Ultrasound

Question 1

WHAT ARW THE BENEFITS OF ULTRASOUND?

Answer 1

Non invasive

Cost effective

No radiation

Accurate

Little patient preparation

Mobile

Question 2

WJAT ARE THE DISADVANTAGES OF ULTRASOUND

Answer 2

Operator dependent

Can be time consuming

Images need to be interpreted

Limited FOV

Cannot image though bowel Gas

Not very specific

Question 3

WHAT ARE THE TUPES OF ULTRASOUND DISPLAY?

Answer 3

B-mode brightness

3D ultrasound

Doppler

Duplex and triplex combinations of mode

Question 4

WHAT IS B MODE?

Answer 4

Grey scale imaging

Maps the strength of the returning beam

Strong reflection = White
Weak reflectors = Grey
No reflection = Black

Question 5

WHAT IS DOPLER?

Answer 5

Used to study blood flow

Direction and velocity

Question 6

KEY CONTROLS IN ULTRASOUND

Answer 6

Power

Depth

Overall gain

Time gain compensation

Focus

Zoom function

Question 7

PATHWAY OF ULTRASOUND IMAGE

Answer 7

Patient

Transducer

Beam former

Receiver

Processor

Display

Question 8

WHAT DO TRANSDUCERS DO?

Answer 8

Converts electrical energy to high
frequency sound waves

This produces pulsed ultrasound beams

Made from piezoelectric materials so able to convert from one energy to another

So can transmit and receive ultrasound

Question 9

WHAT IS THE TRADE OFF BETWEEN RESOLUTION AND DEPTH?

Answer 9

High frequency has good resolution but can not penetrate very deep (12 MHz)

Low frequency can penetrate deep into the body but has a low resolution (3 MHz)

Question 10

WHAT ARE THE DIFFERENT TYPES OF TRANSDUCER?

Answer 10

Curvilinear- 
3-6 MHz
Wide FOV 
Good penetration depth
Low resolution 
E.g Abdomen and obstetrics

Linear 
6-18 MHz
Narrow FOV
Limited penetration depth 
High resolution
E.g head and neck, vascular and MSK

Phased Array 
3-6 MHz
Wide FOV
Good penetration depth 
Limited resolution 
E.g heart

Question 11

EXAMPLES OF PIEZOELECTRIC MATERIALS

Answer 11

Quartz

Lead zircronate Titanate - PZT

Question 12

WHAT IS THE PIEZOELECTRIC EFFECT?

Answer 12

Production of an electric field from applied pressure

Vibrates when applied with a voltage

Generates a voltage when applied with vibration

Question 13

WHAT DOES THE ACOUSTIC LENSE DO?

Answer 13

Focuses the beam to make it narrow

Question 14

WHAT IS THE OVERALL GAIN?

Answer 14

Amplifies the revived echoes across the image

Question 15

WHAT DOWS THE TIME GAIN COMPENSATION (TGC) DO?

Answer 15

Adjusts levels of amplification from different depths