Ultrasound

Question 1

What frequency is used in a trans-vaginal ultrasound scan?

Answer 1

6MHz

Question 2

USS assumes that the speed of sound in all tissues is what?

Answer 2

1540m/s

Question 3

Although ultrasound is considered safe, it can still produce biological effects in which three ways?

Answer 3

Cavitation
Micro-steaming
Heating

Question 4

What is meant by cavitation?

Answer 4

Growth and decay of small gas bubbles

Question 5

What is meant by micro-steaming?

Answer 5

Formation of small local fluid circulations

Question 6

What is meant by acoustic impedance?

Answer 6

Resistance of propagation of ultrasound wave

Question 7

Which frequency has better tissue penetration: high or low?

Answer 7

Low frequencies have better tissue penetration

Question 8

Which frequency has better resolution: high or low?

Answer 8

High frequencies have better resolution

Question 9

What information is gained from B mode ultrasound scan?

Answer 9

aka Bright mode

Black and white 2D image used to foetal growth scans etc

Question 10

What information is gained from pulse wave Doppler?

Answer 10

Demonstrates a measurable waveform

Question 11

what information is gained from colour Doppler?

Answer 11

Direction of blood flow
Red is towards the transducer
Blue is away from the transducer

Question 12

What information is gained from Duplex Doppler?

Answer 12

Both colour and pulse wave Doppler

Question 13

What frequency is used in trans-abdominal USS?

Answer 13

3MHz