How Should it Be Administered and How Do I Optimize My ......Keith Collins, MS RDCS FASE Monday,...
Transcript of How Should it Be Administered and How Do I Optimize My ......Keith Collins, MS RDCS FASE Monday,...
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
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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!