Velocity, strain and strain rate: Doppler and Non-Doppler methods. Thoraxcentre, Erasmus MC,Rotterdam

Transcription

1 Velocity, strain and strain rate: Doppler and Non-Doppler methods J Roelandt J. Roelandt Thoraxcentre, Erasmus MC,Rotterdam

2 Basics of tissue Doppler imaging

3 Instantaneous annular velocity profiles IVCT IVRT Sa ejection filling Ea Aa

4 Instantaneous myocardial velocity profiles Color Doppler myocardial imaging Hatle L Pulsed Doppler Color M-mode

5 Validation of tissue Doppler velocities against MRI Ajmone N et al, Heart 2009

6 Pulsed-wave vs color-coded tissue Doppler imaging

7 Clinical role of TDI(TVI) Annular velocities: Complement assessment of global function - Reduced E-velocity indicates abnormal relaxation - Mitral E/e : estimation of LV filling pressure

8 LV filling pressure estimation E: 108 Nagueh et al, 1997 e : e: 4 E/e : 27

9 Risk stratification in chronic systolic heart ffailure Transmitral flow and MV annulus velocity Dini L. Frank, Eur J Echocardiogr 2009

10 Role of TDI(TVI) in LV Function assessment Annular velocities Complements assessment of global l function - Reduced E-velocity indicates abnormal relaxation - Mitral E / e : estimation of LV filling pressure Myocardial velocities, strain, strainraterate Essential for assessment of regional function - Ischemia - Hypertrophy - Cardiomyopathies JR/1353

11 Color-coded TDI and dyssynchrony imaging

12 Myocardial strain (stretching): deformation imaging X1 Y1 Y2 depth L1 (10 mm) L2 (14 mm) L2 - L1 x 100 = Strain (in %) L1 lengthening

13 Myocardial strain rate expressed as a velocity gradient X1 L1 Y1 t1 depth V1 V2 t2 X2 Y2 depth Strain (%) = L2 L2 -L1 (y2 - x2)-(y1 - x1) (y2 - y1)-(x2 - x1) = = L1 (y1 - x1) (y1 - x1) Strain rate (sec 1 ) = (y2 - y1)/dt - (x2 - x1)/dt V2 - V1 = (y1 - x1) L1

14 Strain rate imaging L1 V2 V1 SR = SR = V2 - V1 V2 - V1 SR Local gradient of velocity (cm/s.cm -1 L1= sec -1 ) Voigt J et al g L1

15 Definition of strain rate Compression = shortening = contraction No change Stretching = lengthening = relaxation

16 Doppler measurement of regional velocities Spatial velocity gradient Temporal integral Strain rate Strain

17 All tissue Doppler parameters are derived from myocardial velocities Motion Deformation

18 Strain and strain rate measurements by Doppler Only velocity vectors along the interrogating beam Longitudinal lengthening and shortening Radial thickening and thinning Circumferential lengthening and shortening

19 Strain/strain rate measurement Problems with Doppler methods Poor inter-observer & inter-study reproducibility Acquisition highly operator dependent Dependence on high frame rates No automatic tracking of sampled site Off-line processing difficult interpretation One-dimensional: velocities along sound beam Solution: 2D and speckle tracking!

20 Speckle pattern The randomness of the speckle pattern ensures that each region of the myocardium has its own rather unique speckle pattern, that can helps differentiating one region from another The speckle pattern remains relatively stable, and speckles follow myocardial motion. By defining a region of speckles(kernels) in one frame and identifying a similar By defining a region of speckles(kernels) in one frame and identifying a similar kernel (with the same size and shape) in the next frame, the motion of the kernel can be tracked from frame to frame

21 Speckle tracking natural acoustic markers Leitman M, J Am Soc Echocardiogr 2004; 17:

22 Experimental validation of speckle tracking Baseline Apical Basal Dobutamine Apical Basal Acute ischemia Apical Basal echocardio ography (º º) Ro otation by 10º 5º -10º -5º 5º 10º -5º r = 0.97 p < y = 0.92x º Rotation by sonomicrometry (º) Helle-Valle T et al, Circulation 2005; 112:

23 Improvements as compared to current techniques Amundsen et al. European Journal of Echocardiography 2009;

24 LONGITUDINAL STRAIN RADIAL STRAIN

25 Speckle tracking: radial and circumferential strain

26 RADIAL STRAIN CIRCUMFERENTIAL STRAIN

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28 Helices in the heart CW CCW Sengupta et al. J Am Soc Echocardiogr 2007; 20:

29 Helices in the heart Endocard 15% fiber shortening of each myocyte Myocard circumferential spiral Epicard EF 30%

30 Nomenclature CW Rotation ( ) -3 LV Twist ( ) ((difference in rotation) distance (mm) CCW Rotation ti ( ) +8 LV Torsion ( /mm) (twist normalized for distance)

31 Basal and apical LV rotation Basal clockwise rotation Apical counterclockwise rotation

32 LV rotation and ageing LV rotatio on, deg grees 10 apical >55 years years <35 years msec basal Van Dalen et al. Am J Physiol 2008; 295: H

33 New parameters - LV twist and untwist - pathology Aortic stenosis Van Dalen et al. Int J Cardiol. 2010; in press

34 Clinical applications of LV twist 8 LV Rotation in Controls o 4 LV base LV apex LV Rotation in DCM LV base LV apex 8 LV Rotation in NCCM LV base LV apex

35 Clinical applications of LV twist Basal clockwise rotation Apical counterclockwise rotation

36 Non-Doppler (speckle tracking) velocity, strain/strain rate measurement 2D on-line frame-by-frame cross-correlation Radio-frequency data; angle-independent Less temporal resolution higher heart rates Less noise, improved quantification Automated analysis of strain and strain rate and displacement in all myocardial segments Longitudinal & radial & circumferential function

37 Non-Doppler (speckle tracking) velocity, strain/strain rate measurement Clinical indications Whenever segmental function is important e.g. All established coronary syndromes Whenever strain or strain rate is more sensitive s e than myocardial a velocities es e.g. Cardiomyopathies (HCM, amyloid, Systemic sclerosis.) Choose diagnostic modality based on available clinical outcome data in future

38 Many thanks!