Download Two dimensional Speckle Tracking Echocardiography An overview

Review articles
A Journal of Cardiological Society of India, Kerala Chapter
Two dimensional Speckle
Tracking Echocardiography
An overview
AK Abraham*
One of the main demands on echocardiography was
the evaluation of regional and global left ventricular
function. In the early days of echocardiography the M
Mode based ejection fraction was considered to be the
main tool for this purpose. Eventually this was found
to be totally inaccurate in most cases, so much so, no
less a person than Feigenbaum declared publicly that
he does not do ejection fractions any more. There
haven attempts to identify other parameters for LV
function assessment as time progressed. Ejection
fractions
based on 3 dimensional volume
determinations added the accuracy, but was
constrained by the increased time and effort needed.
Doppler
based tissue velocity based studies ,
especially the mitral annular velocities ,offered some
relief. But this was again
criticized as inaccurate because
of the inherent problems of the
insonation angle discrepencies.
Strain and strain rate studies
offered some hope, but this was
also based on Doppler technology
which was again not totally
acceptable.
In early 2000, the 2 D based
speckle tracking concept gained
prominence. This overcame the
problem of Doppler velocities
being used to measure
displacement. Speckle Tracking
Echocardiography (STE) is a
unique imaging technique
where the motion of ultrasonic
interference patterns called
“speckles”are monitored to derive strain patterns.
Regional STRAIN is a dimensionless measurement
of deformation , expressed as percentage change
from the original dimension. (1) During a cardiac
cycle , stretching and shortening occur in the
myocardium during systole and diastole. Essentially
this is a deformation from the original state. This is
known as the Langrangian Strain, and is used by the
speckle tracking technology. The end diastolic
myocardial dimension is taken as the reference
point against which the deformation is analysed (2)
Studies of LV myocardial contraction, mainly by
Partho Sen Gupta and Bijoy Khanderia from Mayo
clinic, have shown twist or torsional deformation
Long axis view and graph in normal LV function
*Head, Dept of Cardiology, Indira Gandhi Co-op Hospital, Kochi
KHJ
Kerala Heart Journal
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Review articles
A Journal of Cardiological Society of India, Kerala Chapter
the longitudinal direction.
According to Choi et al, a
strain value less than – 17.9
% was correlated with severe
3 vessel disease.(6)
2. Myocardial infarction
Myocardial infarctions result
in changes in LV functions
like ejection fraction an
regional wall abnormalities.
STE studies have been
shown abnormal strain
patterns in such situations.
These strain patterns have
been found to be correlated
to the severity and extent of
infarcted areas. (7,8) . These
results have been of prognosis value also.
Long axis and graph in LV Dysfunction
occurs during ejection, which when viewed from the
apex appears as clockwise rotation at the apex and
counterclockwise at the base. (3). To describe these
movements, terms such as twist, rotation and torsion
are used. But by convention, “rotation “ refers to the
rotation seen in short axis vies of LV. The term
“torsion” to the difference in rotation that occurs
along the longitudinal axis. The ability to quantify
these data was made possible with the application of
speckle tracking technology. This has made a
tremendous stride in the evaluation LV function
especially in various stages of myocardial ischemia.
The accuracy of speckle tracking has been compared
with the existing techniques like microsonometry ,
tagged MRI and tissue Doppler strain measurements
and has been found to correlate significantly with all
these methods.(4,5)
3.
Stress echocardiography
One of the major difficulties faced in stress
echocardiography was the
problem of
quantification of the ventricular deformation
imaging. The inter observer values were
notoriously variable. Attempts were made to use
tissue velocity imaging , but was constrained by
it's inability to study radial contractions. A
beakthrough in stress echo quantification has
been attempted with the use of STE in systolic
and diastolic phases of the cardiac cycle, using
longitudinal, radial and circumferential
directional values. (9)
In 2D speckle strain examinati
ons, the commonly used parame
ters are (i) Peak systolic strain,
(ii))Strain rates, (iii) time to peak
measurements, (iv) circumferential
strains (v)diastolic measurements.
