Frequency

The number of times a wave or cycle is repeated per second

What is wavelength?

It’s the distance travelled by the sound waves in a set amount of time

Velocity is the at which sound travels through a _. (Type out whole sentence)

Velocity is the speed at which sound travels through a medium

Resolution is the ability to ___ two different within a beam. (Type out whole sentence)

Resolution is the ability to differentiate two different structures within a parallel beam Signup and view all the answers

Penetration is how or “” the __ waves can travel. (Type out whole sentence)

Penetration is how far or “deep” the sound waves can travel Signup and view all the answers

High resolution = frequency + _ wavelength

High; short (C) Signup and view all the answers

High penetration = __ frequency + _ wavelength

Low; long (A) Signup and view all the answers

What happens to sound waves as they travel further from the transducer?

They lose strength (attenuate) (C) Signup and view all the answers

What is attenuation in diagnostic imaging?

The loss of strength of sound waves as they travel through a medium (B) Signup and view all the answers

What is refraction in diagnostic imaging?

The bending of sound waves when encountering a change in medium at an oblique angle (C) Signup and view all the answers

When refraction occurs, what effect is produced at the edge of a curved structure?

Shadowing (B) Signup and view all the answers

Refraction is commonly seen in which of the following structures?

Gall bladder, kidney, and cysts (C) Signup and view all the answers

What happens to sound waves during absorption in diagnostic imaging?

They are converted into dissipating heat (B) Signup and view all the answers

What is the primary effect of scattering in ultrasound imaging?

It generates weak echoes due to interaction with small, uneven surfaces (B) Signup and view all the answers

Which ultrasound phenomenon is primarily responsible for creating the appearance of organs on an image?

Reflection (D) Signup and view all the answers

How does reflection contribute to ultrasound imaging?

It produces echoes by bouncing sound waves back to the probe (B) Signup and view all the answers

Which of the following best describes scattering?

The interaction of sound waves with small, uneven surfaces, producing weak echoes (C) Signup and view all the answers

What is acoustic impedance in diagnostic imaging?

The product of tissue density and the velocity of sound within that tissue (D) Signup and view all the answers

What determines how much sound is reflected back to the probe versus how much passes through tissue?

The difference in acoustic impedance between two adjacent tissues (B) Signup and view all the answers

When there is a large difference in acoustic impedance between two adjacent tissues, what happens?

Most of the sound is reflected back to the probe (B) Signup and view all the answers

What tissue pairings would result in a large amount of sound reflection?

Air and bone Signup and view all the answers

What happens when there is little difference in acoustic impedance between two adjacent tissues?

A small amount of sound is reflected, with most passing through (B) Signup and view all the answers

Which of the following situations would result in no sound reflection?

Sound waves traveling between two muscles next to each other (A) Signup and view all the answers

What tissue pairings would result in a little amount of sound reflection?

Fat and organ tissue Signup and view all the answers

What effect does high acoustic impedance have on ultrasound image?

It produces a bright appearance Signup and view all the answers

Which of the following tissues would appear brightest on an ultrasound due to high acoustic impedance?

Bone (C) Signup and view all the answers

What effect does low acoustic impedance have on an ultrasound image?

It produces a dark appearance Signup and view all the answers

What does echogenicity refer to in ultrasound imaging?

The ability of tissues to reflect or transmit ultrasound waves relative to surrounding tissues (B) Signup and view all the answers

What happens when two adjacent structures have different echogenicities

A visible difference in contrast appears on the screen (D) Signup and view all the answers

What does the term anechoic mean in ultrasound imaging?

The structure appears completely black due to no reflection (A) Signup and view all the answers

What structures are typically anechoic on ultrasound?

Pure fluids without cellular content (e.g. cysts, vessels, gallbladder and water) Signup and view all the answers

What does the term hypoechoic mean in ultrasound imaging?

The structure appears darker than surrounding tissues (A) Signup and view all the answers

What does the term hyperechoic mean in ultrasound imaging?

The structure appears brighter (white) than the surrounding structures Signup and view all the answers

What is one example of a hyperechoic structure as discussed in class?

Diaphragm Signup and view all the answers

What is isoechoic?

Two tissues have the same echogenicity Signup and view all the answers

What is an acoustic shadow in ultrasound imaging?

