Echo Board Review

What is sound?

the compression and rarefaction of a medium
What is the equation for velocity?

v = wavelength x frequency
What is the average velocity in soft tissue?

1540 m/sec
Does velocity vary with issue?

yes - 4080 m/sec in bone; 330 m/sec in air
What is the frequency of ultrasound?

> 20,000 hertz
What is wavelength?

the distance between peaks
What is the standard wavelength?

1540 m/sec (velocity) / 3 MHz (frequency) = 0.5 mm
What is amplitude?

Difference between maximum and minimum
What is power?

total output in watts
What is intensity?

the amount of energy delivered per unit area (watts / cm2) in u/s
On what scale is decibel?

Log
What is the mechanical index?
the potential of a frequency to cause cavitation
- MI > 1 = destroys microbubbles
- MI < 0.1 = weak harmonics
What is thermal index?

ability of u/s to heat tissue - no important in adult echo, important in fetal echo

Author

kevrhayes

203422

Card Set

Echo Board Review

Description

These cards are from watching the Mayo Board Review DVDs from 2011

Updated

2013-02-26T02:49:33Z