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Medical Review
Two and Three Dimensional
Wall Motion Analysis
Yasuhiko Abe, Hiroyuki Ohuchi, Tetsuya Kawagishi
Toshiba Medical Systems
Yasuhiko Abe
Hiroyuki Ohuchi
Tetsuya Kawagishi
Introduction
Echocardiography is increasingly used as a
tool for analysis of cardiac function and as an
aid to assessment of ischemia, dyssynchrony,
heart failure and other cardiac conditions.
Automatic Cardiac Output Measurement (ACM),
Tissue Doppler Imaging (TDI) and Automatic
Contour Tracking (ACT) have proven useful for
these tasks, but now a new class of solution
utilizing Wall Motion Tracking promises significant
advances.
The validity of cardiac function assessment
using TDI has already been well investigated.
There are potential advantages to using B-Mode
image data to generate the same results but
image quality and processing power limitations
have made this difficult. Now, improved image
quality and new more powerful processing
techniques make it possible to use an evolution
of ACT to track and quantify myocardial
movement in 2D image data and 4D volumes.
Wall Motion Tracking Technology
Two Dimensional Tracking (2DT) is an application of pattern matching technology to Ultrasound Cine data also commonly known as
Speckle Tracking. A template image is created
using a local myocardial region in the starting
frame of the image data. In the next frame an
algorithm searches for the local speckle pattern
that most closely match the template (Fig. 1).
A movement vector is then created using the
location of the template and the matching pattern
in the subsequent frame. Multiple templates
are used to observe movement of the entire
myocardium. The process is then repeated
by creating new templates and observing their
movement in the subsequent frames until the
search
template
Starting frame
Next frame
End systole
Fig. 1 2 Dimensional Pattern Matching
cubic
template
Next Volume
Starting Volume
End Diastole
End systole
Fig. 2 3 Dimensional Pattern Matching
L0
L
Strain =
( L – L0)
L0
X 100 [%]
Fig. 3 Strain Calculation
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Medical Review
End systole
End diastole
L
Lr
Radial
direction
L0
Radial Strain =
( Lr – L 0 )
L0
X 100 [%]
Strain Calculation using Tracking Results
Fig. 4 Strain Calculation with Wall Motion Tracking
Circumferential strain
Radial strain
Longitudinal strain
Transversal strain
Rotation
Fig. 6 Wall motion Parameters in
Apical 4/3/2 Ch image
Fig. 5 Wall motion Parameters in
SAX image
End diastole
End systole
Fig. 7 Parametric Imaging of Strain
L
Longitudinal
strain
Radial
strain
L0
ED
Radial Strain =
Circumferential
strain
a) Conventional Strain
3 Dimensional Strain =
Lr
ES
( Lr – L0 )
L0
( L – L0 )
L0
X 100 [%]
X 100 [%]
b) Radial 3D strain
ED
2
ES
c) Torsion
Fig. 8 Wall motion Parameters in 3D data
entire cardiac cycle has been assessed. This
method does not make use of Doppler information, so there is no Doppler angle dependency.
Cardiac motion is 3 dimensional, so 2DT is
limited because it cannot assess movement in
the 3rd dimension. The same technique used
in 2DT can be applied to 4D data by tracking 3
dimensional cubic templates through the cardiac
cycle (Fig. 2). Three Dimensional Tracking (3DT)1)
is a new application that can be used for regional
Wall Motion Analysis of the entire Left Ventricle.
3DT can be used for real 3D indices (like torsion)
and 3 dimensional wall motion assessment
rather than assessment based on 2 dimensional
projections of motion.
Strain is a measurement of deformation
representing shortening or expansion (Fig. 3).
Because it is not affected by translational motion
of the heart, strain offers a clear advantage over
velocity and displacement for assessment of
myocardial function. Radial, transversal, longitudinal and circumferential strain can be used for
assessment of cardiac motion.
To calculate strain, a pair of points are defined
in the initial frame. In subsequent frames the
movement of the points is calculated using Wall
Motion Tracking. The change in displacement
between the two points is measured and calculated as a percentage of the displacement
between the points in the initial frame. Thus
strain values can be calculated in any frame.
Fig. 4 shows a radial strain calculation for the end
systolic frame.
