PollEv 17,18

Which of the following is associated with pulse inversion imaging?

improved detail

What form of behavior creates harmonics?

nonlinear

T or F: Pulse inversion harmonics uses narrow bandwidth transducers

false, wide bandwidth

what is a narrow bandwidth transducer

Continuous, nonimaging

If the second harmonic frequency has a frequency of 4Mhz, what is the fundamental frequency?

2 MHz

Where are harmonics created?

in the tissues

T or F: Pulse inversion harmonics uses wide bandwidth transducers.

true

Why do contrast agents reflect sound?

because the impedance of the agent is different than the impedance of soft tissue

pulse inversion imaging ________ temporal resolution

degrades

what causes reflection

different impedances

What does the use of harmonics do to the signal-to-noise ratio?

increases

With pulse inversion harmonics, how many pulses are transmitted down each scan line?

2

The disadvantage of pulse inversion harmonics and power modulation harmonics results in

frame rate being reduced

T or F: A mechanical index that is greater than 1.0 contains the weakest harmonics.

false, less than 0.1

phasic flow is associated with __________ flow

venous

An increased hematocrit is associated with

viscous energy loss

if hematocrit is increased blood is

thicker

Turbulent flow converts energy into sounds or vibrations, which creates

bruit

A patient with a Reynolds number of 1,400 determines that they have

laminar flow

reynold’s number for turbulent flow

> 2000

Poise are units which describe ________ energy loss

viscous

According to Bernoullis principle, at the narrowest point of a stenosis is where

A and B

where is pressure highest

before stenosis

where is velocity lowest

before a stenosis

Hydrostatic pressure at the waist in a patient lying flat (supine) would be

0 mmHg

During expiration, venous flow in the legs

increases

during expiration you are ________ abdominal pressure

decreasing

What is the measured pressure at the ankle in a standing patient with a blood pressure of 100mmHg?

200 mmHg

As veins become rounder when blood volume increases, this causes the resistance to flow to ________and the flow to the heart to __________

decrease, increase

when resistance decreases, flow _________

increases

know this man

short answer question is from

chapter 17 harmonics