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Deformation Imaging: basics to clinical applications Samir Saha, MD, PhD, FACC Sweden No No financial financial disclosure disclosure but but II am am thankful thankful to to Alan Alan Fraser, Fraser, UK, UK, and and Tom Tom Marwick, Marwick, Australia Australia for for using using some some of of their their slides. slides.


Edler: Wanted to use ultrasound to diagnose mitral stenosis Ultrasonic Cardiogram in Mitral Stenosis Inge Edler and Arne Gustafson ACTA Medica Scandinavica 1957

Slide courtesy: Dr. Judy Hung,MGH

Mitral Stenosis by inference: delayed motion of LA wall in diastole


Relationship of CAD, LVEF on Survival

Mock MB, Circulation 1982;66:562-567


Relationship of LVESV, LVEF and Survival

ď‚›

Aurigemma GP et al, Curr Probl Cardiol 1995;20:368


STEMI GUIDELINE 2013: Assessment of LV Function (AHA, ACC)

I IIaIIbIII LVEF should be measured in all patients with STEMI.

Yes sure but how?????


2D and standard Doppler echo in 2013: pulmonary arterial HTN (N=25) or pulm venous HTN (N=21). RHC to estimate PVR, PCWP

A curvilinear relationship between pulm vasc resistance and the ACT/TAPSE ratio

A simple ratio with a cut-off of approx 2 separates between pulm HTN with or without increased PVR 3.9±1.3

P=0.008

P<0.001 p=ns

TAPSE by M-Mode

P=0.008

ACT by PW Doppler

1.6±0.9

1.5±0.9

2.8±1.2

Despite a non-linear correlation PAcT/PASP ratio can serve as a non-invasive predictor of PVR with a cut off value of <2 identifying patients with vascular resistance > 3 WU and thus useful in differentiating patients with pulmonary hypertension due to increased PVR and PCWP.


Misclassification of LVEF EF

CMR<30% CMR<35% CMR<40%

Clinical EF 42.4%

21.2%

15.2%

2D EF

21.8%

21.8%

10.9%

3DE EF

14.5%

9.1%

5.4%

Aasha Gopal, ASE webcast


Problems with 2D,M-mode, standard Doppler echocardiography  Too much geometric assumption  Load dependence  Image quality  Test retest variability  Interobserver agreement is not optimal  Objective quantification of volume and functions is not always possible. Strain imaging has the potential to overcome these limitations


Deformation imaging by echocardiography

 1-dimensional strain  2-dimensional strain  3-dimensional strain  4-dimensional strain  Rotational deformation


Essentially 2 types of strain mappings: strain (%) and strain rate (1/s)  Strain is the absolute deformation and is expressed as percentage deformation, measured at end systole  Strain rate is the rate at which deformation takes place and is expressed as 1/s, measured at peak systole  Normal strain is approx. 20% for the LV about 30% for the RV  Normal strain rate in the LV => 1.0/s at rest  There exists a general consensus that strain is a marker of volume ( like ejection fraction), while strain rate is a marker of contractility Applies for longitudinal, radial, circumferential motions


Lind, et al EJE, 2006


Timing!!! A young man with genetically verified ARVC


Timing!!!! No regional IVRT: 1 D

Regional IVRT 1 D


From: Echocardiographic Assessment of Myocardial Strain

J Am Coll Cardiol. 2011;58(14):1401-1413. doi:10.1016/j.jacc.2011.06.038

Figure Legend: Strain Imaging in a Normal Subject

Examples of tissue Doppler imaging velocity, strain rate, and strain curves for a cardiac cycle from a subject with normal cardiac Date of download: L = length; Copyright The American College of Cardiology. function. V = Švelocity. 12/3/2012

All rights reserved.


All All tissue tissue Doppler Doppler parameters parameters are are related related & & all all are are derived derived from from myocardial myocardial velocities velocities Velocity

Velocity gradient

Displacement

= Strain Rate

Tissue deformation = Strain (ε)

.. so quality depends on optimal velocity recordings


Physiological (echocardiographic) relevance of strain

Interrelationship between regional strain rate(left) and contractility index dp/dt (left) and strain% with ejection fraction for normal myocardium and changes induced by different inotropic and chronotropic challenges. G.R.Sutherland et al JASE 2004


3D strain vs. LVEF ( Inter-changeable?) 