Strain can be calculated, in different directions,
using components of the displacement. For
example radial strain is the relative change of the
component of displacement perpendicular to the
endocardium in the short axis view. In the short
axis view, radial strain and circumferential strain
can be calculated (Fig. 5). In the apical 4, 3 and
2 chamber views, transversal strain and longitudinal strain can be calculated (Fig. 6).
Fig. 7 shows an example of strain calculated
using 2DT. Strain values of the local myocardium
are color coded and superimposed on the
image. Wall Motion Tracking not only provides
strain values but can also generate rotation,
strain rate and other values.
2DT calculates these values as a projection of
3D motion. But heart motion is 3 dimensional.
3DT can assess this motion in 3 dimensions
and calculates 3 dimensional strain and other
parameters for the whole Left Ventricle (Fig. 8).
For example, calculation of torsion requires the
rotation values of two short axis planes in the
same cardiac cycle and the distance between
the two planes must be known. Both the
imaging of two planes and the measurement of
the distance between the planes is hard to do
with 2D technology.
Circum. Strain
EDV 74.35 mL 0 msec
ESV 29.70 mL 285 msec
EF
60.05 %
Fig. 9 shows an example of strain calculated
using 3DT. 3DT can provide different kinds of
parametric imaging, mapped onto 3 dimensional
wall segments with or without motion vectors
and superimposed on multiplanar reconstructions.
Wall Motion Tracking results can also be
displayed as a Dyssynchrony Imaging (DI) map.
In DI display mode wall motion parameters
(like time to peak strain) are color coded and
displayed on the myocardium. Table 1 shows all
the parameters calculated by 2DT and 3DT and
the parameters which can be used for DI.
10
d) Motion Vectors
on Wire frames
-18
0
Speckle tracking
60
50
40
30
R=0.62
P<0.001
20
10
10
20
30
40
50
60
70
‑20
‑30
‑40
R=0.70
P<0.001
‑50
‑60
‑60
0
0
‑10
80
‑50
‑40
‑30
MRI
‑20
‑10
0
10
MRI
a) Correlation analysis of 2DT
with MRI tagging about
60 segments of 10 volunteer
(Courtesy of Dr. Seo
in Tsukuba University)
10
0
-10
-20
-30
-40
-50
-50
-40
-30
-20
-10
0
10
Segmental strain c by tagged MRI (%)
20
10
0
Mean difference
-10
-20
-40
-30
-20
-10
-22
-24
-26
-28
-30
BASAL
0
Average of strain c by MRI and 3D Echo
0
-20
-30
-10
0
10
20
10
0
Mean difference
-10
-20
-40
-30
-20
-10
r = 0.54
P < 0.0001
10
0
-10
-20
-30
-40
-50
-50
-40
-30
-20
-10
0
10
Segmental strain by tagged MRI (%)
30
-30
APICAL
b) Regional analysis of 3DT
with MRI tagging about
circumferential strain
(Courtesy of Dr. Lima’s group
in Johns Hopkins University)
-10
-20
MID
LV slices
10
-30
technique
MRI
3D Echo
Segmental strain L by tagged MRI (%)
30
-30
-20
0
Average of strain c by MRI and 3D Echo
Difference strain by MRI and 3D Echo (%)
Speckle tracking
70
Segmental strain by 3D Echo (%)
Circumferential strain
80
95% CI CIRCUMFERENTIAL STRAIN ECC
Radial strain
Segmental strain L by 3D Echo (%)
Wall Motion Tracking is useful for the objective
diagnosis of angina4). Fig. 11 shows its application in Stress Echo. The Ischemic region
exhibits decreased radial strain at peak
(Fig. 11a and b). Diastolic Dyssynchrony is still
clearly visualized, 5 minutes after stress. Using
Dyastolic Dyssynchrony, ischemic regions can be
visualized after peak stress when the image is no
longer as affected by heavy breathing and rapid
heart rate. Application of Diastolic Dyssynchrony
in unstable angina with 2DT is reported in ACC
20085).
c) Doughnuts
display of
rotation
Fig. 9 Parametric Imaging of Strain with 3D Tracking
Difference strain c by MRI and 3D Echo (%)
Clinical Applications
End systole
b) 3D wire frame and endo
cardium projection of
3dimensional displacement
Segmental strain c by 3D Echo (%)
Validation efforts for 2D and 3D Wall Motion
Tracking are being conducted by Dr. Lima at
Johns Hopkins University and Dr. Seo at Tsukuba
University using Toshiba’s ArtidaTM. Current
results are shown in Fig. 10. Both 3DT and 2DT
Wall Motion Tracking shows good correlations
with MRI tagging analysis. Wall Motion Tracking
has shown good correlation with conventional
wall motion analysis2) and numerical models 3).
