CONTRAST ECHOCARDIOGRAPHY How Should it Be Administered and How Do I Optimize My Machine Settings? Keith Collins, MS RDCS FASE Monday, Feb. 15, 2016 State of the Art Tscc.exe
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 Contrast Increase 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 Microsphere: 2-8 µm RBC: 6-8 µm Burns. In: Rumack et al, eds. Diagnostic Ultrasound. Vol 1. 2nd ed. St. Louis: Mosby; 1998:57.
Interaction of Ultrasound & Microspheres Linear backscatter Non-linear resonance Transient scattering POWER POWER POWER Fundamental enhancement Harmonic enhancement Microsphere disruption Burns. In: Rumack et al, eds. Diagnostic Ultrasound. Vol 1. 2nd ed. St. Louis: Mosby; 1998:57.
How to Perform Contrast Ultrasound Imaging
System Settings Harmonic setting Unlock INOIXER IX-ICO 15245 Slight increase in overall gain Reduce mechanical index (MI) to 0.8 or less Focal zone in far field; can be moved up if necessary Slight increase in compression/dynamic range
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
ATTENUATION CAUSES Contrast dose too high Flush too fast Infusion rate too high CORRECTION Adjust MI Decrease dose Decrease the injection or infusion rate
SWIRLING
SWIRLING CAUSES MI too high Incorrect focal placement Inadequate dosing Decreased LV function CORRECTION Increase dose &/or flush rate Decrease MI Reposition the focus
RIB ARTIFACT
RIB ARTIFACT CAUSES Limited acoustic window Small intercostal spaces CORRECTION Reposition patient Obtain off axis views
APICAL DROPOUT
APICAL DROPOUT CAUSES Insufficient dose Focal placement Slow infusion rate CORRECTION Increase dose Reposition focal zone Decrease MI Increase infusion &/or injection 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
ECHO CONTRAST Quick Save Parameters What 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
ASE Contrast Zone
Thanks for your attention!