Ultrasound Imaging Modes

Questions and Answers

Measuring the depth of structures

The time it takes for the echo to return

1540 m/sec

Echo encephalography Signup and view all the answers

> 3 mm Signup and view all the answers

Corneal curvature Signup and view all the answers

Because the eye has a smaller absorption area Signup and view all the answers

B-mode Signup and view all the answers

The use of moving transducers and formation of 2D images Signup and view all the answers

Corneal curvature Signup and view all the answers

Study Notes

Used to obtain diagnostic information about the depth of structures (image with 1 dimension)
US waves sent into the body, measuring time required to receive reflected sound (echoes) from interfaces between different tissues
Depth of interface recorded is proportional to time it takes for echo to return: Depth = Velocity × time
In average soft tissue, sound velocity is 1540 m/sec, and echo takes 13 µsec at a depth of 1 cm
Applications: detection of brain tumors and eye diseases

Used to detect brain tumors
Pulses of ultrasound sent to a thin region of the skull above the ear
Echoes from different structures displayed on oscilloscope
Compare echoes from left and right sides of head to find shift in middle structure:
- Shift > 3 mm for an adult (abnormal)
- Shift > 2 mm for a child (abnormal)

Used in diagnosis of eye diseases and biometry (measuring distances in the eye)
Ultrasound frequencies up to 20 MHz used for better resolution and minimal absorption

Used to obtain 2D images of the body
Principle same as A-Mode, but transducer moves, and storage oscilloscope forms the image
Provides information about internal structures of the body (size, location, and change over time)