Using these studies in various
clinical states haven undertake.
1.
Coronary artery disease
In myocardial ischemia,
the longitudinal strain
values , especially in the
endocardium
shows
evidence of hypoperfusion .
This would be translated
into attenuated values in
Radial view and graph in LV Dysfunction
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KHJ
Kerala Heart Journal
Review articles
A Journal of Cardiological Society of India, Kerala Chapter
all 3 directions, as
expected. The vaues can be
utilized to assess the
beneficial effect of
treatment or worsening, on
repeated exams. (13)
8.
Radial view in normal LV function
4.
Revascularization
The role of STE in revacularization is to identify
the damages during balloon occlusion, viability
of tissues and the impact of successful procedure.
5.
Valvular heart disease
Even severe valve disease like aortic stenosis
can remain asymptomatic for a long time.
However , subclinical LV dysfunction can occur
early in the disease.STE can identify these
abnormalities if done serially and can be made
use of in determining the time of surgery
6.
LV hypertrophy
One of unique advantages of STE is in the
identification of the nature and causes of LV
hypertrophy in different conditions. Though
there are different opinions , it is generally
agreed that in the LVH found in in athletes the
strains are high. (10)
In the LVH in
hypertension the longitudinal strain shows
reduction, probably due to the associated
fibrosis. (11) This has to be evaluated in the light
of radial strains which often are paradoxical.
The other condition with LVH is hypertrophic
cardiomyopathy.
Here again the universal
opinion is that the STE values are diminished
reflecting the myocardial fibre disarray found in
the pathology of the disease. (12) STE can also
identify the coexisting diastolic dysfunction
also which the hallmark of this condition.
7.
Dilated cardiomyopathy
In dilated cardiomyopathy , strain is reduced in
KHJ
Kerala Heart Journal
Stress cardiomyopathy
Cardiomyopthy , known as
Takotsubo cardiomyopathy,
is attributed to be stress
related and is usually
reversible. STE can play a
significant role in the
diagnosis , because of the
regional strain patterns
not related to any coronary
distribution. STE also can
be used to monitor the
recovery patterns.(14)
9.
Pericardial disease
Specific STE patterns have been described in
various stages of pericardial disease.
In
constrictive percarditis, the circumferential
strain is impaired while the longitudinal might
be preserved. Conversely, in restrictive
conditions like amyloidosis, it is the longitudinal
strain that is reduced. This feature can be of
significant in doubtful cases.(15)
10. Evaluation of heart failure
STE studies have played a major role in the
understanding 0f myocardial mechanics in
cardiac failure. Contrary to the older model of
separation of systolic and diastolic
LV
dysfunction, the new insight is to take these as
expressions of a continuum of events. STE
studies have revealed overlapping values in
diastolic and systolic hear failure syndromes.(16,17)
11. Resynchronization Therapy
The increasing acceptance of resynchronization
therapy sought newer modalities for the
evaluation LV dysfunction. Since the technology
was based mainly on the radial contractility
STE with it's unique ability to evaluate radial
and circumferential functions became the focus
of intense interest. Newer indices were
developed using STE
to identify
ideal
candidates for CRT and responders. (18,19) STE
was also used to monitor the prognosis as well.
12. Cardicac involvement in systemic diseases
One of the major fallouts of STE was the
identification of subtle cardiac involvement I n
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Review articles
A Journal of Cardiological Society of India, Kerala Chapter
diabetes. Longitudinal and global strain changes
have been noted (20,21) This would be of great
importance in the context of concerns of the
complications of drugs like glitazones which are
incriminated in LV dysfunction, and which may
lead on to cardiac failure , The other area of
interest would be the cardiotoxicity induced by
anthracycline like molecules
while being
treated for malignancy . Early detection using
STE can be of help in altering treatment.
Personal experience
In the department of cardiology SRE studies have
been undertaken for the past one year, using Philips
iE 33 ultrasound machine. There was a learning
curve and it continues. There was also the factor of
regular software upgrades which contributed
which have contributed to accuracy of results.
