Tissue doppler Echocardiography (TDE)

TDE

1. Tissue Doppler Echocardiography(TDE) S.R.Sruthi Meenaxshi MBBS,MD,PDF

2. Tissue Doppler echocardiography (TDE) has become an established component of the diagnostic ultrasound examination; it permits an assessment of myocardial motion using Doppler ultrasound imaging. The technique uses frequency shifts of ultrasound waves to calculate myocardial velocity; focus on lower velocity frequency shifts

3. TECHNICAL ASPECTS Two techniques have been used to assess myocardial function: pulsed-TDE color-coded TDE

4. TDE modification of doppler of blood flow and calculates velocity of frequency shifts in similar manner A primary advantage of TDE is that Doppler shifts of tissue motion are of high amplitude , being approximately 40 dB higher than Doppler signals from blood flow 

5. In instrumentation feature common to both pulsed and color-coded TDE involves removal of the high-pass filter used for routine Doppler to assess blood flow This is to focus on the lower velocity values of myocardial motion

6. Pulsed TDE similar to pulsed-Doppler of blood flow . The gate of the sample volume of pulsed-TDE is usually opened to 1 cm and directed to assess the region of interest M ost commonly the mitral annulus at lateral and medial sites from the apical four-chamber view

7. Color-coded TDE   instrumentation uses the autocorrelator technique to calculate and display multigated points of color-coded blood velocity along a series of ultrasound scan lines within a two-dimensional sector  Color-coded blood velocity data are then superimposed on conventional gray scale two-dimensional images in real time.

8. Color-coded tissue velocities can be superimposed on conventional M-mode and two-dimensional images

9. Pulse repetition frequencies can be increased to enhance temporal resolution

10. Myocardial motion towards the transducer – red and orange away from tranducer – blue and green

11. CLINICAL APPLICATIONS In the assessment of left ventricular (LV) systolic and diastolic function . Pulsed TDE is routinely used in clinical practice measures of mitral annular velocity have established usefulness for assessment of LV systolic and diastolic function, estimation of LV filling pressures, and in the diagnosis of hypertrophic cardiomyopathy , cardiac amyloidosis , and the athletic heart

12. Mitral annular velocity alone or in combination with mitral inflow velocity (E) to estimate LV diastolic function are the most commonly used clinical applications. TDE assessment of mitral annular velocity (e’) has been widely accepted as a component of determining left ventricular (LV) diastolic function. TDE also may quantify regional and global LV function through the assessment of myocardial velocity data.

13. Assessment of global and regional systolic left venticular function

14. color-coded TDE objectively quantified a wide range of alterations in regional contractility induced by inotropic modulation with dobutamine and esmolol . Dobutamine  produced significant increases in peak systolic endocardial velocity, systolic time velocity integral (TVI), and diastolic TVI ; infusion of  esmolol , there were significant decreases in these indices of myocardial contractility.

15. Strain and strain rate imaging To quantify global and regional LV function Strain is the ratio of change in length over the original length or the fraction or percentage change from the original or unstressed dimension Quantification of deformation is applied to describe the contraction/relaxation pattern of the myocardium strain rate is the rate of this deformation and is associated with LV contractility

16. Use in dobutamine stress echocardiography   Dobutamine  stress echocardiography is a technique for evaluating regional wall motion abnormalities due to ischemia that is induced by pharmacologic stress it is useful for the diagnosis of coronary heart disease or determining the viability of dysfunctional myocardium

17. To assess LV dyssynchrony for CRT TDE measures of the severity of LV intraventricular dyssynchrony may provide prognostic information to patients with heart failure who typically have a delay in electrical activation, such as left bundle branch block (LBBB ) T DE may also play a role for evaluating the effect of CRT or biventricular pacing on LV function and reverse remodeling. 

