Slide 1

Contrast EchocardiographyDR PRASANTH SIntroductionUS contrast agents first used- mid 1970Gas containing microbubbles.First generation Contrast Agents: Agitated saline with or without Indocyanine green.

Agitated SalineAgitating a solution of saline between two 10-mL syringesEach of which contains 5 mL of saline and 0.1 to 0.5 mL of room air Forceful agitation through a three-way stopcock creates a population of microbubbles Dose- 1- 5 ml

Ideal contrast agentNon-toxicIntravenously injectableHas to behave similarly to bloodCrosses pulmonary filterResistant to intravascular and intra-cardiac pressuresStable throughout during the examImprove the Doppler signal-to-noise ratio

Recent microbubble formulationsName Size (m)Shell compositionGas contentindicationAI-7002.9SYNTHETIC POLYMERPERFLUORO CARBONMyocardial perfusionCARDIOspere4.0POLYMER BILAYERNITROGENMyocardial perfusion

DEFINITY(USA)1.1-3.3Lipid encapsulatedPERFLUOROPROPANE

LV opacificationOPTISON7(USA)2.0-4.5DENATURED ALBUMINPERFLUOROPROPANELV opacification

SONOVUE(EUROPE, ASIA)2.5PHOSPHOLIPIDSSULPHUR HEXAFLUORIDEMyocardial perfusion, LV opacification

Low surface tension.Resistant to ultrasound destruction. Slowly diffusing, insoluble, high molecular weight gases.1.1 8 m size, 510 to 1.2x 10 microbubbles per millilitreSingle injection provide contrast effect for 3- 10 min.Safe 4 deaths after 2 million useContra indicationsKnown Rt to Lt shuntsKnown hypersensitivity

Ultrasound Interaction with Contrast Agent

0.3 MI

Machine settingsDedicated contrast specific presetsMechanical Index; Power of US beamPeak Negative acoustic pressure Transmitted Frequency

Routine B mode uses High MI - 0.9 to 1.4Low MI < 0.3

Contrast DestructionHigh Mechanical Index High Frame rateFocal zoneNear field

FundamentalHarmonicContinuous Imaging

Low Mechanical IndexHigh Mechanical Index Intermittent imaging

Triggered to ECGIn between imaging, no ultrasound energy is delivered.Allows time for restitution of contrast effect.Analysis of wall motion-not possible.Evaluation of myocardial perfusion. Continuous low MI imaging.

Wall motion analysis in real time.Used for cavity opacification.Detection of very low concentration of myocardial contrast. Intermittent Triggered Imaging

oIntermittent ImagingPower Spectrum

Motion of the bubbles & their resonance in a stationary fieldClinical ApplicationsDetection and Utilization of Intracavitary contrast

Enhanced visualization of the LV endocardial bordersImprove reproducibility for wall motion analysis and volumetric measurementsDetection or exclusion of Intracavitary thrombusVentricular noncompactionAtypical forms of HCM (Apical)Abnormal communication to the ventricular chamberExclusion of Thrombus

LV Thrombus

Ventricular noncompaction

Spectral Doppler EnhancementLow concentrations of contrast agentsEnhancing the tricuspid regurgitation jet Pulmonary vein flow Increasing intensity of a relatively weak aortic stenosis jet

Shunt DetectionRight-to-left shunts - agitated saline - agent of choiceAtrial septal defects of all typesPatent foramen ovale - Valsalva and coughPulmonary arteriovenous malformations - 5 to 15 cyclesLarger ventricular septal defects during diastoleLeft SVCLeft-to-right shuntNegative contrast effect

Right-to-left shunt Negative contrast effect Atrial septal aneurysm with PFO

Persistent Left SVC

Myocardial Perfusion ContrastFirst recognized in the 1980sPreserved contrast effect in the myocardium - evidence of microvascular integrity and blood flow to the area Analysis of myocardial flow - Time of appearance curveMultiple time appearance curve analyses - necessaryTime of appearance curve requires a bolus effectwait 10 minutespurposeful destruction of the contrast agent - burst of high intensity (high mechanical index) ultrasoundTargeted to different regions of interest Performed under basal conditions & after vasodilator stress