2.
D' Hooge J, Heimdal A, Jamal F, Kukulski T,
Bijnens B, Rademakers F, et al .Regional strain
rate measurements by cardiac ultrasound :
principles, implementation
and limitations.
Eur J Echocardiogr 2000; 1: 154-70.
3.
Sengupta PP, Tajik AJ, Chandrasekaran K,
Khandheria BK. Twist mechanics of the left
ventricle: principles and application. JACC
Cardiovasc Imaging 2008;1: 366-76.
4.
Amundsen BH, Helle-Valle T, Edvardsen T,
Torp H, Crosby J, Lyseggen E, et al. Noninvasive
myocardial strain measurements by speckle
tracking echocardiography: validation against
sonomicrometry and tagged magnetic
resonance imaging JAm Coll Cardiol 2006;
47:789-93
5.
Notomi Y, Lysyansky P, Seter RM, Shiota T,
Popovic ZB, Martin- Miklovic MG, et al.
Measurements of ventricular torsion by two
dimensional ultrasound speckle tracking
Imaging. J Am Coll Cardiol 2005, 45:203-41
6.
Choi JO, Cho SW, Song YB, Cho SJ,Song BG,
Lee SC, et al. Longitudinal 2D strain at rest
predicts the presence of left main and three
vessel coronary artery disease in patients
without regional wall motion ad normality. Eur J
Echocardiogr 2009; 10:695-701.
7.
Bertini M, Mollema SA, Delgado V, Antoni ML, Ng
AC, Holman ER, et al. Impact of time to
reperfusion after acute mycordial infarction on
myocardial damage assessed by left ventricular
longitudinal strain. Am J Cardiol 2009;104:480-5.
8.
Park YH, Kang SJ, Song JK, Lee EY, Song JM
,Kang DH, et al. Prognostic value of longitudinal
strain after primary reperfusion therapy in
patients with anterior wall acute myocardial
infarction.J Am Soc Echocardiogr 2008; 21:2627.
9.
Hanekom L, Cho GY, Leano R, Jeffriess L,
Marwick TH. Comparison of two dimensional
speckle and tissue Doppler strain measurements
during dobutamine stress echocardiography: an
angiographic correlation. Eur Heart J
2007;28:1294-9
In an analysis of 50 cases, these were our preliminary
observations.
1. In a case of obvious global dysfunction all the STE
values were very low. This denoted that STE can
be an independent index of contractility.
2. In cases of myocardial infarction, the STE values
ranged from normal to abnormal. Further studies
are undertaken to identify the role of
reperfusion.
3. There were cases of angiographically proven 3
vessel disease where the STE values were in the
normal range. We are trying to correlate with
prognosis .
4. Further studies are planned to to identify the
patterns of STE in different states of LVH
5. Serial STE studies would identify the state of LV
myocardium after
medical or invasive
revascularization.
Conclusion
A growing body of evidence suggests that the
LV myocardial status can be assessed with STE to
identify, the current contracitility, which would be
correlated to myocardial micro and macro vascular
blood flow independent of the angiographic scenery.
STE hopefully can address this position apart from
all the other tasks for which it can be employed.
References
1. Abraham TP, Dimaano VL, Liang HY. Role of
tissue Doppler and strain echocardiography in
current clinicial practice. Circulation 2007; 116:
2597-609.
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10. Knebel F, Schimeke I, Schroeckh S, Peters H,
Eddicks S, Schattke S, et al. Myocardial function
in older male amateur marathon runners:
assessments by issue Doppler echocardiography,
speckle tracking, and Cardiac biomarkers. J Am
Soc echocardiogr 2009, 22: 8039.
KHJ
Kerala Heart Journal
Review articles
A Journal of Cardiological Society of India, Kerala Chapter
11. Kan SJ, Lim HS,Choi BJ, Choi SY, Hwang GS,
Yoon MH, et al. Longitudinal strain and torsion
assessed by two dimensional speckle tracking
correlate with the serum level of tissue inhibitor
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