Ultrasound

Question 1

What is an ultrasound?

Answer 1

The term ‘ultrasound’ applies to all sound waves with a frequency above audible range of human hearing, about 20kHz

Question 2

Acoustic window

Answer 2

Area over which sound waves are applies

Question 3

Acoustic Imedance

Answer 3

The degree of resistance to the passage of ultrasound waves

Question 4

Acoustic interface

Answer 4

The junction between two tissues with different imedances, waves refelcted back as echoa

Question 5

How is an image produced?

Answer 5

1. When probe appllied to patients skin the sound waves pass through soft tissue
2. At acoustic interfaces between organs a percentage of sound waves are reflected back to transducer
3. Returning sound waves lead to deformation of the crystal
4. The change in shape is detcted and converted inyo an electrical signal, turns into image

Question 6

Anechoic

Answer 6

Without and echo - black

Question 7

Hypoechoic

Answer 7

Darker than usual

Question 8

Hyperechoic-

Answer 8

brighter than usual

Question 9

B mode

Answer 9

Brightness mode

Creates 2D image of tissues

Question 10

A mode

Answer 10

Amplitude mode

Simplist form and only shows position of tissues interfaces

Question 11

M mode

Answer 11

Time motion/ movement mode

Question 12

Patient prep

Answer 12

• Clip hair to allow good contact between transducer and skin
• Apply coupling gel
• Cleaning skin with spirit before applying gel can improve image quality