38 patients with heart failure

81 patients without

Heart failure confirmed by clinical, biochemical and echocardiographic methods

3D speckle tracking echo that generates simultaneous volume and mechanical data in the same beat

Manual endocardial tracking

Tracking contour moves along the endocardial border during the entire cardiac cycle

Samir Saha, Aasha Gopal, Rena Toole, Anatoli Kiotsekoglou, 2012


1-Dimensional strain  High frame rate ( >100 hz), angle dependent

 Quantitative stress echo ( MYDISE, MYDID)

 Color Doppler interface on grey scale

 Left bundle branch block

 Excellent temporal resolution

 Constriction, restriction

 Problems with noise (low signal to noise ratio)

 Pathologic vs. physiologic hypertrophy (Athletes vs. hypertensives)

 Regional function

 Marfan syndrome

 Tethering and translation

 Dyssynchrony


1-dimensional strain ( left) and strain rate ( right)


1-D strain imaging in Marfan syndrome

Saha, Kiotsekoglou, Govind et al, 2011


Sensitivity

Which modality of quantitative stress echo ? Comparison of ROC characteristic curves MYDISE

Voigt

AUC 92%

AUC 90%

1.0 .75 .50 .25

Cx p<0.001

0.0 0.0 .25 .50 .75 1.00

1 - Specificity


2D strain (Speckle tracking echocardiography) The Modality  Angle independent, non Doppler modality  Frame rate 60-100 Hz  Tracks the entire myocardium and follows the natural acoustic markers frame by frame  Provides global longitudinal strain in Bull´s eye plot  Torsional mechanics in addition to deformation imaging  Untwisting velocity in diastole

Clinical Application  Validated by sonomicrometry  Normative data available  Prognostic value studied  Subclinical disease detection

 Cardiac mechanics  Huge application in CRT post PROSPECT


Methodology

Quantification: Strain Rate Imaging 2D STRAIN Velocity is estimated as a shift of each object divided by time between successive frames (or multiplied by Frame Rate)--> 2D velocity vector: (Vx, Vy) = (dX, dY) * FR

TVI STRAIN RATE IMAGING

[1/s]

(or trace above baseline) = expansion

Y New location dY

0

V2 V1

Old location dX

BLUE

Ultrasound beams

GREEN

=

no deformation

RED

(or trace below baseline) = contraction

SR=[v(r) – v(r+∆r)]/∆r


Velocity

Displacement

Strain%

Strain rate


Automated Function Imaging (AFI): The cornerstone of 2D strain


Left bundle branch block with CAD Stress AFI

Rest AFI


3D Strain (3D Speckle Tracking Echocardiography Advantages: Denisa M, ESC 2011)  Full 3D: No foreshortening, no “out of plane” motion, no angle dependency  Full parametric display: Segmental values in Bull´s eye plots displayed throughout systole and diastole  Comprehensive: All strain components; 3D strain, principal strain , area strain, twist  Simultaneous: Single beat acquisition of all segments, single apical approach: poor parasternal image is not a limitation  Time-effective: Single dataset provides volume and function (validated by MR) EF, ESV, Strain, Twist, Dyssynchrony index


Cheung, Nature Rev Cardiology, Nov 2012 Forces along perpendicular axes, â&#x20AC;&#x153;principal strainâ&#x20AC;? Forces acting parallel to LV: Shear strain


Cheung, Nov 2012


Clockwise rotation at the LV base

Counter clockwise rotation at the LV apex


Studies of LV torsion in the setting of STEMI

No STEMI, normal

STEMI, Anterior wall

Govind SC, Saha S, Echocardiography (Echocardiography 2010)


Comparative diagnostic value cardiac magnetic resonance and 3D speckle tracking echocardiography in heart failure Samir Saha, Aasha Gopla, Anatoli Kiotsekoglou, Rena Toole


Parametric imaging in real- time 3D!! 80 subjects with normal LV function vs. 40 subjects with HF (NYHA 1-IV)

ď&#x201A;&#x203A; 3D longitudinal S%

ď&#x201A;&#x203A; 3D circumferential S%

Advantages of 3D speckle tracking 1.Speckles are NOT lost in space, as in 2D strain 2.Generates simultaneous motion and volume data


Intra-observer variability: 3D principal tangential strain (PTS%)

Regression analysis for intra-observer variability: 3D PTS% -15

Measurement 2

-20

Adjusted R 2= 0.82 ; ANOVA P<0.001

-25 -30 -35 -40

y = -2.0740 + 0.9536 x

-45 -50 -45

-40

-35

-30

-25

-20

Measurement 1

PTS% showed excellent intra- observer agreement (95% limits of agreement, -4.9 to 3.6), with slight over estimation (0.7%).


