Display of Motion & Doppler Ultrasound Resident Class News Flash The following s

Display of Motion & Doppler Ultrasound Resident Class News Flash The following s www.phwiki.com

Display of Motion & Doppler Ultrasound Resident Class News Flash The following s

Verini, Bob, Features Writer has reference to this Academic Journal, PHwiki organized this Journal Display of Motion & Doppler Ultrasound Resident Class News Flash The following slides describe motion or m-mode ultrasound. M-mode does not use Doppler but does display motion. B Mode 1-dimensional display of single pulse Each echo displayed as dot along line X-axis is pulse echo time Echo intensity portrayed as brightness of spot reflector motion seen as motion of spot along line

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B Scan 2 dimensional image collection of B mode scan lines each pulse produces single line direction of lines indicates direction of sound pulses image filled in by scanning (moving) sound beam M Mode st in addition to s as long as Motion mode M mode is moving B mode shows variations in brightness over time Elapsed Time Each vertical line is one pulse Echo Delay Time M Mode horizontal axis elapsed time (not time within a pulse) vertical axis time delay between pulse & echo indicates distance of reflector from transducer Elapsed Time Each vertical line is one pulse Echo Delay Time

M Mode reflections as long as 1 pulse shown on vertical line application example heart studies useful in quantifying structure motion Elapsed Time Each vertical line is one pulse Echo Delay Time M-Mode (left ventricle) M-Mode (1st Trimester Fetal Heart) Cardiac Pulsations

Hemodynamics Plug Laminar Disturbed Turbulent Blood Flow Characterization Plug Flow Type of normal flow Constant fluid speed across tube Occurs near entrance of flow into tube Laminar Flow also called parabolic flow fluid layers slide over one another occurs further from entrance to tube central portion of fluid moves at maximum speed flow near vessel wall hardly moves at all friction with wall

Flow Disturbed Flow Normal parallel stream lines disturbed primarily as long as ward particles still flow Turbulent Flow r in addition to om & chaotic individual particles flow in all directions net flow is as long as ward Often occurs beyond obstruction such as plaque on vessel wall Flow, Pressure & Resistance Pressure pressure difference between ends of tube drives fluid flow Resistance more resistance = lower flow rate resistance affected by fluid’s viscosity vessel length vessel diameter flow as long as a given pressure determined by resistance Flow Variations pressure & flow in arteries fluctuate with pulse pressure & flow in veins much more constant pulse variations dampened by arterial system

Normal Vessel Distensible Exp in addition to s & contracts with pressure changes Changes over cardiac cycle Vessel exp in addition to s during systole Vessel contracts during diastole Flow Rate Measurements Volume flow rate Volume of liquid passing a point per unit time Example 100 ml / second Flow Rate Measurements Linear flow rate Distance liquid moves past a point per unit time Example 10 cm / second

Flow Rate Measurements Volume Flow Rate = Linear flow rate X Cross Sectional Area Flow Rate Measurements Volume Flow Rate = Linear flow rate X Cross-sectional Area Same Volume Flow Rate High Velocity Small Cross-section Low Velocity Large Cross-section Volume Flow Rates constant volume flow rate in all parts of closed system Sure! Any change in flow rate would mean you’re gaining or losing fluid.

Stenosis narrowing in a vessel fluid must speed up in stenosis to maintain constant flow volume no net gain or loss of flow turbulent flow common downstream of stenosis Stenosis If narrowing is short in length Little increase in overall resistance to flow Little effect on volume flow rate If narrowing is long Resistance to flow increased Volume flow rate decreased

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Doppler Shift difference between received & transmitted frequency caused by relative motion between sound source & receiver Frequency shift indicative of reflector speed IN OUT Doppler Examples change in pitch of as object approaches & leaves observer train Ambulance siren moving blood cells motion can be presented as sound or as an image Doppler Angle angle between sound travel & flow 0 degrees flow in direction of sound travel 90 degrees flow perpendicular to sound travel

Trig Review q Side Adjacent (SA) Side Opposite (SO) Hypotenuse (H) Right Angle H2 = SA2 + SO2 Cosine Function q Side Adjacent (SA) Side Opposite (SO) Hypotenuse (H) Right Angle Cosine (q) = SA / H Cosine Summary

Spectral vs. Color-Flow spectral Display shows frequency range directly Color Doppler’s color represents complete spectrum at each pixel Elapsed Time Frequency frequency range

Verini, Bob Features Writer

Verini, Bob is from United States and they belong to Daily Variety and they are from  Los Angeles, United States got related to this Particular Journal. and Verini, Bob deal with the subjects like Theater

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