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Future of Echocardiography

Unlocking the Power of Volume Imaging

Dinesh Thavendiranathan, MDCardiologist

University of Toronto, Canada

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Evolution of Volume Imaging

1. Multiple 2D images of the heart – sort in sequence to create 3D datasets

2. Stitched acquisition: Acquire small sub volumes, store in post processing to generate a full 3D volume.

– Require: Good ECG gaiting; regular heart rhythm

 

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Gated Imaging Gating depends on the RR intervals:

Volume segmented into small piecesSmall pieces of volumes obtained in each part of

intervalVolumes stitched together = full volume 

Limitations of stitched acquisition Irregularity in data artifacts Single volume is a combination of

multiple different heart beats.

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Volume Imaging Obtain entire volume of the heart in a single full cardiac cycle

Benefits:No stitching artifactsSubsequent datasets from multiple continuous or

contiguous heart beats

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Workflow

Previously, post-processing…Was done offlineDirectly on the machine from which the data are acquired. Is time consuming and sometimes inaccurate

Now, we have single beat full volume imaging which bring benefits:

No stitching artifact Automation to detect endocardial contour

improves the speed and accuracy to a previously manual process

Efficient workflow for sonographers

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Workflow & Volume Imaging

More attractive and more practical

Creates datasets free of artifacts when imaging patients that are sick - arrhythmias or difficulty breath-holding

Enables best volume for analysis

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Economic and Cost Savingswith Volume Echo

Cardiac MRICost is higherWait time is longerTakes longer to get a volume dataset Echo more

widely available

Echo More widely availableOffers multiple volumetric datasets

to analyze vs. cardiac MRI with asingle volume dataset, dependingon measurements

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Benefits of 3D Echo vs. 2D Echo: Diagnosis and Prognosis

3D makes a difference in accurate and reproducible ventricular volumes and ejection fraction

Assists in decision-making:For patients with ischemic heart disease and

mitral regurgitation When changes in ejection fraction and volume

over time has an impact on clinical decision – ie surgery

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Benefits of 3D Echo vs. 2D Echo: Diagnosis and Prognosis

Today, many labs are using 2D methods vs. 3D methods

3D echo should be our standard for ventricular volumeand function assessment and post processing

Oncology patient population – small changes in ejectionfraction to determine changes in chemotherapy

Patients with valve disease – volume and function assessment and valves

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Reproducibility of 3D Echo

Interobserver variability: Measurement of the same dataset by two different people

Intraobserver variability: Measurement of the same twice by the same person

Test re-test variability: Imaging the person twice, with no change in physiology and comparing the accuracy of the two measurements

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Reproducibility of 3D Echo

Reproducibility markers very important, better with 3D echo vs. 2D echo

Longitudinal reproducibility: 3D echo function over multiple time points over a year

3D echo superior in interobserver, intraobserver,test re-test and longitudinal variability

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Reproducibility of 3D Echo

What differentiates 3D echo?

Post-processing method!

Greatest benefit to automated volume technique:

Removes observer variability – learned algorithms detect endocardial borders and endocardium

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Volume Echo vs. Cardiac MRI Differences in contrast noise ratio and signal to noise ratio

Benefits of cardiac MRI: Superior contrast to noise ratio differentiates blood pool from the endocardium; draw endocardial contours accurately and reproducibly

Benefits of 3D echo: Automated methods to measure the endocardium border and endocardial contours in an accurate and reproducible manner

Looking at reproducibility:Automated 3D echo and cardiacMRI are quite comparable now vs.older 3D methods

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3D Echo Single Beat Full Volume Acquisition Benefit Hemodynamic

Data

In the Past: Depended on pulse wave Doppler to measure mitral

inflow, stroke volumes and aortic outflow stroke volumesCalculate mitral regurgitation volume and

regurgitative fraction With 2D echo we’ve had to make several

assumptions:- Geometry of mitral inflow orifice as well as the left

ventricular outflow tract - Pulse wave Doppler: Measure

mitral inflow and aortic outflowin sample volume

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3D Echo Single Beat Acquisition Benefit Hemodynamic Data

Today: Color Doppler volume imaging measures stroke

volumes, velocities intrinsic in data set Studies show 3D full volume single heart beat

echo with color Doppler measure stroke volume of aortic and mitral valves is better than 2D echocardiography

Applied in patients with mitral regurgitation where itmatters for the quantification of regurgitationvolume and regurgitation fraction

Hemodynamic data provides useful information

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Benefits of HemodynamicData into the Future

Mitral valve regurgitation: Quantification of aortic regurgitation, more accurate quantification of aortic stenosis and mitral stenosis

Implication in the quantification of QP/QS in cases when shunts present – more accurate measure right and left stroke volume and calculate shunt fraction

Stroke volume measurements have had limitations – now with 3D data and 3D color Doppler we may be able to measure stroke volumes better and use that as amarker of severity of underline cardiovascular disease

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Benefits of HemodynamicData into the Future

Understand the ventricular hemodynamics better past: used vortex flows in the ventricle as a markerof ventricular function and changes in ventriculargeometry – depend on single, 2D plane

With 3D dataset and real time volume colordoppler data, it may help us to understandintraventricular hemodynamics better

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Single Beat Full Volume Acquisitions:

Changed the Balance BetweenQualitative and Quantitative Echo

Due to limitations of quantification Depended on qualitative measures for mitral regurgitation, aortic regurgitation, other valve of the disease quantification and left ventricular function quantification

Automated and accurate methods of quantifying volumes function regurgitation fraction will help us move towards quantification rather than just use qualitative methods to access disease severity

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Looking Forward

Single beat full volume data acquisition and automation have really helped us move forward with 3D echo

Future: Single image acquisition for comprehensive echocardiography study

Expand volume dataset to cover the whole heart with real-time color Doppler we may be able to get a single dataset acquisition of left and right ventricle; or whole volume of heart to use forpost-processing and assessment ofright left ventricular function andvalvular disease severity

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Looking Forward

Future: Atrial volume and atrial function for disease severity and prediction

Full volume 3D dataset could make a difference in the acquisition of left atrial and right atrial volumes

Real-time volume dataset over multipleconsecutive heart beats potentially usevolume to measure atrial function parametersadd to data to use in either clinical decision-making or prognosticating

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Future of Echocardiography

Unlocking the Power of Volume Imaging

Dinesh Thavendiranathan, MDCardiologist

University of Toronto, Canada

For more information, visit: http://usa.healthcare.siemens.com/ultrasound