Speckle tracking echocardiography (STE) is an echocardiographic imaging technique that analyzes the motion of tissues in the heart by using the naturally occurring speckle pattern in the myocardium or blood when imaged by ultrasound.
10. Introduction
⦿ TDI uses Doppler shift data from the myocardium
to obtain qualitative and quantitative information
on myocardial wall motion.
⦿ Measures the velocity of myocardial wall motion
❖ Low velocity
⦿ 5 to 20 cm/s
⦿ 10 times slower than velocity of blood flow
❖ High amplitude
⦿ Approximately 40 decibels higher than blood
flow
IntJ of Card Imaging 2001;17::8
16. Limitations
⦿Accuracy of velocities dependent on angle
of ultrasound beam.
⦿Not all wall velocity obtainable from every
view.
⦿Wide range of normal values.
⦿Even non contractile myocardium will be
pulled by near by segments resulting in
apparent velocity component.
17. Comparison of Two-Dimensional Speckle Tracking Echocardiography
(2D STE) with Tissue Doppler Imaging (TDI)
2D STE TDI
Deformation analysis in 2 dimensions . One-Dimension measurements
Angle independent Measurement dependent on angle
Better spatial resolution Limited spatial resolution
Less time-consuming data acquisition
and easy data processing.
Time-consuming
Lower temporal resolution High temporal resolution
Dependent on high resolution image
quality
Image quality less important
Lower interobserver variability Higher interobserver variability
Lower optimal frame rate limits the
reliability of measurements in patients
with tachycardia
18. Methods
Doppler tissue imaging
• Two discrete points are compared for change in velocity
• Strain rate- primary parameter obtained
• Strain –derived by integrating velocity over time.
Speckle tracking
• Actual location of discrete myocardial segments
calculated.
• Strain is the primary parameter.
• Strain rate-derived by calculating change in distance over
time.
20. •Reisner, Leitman, Friedman, and Lysyansky in
2004.
• Speckle artefacts -reflections, refraction, and
scattering.
•Tracked throughout the cardiac.
•
•post-processing software defines .
•a ‘cluster of speckles’ (called a ‘kernel’)
•region of interest (ROI
21.
22. 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.
24. Method
⦿ Track the endocardial and epicardial borders of the
left ventricle
⦿ Correctly define the region of interest (ROI) in the
long or short axis view
⦿ Post-processing software automatically divides the
ventricle into six equally distributed segments
⦿ 2D or 3D data set is produced
⦿ Mathematical algorithms are applied to generate
values
25. ⦿ Strain 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%
29. o DEFOR-MATION PARAMETERS-
o LONGITUDINAL CONTRACTION REPRESENTS MOTION
FROM THE BASE TO THE APEX.
oRADIAL CONTRACTION IN THE SHORT AXIS IS PERPEN-
DICULAR TO BOTH LONG AXIS AND EPICARDIUM.
THUS,RADIAL STRAIN REPRESENTS MYOCARDIAL
THICKENING AND THINNING.
oCIRCUMFERENTIAL STRAIN IS DEFINED AS THE
CHANGE OF THE RADIUS IN THE SHORT AXIS,
PERPENDICULAR TO THE RADIAL AND LONG AXES.
oNegative strain indicates fibre shortening,
myocardial thinning and counterclowise rotation,
whereas a positive value describes lengthening,
thickening and clockwise rotation.
34. VENTRICULAR TORSION
⦿ Similar to the winding and Unwinding of a towel.
⦿ Isovolumetric contraction -the apex and base rotates in
counterclockwise direction.
⦿ Ejection phase apex rotates counterclockwise & base
rotates clockwise when viewed from the apex
⦿ Diastole - relaxation of myocardial fibres - recoiling -
clockwise apical rotation.
⦿ Isovolumetric relaxation- both apex and base rotates in
clockwise direction.
35.
36.
37. Introduction
⦿ 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
38. ⦿Strain calculated in three orthogonal
planes- representing longitudinal, radial,
circumferential contraction.
⦿Negative strain- shortening of segment.
⦿Positive strain- lengthening of segment
44. ⦿ 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 rotation
⦿ Torsion - Twist divided by the vertical distance
between the apex and base and is expressed as
degrees/cm.
45.
46. Applications
Myocardial Strain Patterns In Undifferentiated LV
Hypertrophy.
Cardio-oncology-Early detection of
chemotherapy induced cardiotoxicity.
Aortic Stenosis.
Amylodosis
Valvular heart disease
Other chembers
47. Myocardial Strain Patterns In Undifferentiated LV
Hypertrophy
EF TO GLS RATIO >4.1
RRSR –AVERAGE APICAL/AVERAGE BASAL
+AVERAGE MID STAIN = >1
NORMAL DIFFERENCE FROM BASE TO APEX
IS APP -2%.
48.
49. CAD- Myocardial ischemia, Myocardial
infarction, Myocardial viability
⦿ Reduction in strain by 2D STE more objective
and accurate than the traditional visual
method of assessing WMA.
⦿ Post systolic thickening (deformation)by radial
strain correlates with the severity of ischemia.
⦿ To differentiate transmural from
subendocardial infarction- lower
circumferential strain in the former
50. Differentiation of Athlete’s Heart from
Hypertrophic Cardiomyopathy
Athlete’s Heart Hypertrophic
Cardiomyopathy
Normal longitudinal and other
types of strain
Decreased longitudinal strain
Increased LVEDV
Decreases after deconditioning for 3
months.
Decreased LVEDV
No change with deconditioning.
Increased LV twist. Delayed LV untwisting.
Increased early LA strain rate. Reduced LA strain and
strain rate