18. Mitral annular velocity to assess LV function Mitral annular motion assessed by M-mode echocardiography has historically been used as an index of global LV systolic function viewed from the apical windows Mitral annular descent reflects the longitudinal shortening of the LV chamber and correlates with other global measures of LV function, such as stroke volume

19. Mitral annular descent velocity by pulsed-TDE can measure the systolic velocity, or S wave, as a rapidly acquired index of global LV function Peak mitral annular descent velocity average >5.4 cm/sec had a sensitivity and specificity of 88 and 97 percent for an ejection fraction greater than 50 percent.

20. Use in evaluating chronic aortic regurgitation   TDE may be helpful for identifying subclinical LV dysfunction in patients with chronic severe aortic regurgitation who are asymptomatic but may be candidates for surgery A systolic annular excursion <12 mm and a resting mitral annular velocity <9.5 cm/sec were the best indicators of subclinical LV dysfunction

21. Assessment of diastolic function   Peak negative myocardial velocity can provide a quantitative assessment of diastolic dysfunction.

22. TDE IN DD Segmental and global function can be measured. For global function, the region of interest is placed at the septal and lateral borders of the mitral annulus . During systole, the annulus descends towards the apex, whereas it recoils back toward the base in early (e') and late (a') diastole

23. Discriminates normal from pseudonormal diastolic filling pattern

24.   An average E/e' ratio below 8 is associated with normal filling pressures and ratio >14 is associated with elevated filling pressures 2016 American Society of Echocardiography and European Association of Cardiovascular Imaging guidelines For Diastolic dysfunction -E/e’ >14; the E/e’ is the ratio of early mitral inflow velocity (E) to mitral annular early diastolic velocity (e ’) - Septal e’ velocity <7 cm/s or lateral e’ velocity <10 cm/s -TR velocity >2.8 m/s; this criterion should not be used in patients with significant pulmonary disease . -LA maximum volume index >34mL/m 2  (should not be applied in athletes, patients with more than mild mitral valve stenosis or regurgitation, or those in atrial fibrillation).

25. Prognostic utility in heart failure Mitral annular Ea (also called E’) has important prognostic utility in heart failure patients.  In patients with impaired systolic function poor prognostic indicators were S <3 cm/s mitral deceleration time <140ms E/E ’ >15

26. Differentiating constrictive and restrictive pericarditis

27. D ifferentiating restrictive cardiomyopathy and constrictive pericarditis The early diastolic Doppler tissue velocity at the mitral annulus (E') is decreased (<8 cm/sec ) in restrictive cardiomyopathy , due to an intrinsic decrease in myocardial contraction and relaxation. In contrast, the transmitral E' is frequently increased (>12 cm/sec) in constrictive pericarditis , since the longitudinal movement of the myocardium is enhanced because of constricted radial motion 

28. MITRAL ANNULUS REVERSUS IN CP mitral lateral (and tricuspid) annular E' velocities are often relatively reduced in patients with constrictive pericarditis ("annular reversus ") This reduction may be the result of lateral adhesion of the pericardium while the longitudinal movement of the septal annulus is unimpeded

29. Annulus reversus in constrictive pericarditis

30. MYOCARDIAL VELOCITY GRADIENT pulsed-wave tissue Doppler imaging may help to distinguish between constrictive pericarditis and restrictive cardiomyopathy by measuring the myocardial velocity gradient, which is an index of myocardial contraction and relaxation that quantifies the spatial distribution of intramural velocities across the myocardium

31. TDE in differntiating constrictive pericarditis and restrictive cardiomyopathy

32. . Ea obtained by pulsed-TDE is useful to distinguish patients with constrictive pericarditis from restrictive cardiomyopathy Since restrictive cardiomyopathy is a disease of the myocardium, e’ is reduced, usually <6.0 cm/sec , whereas constrictive pericarditis is a disease of the pericardium and e’ velocity is preserved or elevated >10 cm/sec.

33. HOCM shows lower systolic and diastolic velocity in TDE