A black or gray artifact caused by a large difference in acoustic impedance (B) Signup and view all the answers

What is a clean acoustic shadow?

A black shadow underneath a structure that reflects a lot of sound (A) Signup and view all the answers

Which of the following would most likely cause a clean acoustic shadow?

A urinary stone in the bladder (B) Signup and view all the answers

What is a dirty acoustic shadow?

A gray shadow caused by sound reflecting back through air with particles (B) Signup and view all the answers

Which of the following would most likely cause a dirty acoustic shadow?

The colon containing gas and particles (C) Signup and view all the answers

What is the primary cause of acoustic enhancement in ultrasound imaging?

Decreased attenuation of sound waves through fluid-filled structures (C) Signup and view all the answers

Which of the following ultrasound artifacts occurs when sound waves are deviated around a round structure?

Edge shadowing/refraction (C) Signup and view all the answers

A veterinarian is performing an ultrasound and notices that the gallbladder appears to have an internal structure that is not actually present. Which artifact is most likely responsible for this false image?

Slice thickness artifact (B) Signup and view all the answers

How can a sonographer correct a slice thickness artifact when it occurs?

Readjust the probe position to change the angle of imaging (C) Signup and view all the answers

Which of the following best describes the mirror image artifact in ultrasound imaging?

A false image created by sound waves being reflected back from the liver to the lung/diaphragm interface before returning to the probe, producing a duplicate structure distal to the actual image (A) Signup and view all the answers

What are the assumptions that are made by the ultrasound machine when generating an image?

Sound waves travel in a straight line, all echoes originate from objects in the beam axis, echoes return to transducer after single reflection, speed of sound in the tissues is constant, the strength of the echoes is directly related to the reflecting/scattering properties of the objects, the depth to the reflecting or scattering object is proportional to the round trip time of the sound wave, and the strength of the sound wave is attenuated evenly Signup and view all the answers

What are the common types of artifacts seen in U/S?

Acoustic shadowing, acoustic enhancement, edge shadowing, slice thickness artifact, mirror image artifact Signup and view all the answers

What is the pulse echo principle?

Sound is emitted 1% of the time, and the transducer listens 99% of the time Signup and view all the answers

What is the primary function of an ultrasound transducer?

To convert sound waves into electrical currents and vice versa (A) Signup and view all the answers

What component within the ultrasound transducer is responsible for generating and detecting sound waves?

Piezoelectric crystals (B) Signup and view all the answers

Why do ultrasound transducers come in different shapes and sizes?

To accommodate different imaging frequencies and anatomical regions (A) Signup and view all the answers

Which type of ultrasound transducer produces a rectangular image and has the highest frequency emission?

Linear transducer (C) Signup and view all the answers

Which of the following statements about a convex transducer is true?

It has low frequency and high penetration, making it useful for general imaging. (C) Signup and view all the answers

Which transducer type is most commonly used for echocardiograms?

Sector transducer (C) Signup and view all the answers

What does the "power" control on an ultrasound machine adjust?

It adjusts the intensity of the sound output from the transducer Signup and view all the answers

What is the purpose/function of absolute gain on the U/S machine?

Manages how intense the sound waves are coming back to the transducer Signup and view all the answers

What is the effect of increasing the absolute gain on an ultrasound image?

It brightens the image (C) Signup and view all the answers

Which ultrasound control compensates for variations in sound wave attenuation at different depths?

Time gain compensation (TGC) (C) Signup and view all the answers

What is the primary function of the focus control on an ultrasound machine?

To create a sharper image at the target organ Signup and view all the answers

Which ultrasound mode is specifically used to record motion over time and is commonly used for echocardiography?

M-mode (B) Signup and view all the answers

In Doppler mode, what does the color blue indicate?

Blood flow moving away from the transducer Signup and view all the answers

In Doppler mode, what does the color red indicate?

Blood flow towards the transducer (BART) Signup and view all the answers

What are the two scanning planes used for U/S?

Dorsal (or saggital) and transverse plane Signup and view all the answers

Each organ should be scanned in only one plane during an ultrasound examination

False (B) Signup and view all the answers

When scanning an organ, you pick a starting point and go in a clockwise fashion

True (A) Signup and view all the answers

Frequency

The number of times a wave or cycle is repeated per second.

Wavelength

The distance travelled by sound waves in a set amount of time.