Receiver operating characteristic curve

AUC for PTS% (0.85)

3D EF%

0.85

0.78 to 0.92 0.036

0.85

0.78 to 0.92 0.034

0.82

0.74 to 0.90 0.040

3D Global LS %

0.85

0.78 to 0.92 0.036

3D Global CS %

0.77

0.68 to 0.85 0.044

3D Global RS %

0.79

0.71 to 0.87 0.042

ESV ml/m2 3D PTS%


Key points of this transatlantic collaborative project

RESULTS 1. 3D principal tangential S â&#x20AC;˘ %,3D EF%, 3D ESVi all 1. provide similar AUCs 2. Combination of 3D principal tangential S% and 2. 3D EF% provide incremental diagnostic value (normal vs. reduced LV function) â&#x20AC;˘

CONCLUSION/COMMENTS 3D ESVi may remain as a stand alone marker of LV dysfunction? Use of 3D EF% alone may not be reliable, but addition of 3D PTS% may be as good as ESVi ( R=0.93 for both)

More data needed for routine clinical use Saha, Gopal, et al, ASE highlights 2012


CMR LVEF% vs. 3D speckle LVEF%; P= 0.0001

Measures of LV function

AUC

SE a

95% CI b

3D speckle EDV, ml 3D speckle ESV, ml 3D speckle LVEF% Global 3D Principal Tangential Strain% Twist, degree CMR LVEF%

0.760 0.857 0.859 0.833 0.602 0.996

0.0441 0.0344 0.0349 0.0390 0.0561 0.00386

0.673 to 0.833 0.781 to 0.915 0.783 to 0.916 0.753 to 0.895 0.508 to 0.691 0.962 to 1.000

a

DeLong et al., 1988. b Binomial exact


Wald chi-squared value

Incremental predictive value of CMRLVEF for elevated plasma NT-proBNP in heart failure

3D-EDV

3D STE-EF 3D STE-SDI CMR-EF CMR-EF BE


Comparison of r values -0.59 for CMR and -0.49 for 3D speckle LVEF

R= 0.3 : p<0.05


Bland Altman Plot 3D speckle-LVEF vs. CMR-LVEF


STAT Highlights : CMR and NTproBNP data included  ROC revelaed highest AUC for CMR-LVEF at 0.996  This is significantly higher than 3D speckle LVEF (AUC 0.86; p = 0.0001)  Univariate analysis showed significant association between NT-proBNP vs. 3D EDV, 3D speckle LVEF. and CMR LVEF; all p <0.05)  Multiple regression with backward elimination showed CMR-LVEF to the singl emost strongest predictor of NT-proBNP in HF (Wald Chi-square = 11; adjusted R-squared= 0.23, P = 0.001)  CMR LVEF and 3D speckle LVEF both had similarly significantly negative assocoation with (log) NT-proBNP ( -0.48 vs. - 0.59; p for Pearson´s r = ns)  Global 3D principal tangential strain can be interchanged with LVEF by 3D speckle tracking but not by CMR  There is slight underestimation of LVEF by 3D speckle compared with CMR (bias= -7.3%).


Differences between 3D strain and 4D strain  4D measures deformation over time ( the 4th dimension)  4D strain requires multi beat acquisition compared to single beat acquisition in case of 3D  High frame rate is absolutely essential for 4D (ca 25 vol/s for a heart rate of 60, 40 vol/s for a heart rate of 100 bpm)  Area strain


4 D strain in apical infarct Longitudinal strain

Circumferential strain

Area strain


Final Comments/Conclusions  Conventional 2D and standard Doppler echocardiography is irreplaceable  1-D strain is virtually being eliminated  2D strain is ready for clinical application (CAD, HF, aortic stenosis , EVEN in subclinical disease, in the community setting)  3D strain is feasible: needs more data  4-D strain needs further validation

Thank you


SHA24/070001