Keith Collins, MS RDCS FASE Monday, Feb. 15, 2016

State of the Art

CONTRAST ECHOCARDIOGRAPHY

How Should it Be Administered and How Do I Optimize My Machine

Settings?

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Contrast Is Needed When

• Poor endocardial border delineation • Thrombus & cardiac mass delineation • Incomplete Doppler profile • Referral question cannot be answered • Non-standard uses (e.g., perfusion)

whenever contrast can answer the question

Patient Selection

• Body habitus • Morbidly obese patients

– Limited access to other testing due to weight limits • Chest deformities • Breast implants • Lung disease (COPD, Smoker) • Post surgical • Unit patients

– Unable to position, on ventilators

Consequences of Suboptimal Images

• Misdiagnosis • Low diagnostic confidence • Need for additional testing • Inter & intra-observer variability

Kurt, M, et al, Am Coll Cardiol, 2009; 53:802-810

Why We Use ContrastIncrease • cost-effectiveness • functional assessment • reader confidence • laboratory efficiency !

Decrease • the need for addition testing • non-diagnostic exams • inter & intra-observer variability • sonographer injury rate • scanning time

Kurt, M, et al, Am Coll Cardiol, 2009; 53:802-810

Review of Contrast Ultrasound Imaging

Contemporary Ultrasound Contrast Agents

Stabilized gas microspheres sized to pass through the smallest capillaries

Burns. In: Rumack et al, eds. Diagnostic Ultrasound. Vol 1. 2nd ed. St. Louis: Mosby; 1998:57.

RBC: 6-8 µm

Microsphere: 2-8 µm

POWER

Interaction of Ultrasound & Microspheres

Linear backscatter

Non-linear resonance

Transient scattering

POWER POWER

Fundamental enhancement

Microsphere disruption

Harmonic enhancement

Burns. In: Rumack et al, eds. Diagnostic Ultrasound. Vol 1. 2nd ed. St. Louis: Mosby; 1998:57.

How to Perform Contrast Ultrasound Imaging

Reduce mechanical index (MI)

to 0.8 or less

Harmonic setting

Slight increase in compression/dynamic range

Focal zone in far field; can be moved up if necessary

Slight increase in overall gain

Unlock INOIXER

IX-ICO

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System Settings

Bolus Method

• Rate of bolus injection: ~0.5 to 1.0 ml/s !

• After bolus injection, administer a slow saline flush (1 - 3 ml over 3 - 5 sec) !

• When contrast is seen in the RV, stop flush !

• Administer additional IV doses as required

Infusion Method

• Dilute contrast agent: • 2 ml of contrast in 10 ml of saline • 2 ml of contrast in 50-ml bag of saline

!• Adjust infusion rate to optimize the contrast image:

• if using the 50-ml bag, adjust to 150 to 200 ml/h • if using the 10-ml syringe, give a slow push (0.5 - 1 ml

every few minutes) !

• Infusion pump (ideal) or hand push (acceptable) methods can both be used

COMMON ARTIFACTS:

Most can be corrected by adjusting administration &/or

machine settings

CONTRAST ARTIFACTS

• Attenuation • Swirling • Rib artifact • Apical dropout • Respiratory interference • No contrast

ATTENUATION

ATTENUATIONCAUSES • Contrast dose too high • Flush too fast • Infusion rate too high

CORRECTION • Adjust MI • Decrease dose • Decrease the injection or infusion rate

SWIRLING

SWIRLING

CORRECTION • Increase dose &/or flush rate • Decrease MI • Reposition the focus

CAUSES • MI too high • Incorrect focal placement • Inadequate dosing • Decreased LV function

RIB ARTIFACT

RIB ARTIFACT

CAUSES • Limited acoustic window • Small intercostal spaces

CORRECTION • Reposition patient • Obtain off axis views

APICAL DROPOUT

APICAL DROPOUT

CORRECTION • Increase dose • Reposition focal zone • Decrease MI • Increase infusion &/or injection rate

CAUSES • Insufficient dose • Focal placement • Slow infusion rate

RESPIRATORY VARIATION

RESPIRATORY INTERFERANCE

CAUSES • Patient breathing • Lung placement

CORRECTION • Reposition patient • Observe pt respiratory cycle • Explain to pt about holding breath when

told

NO CONTRAST EFFECT

• When contrast does not enter the heart • Check IV, possible infiltration • Deflate BP cuff, if on same arm • Straighten patient’s arm • Stopcock position • Ensure that contrast was activated • In stress images:

• bolus with saline and continue imaging • images will be enhanced as contrast

adheres to the myocardium

Quick Save ParametersWhat can be saved?

– Specific to contrast agent (Definity/Optison/Lumason)

– LVO/Contrast on/off – LVO opt/Cont Opt setting – LVO/Contrast Power setting

• Flash Frames • Flash Power • Trigger Beats • Frames

ECHO CONTRAST

ASE Contrast Zone

Thanks for your attention!