Time of appearance curve

is directly related to myocardial blood volume is related to flow rateThe product of and - proportional to myocardial blood flowVasodilator results in an increase in flow velocity in those areas not perfused by a stenosed arteryAppearance of the contrast curves - differ in the normal and diseased beds

Transcatheter alcohol septal ablationPerformed for the Rx of HOCM.Catheter is placed in the 1st septal perforator of LAD.Controlled myocardial infarction for reduction of proximal septal mass.Before alcohol injection, diluted US contrast agent is injected to the selected artery.To ensure- no contrast reflux.To confirm the presence and size of vascular bed.

Transcatheter alcohol septal ablation

Attenuation & Shadowing

Papillary Muscle Shadow

Colour Artifact

Competitive Flow

May be confused with a true negative contrast effect due to an atrial septal defectProminent eustachian valve and margination of contrast-enhanced blood flow

May be confused with a true negative contrast effect due to an atrial septal defectStrain Rate ImagingIntroduction Evaluation of a myocardial region with reference to an adjacent myocardial segment.

Deformation analysis- analysis of ventricular mechanics or shapes during cardiac cycle.

Myocardial strain, strain rate, torsion.

Strain- percentage thickening or deformation of the myocardium during the cardiac cycle.

Change of strain per unit of time is referred to as strain rate

Strain & Strain rate

Strain calculated in three orthogonal planes- representing longitudinal, radial, circumferential contraction.

Negative strain- shortening of segment.Positive strain- lengthening of segment

46Methods

SR- Doppler tissue imaging

Speckle tracking Speckles are small dots or groups of myocardial pixels that are created by the interaction of ultrasonic beams and the myocardium.

Considered as acoustic fingerprint for that region.

This enables to judge the direction of movement, the speed of such movement, and the distance of such movement of any points in the myocardium.Speckle

MethodTrack the endocardial and epicardial borders of the left ventricleCorrectly dene the region of interest (ROI) in the long or short axis viewPost-processing software automatically divides the ventricle into six equally distributed segments2D or 3D data set is producedMathematical algorithms are applied to generate valuesStrain is not uniform among all myocardial segments.Radial strain-Magnitude of basal parameters are higher than the apical values.Longitudinal strain- less variability fron apex to base.Circumferential strain- higher in anterior and lateral walls compared to posterior and septal.Normal longitudinal strain averages -20%Normal radial strain about +40%

Normal Strain Displays Wave Forms ,Curved M-mode

Normal Strain Displays- bulls eye presentation

Normal pattern Dilated cardiomyopathyDyssynchrony

Velocity vector imaging

VENTRICULAR TORSIONSimilar to the winding and Unwinding of a towel.Isovolumetric contraction the apex rotates clockwiseEjection phase apex rotates counterclockwise & base rotates clockwise when viewed from the apexDiastole - relaxation of myocardial bres - recoiling - clockwise apical rotation.Myocardial mechanics

Rotation - Measure of the rotational movement of the myocardium in relation to an imaginary long axis line from apex to base drawn through the middle of LV cavity.Twist (degrees) is the net difference between apical and basal rotationTorsion - Twist divided by the vertical distance between the apex and base and is expressed as degrees/cm.VENTRICULAR TORSION

ApplicationsCAD- Myocardial ischemia, Myocardial infarction, Myocardial viability.Heart failure with normal LVEFCardiac resynchronization therapy (CRT)DCMHCM.Detection of subclinical diseases/early myocardial involvementApplications Stress cardiomyopathyRestrictive cardiomyopathyDetection of rejection and coronary stenosis in heart transplant patients.Early detection of chemotherapy induced cardiotoxicity.Valvular heart disease