End diastole
Difference strain c by MRI and 3D Echo (%)
Validation
End systole
End diastole
a) MPR Parametric Imaging and Polar Map of circumferential strain
Volume is always assessed simultaneously.
30
Mean = -1.1
SD = ±6.2
20
10
0
Mean difference
-10
-20
-30
-40
-30
-20
-10
0
Average of strain by MRI and 3D Echo
c) Correlation analysis of 3DT with MRI tagging
(Courtesy of Dr. Lima’s group in Johns Hopkins University)
Fig. 10 Validation Results
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Before stress
Immediate after stress
5 min. after stress
a) End systole
Before stress
Immediate after stress
5 min. after stress
b) 30% of Diastole
Wall Motion Tracking is also expected to
contribute to dyssynchrony estimation in CRT 6).
Segmental analysis is preferred for wall motion
assessment. In Fig. 12 a segmental strain over
time graph is displayed. Average values for
each segment are shown. 2 cases are shown in
which peak strain in different segments is at very
different points in the cardiac cycle. Dyssynchrony is easily recognized.
2DT is now quite well studied and is findings its
way into clinical routine. 3DT is generating new
functional information and is at the forefront of
a new area of clinical research into cardiac wall
motion.
Reference
1. US Patent filed, Pub. No.: US2003/0171668A1, (2003);
H. Tsujino, M. Nishiura
2. Usefulness of Automated Quantitation of Regional Left
Ventricular Wall Motion by a Novel Method of Two Dimensional Echocardiographic Tracking, Am J Cardiol Vol. 98,
Issue 11, 1531-1537 (2006);
K. Ogawa, T. Hozumi, K. Sugioka, Y. Matsumura,
Left coronary artery
Right coronary artery
(#1: 99% stenosis)
c) Angio images
M. Nishiura, R. Kanda, Y. Abe, Y. Takemoto, M. Yoshiyama,
J. Yoshikawa
3.Accurate Detection of Regional Contraction Using Novel
Fig. 11 Detection of Ischemia
(Courtesy of Dr. Ishii in Kansai-Denryoku Hospital)
3-Dimensional Speckle Tracking Technique, JACC Vol. 51,
No. 10 (Supplement A) 903-253, A116 (2008);
Y. Abe, T. Kawagishi, H. Ohuchi, T. Takeguchi, M. Nishiura
4. Detection of Postischemic Regional Left Ventricular
Diastolic Dyssynchrony after Exercise-Induced Ischemia
in Patients with Stable Effort Angina by Using Strain Image
Derived From 2D Speckle Tracking, JASE Vol. 20, No. 5
Abstracts 561 (2007);
K. Ishii, T. Sakurai, K. Kataoka, M. Imai
a) with Transversal strain
(Courtesy of Dr. Gorcsan
in University of Pittsburg)
b) with Circumferential strain
(Courtesy of Dr. Seo
in Tsukuba University)
5. Noninvasive Diagnosis of Acute Coronary Syndrome
Among Patients with Chest Pain by Echocardiographic
Detection of Postischemic Regional Left Ventricular
Fig. 12 Dyssynchrony Estimation
Diastolic Dyssynchrony using Strain Image Derived from
2D Speckle Tracking, JACC Vol. 51, No. 10 (Supplement A)
Wall Motion Parameter
DI Parameter
(2D Tracking for SAX)
SAA Tracking
SAx Tracking
SAB Tracking
(2D Tracking for Apical
approach)
4Ch Tracking
2Ch Tracking
3Ch Tracking
3D Tracking
Radial Strain
Radial Strain Rate
Radial Displacement
Radial Velocity
Circumferential Strain
Circumferential Strain Rate
Rotation
Rotation Rate
Longitudinal Strain
Longitudinal Strain Rate
Longitudinal Displacement
Longitudinal Velocity
Transversal Strain
Transversal Strain Rate
Transversal Displacement
Transversal Velocity
3Dimentional Strain
3Dimentional Displacement
Radial Strain
Radial Displacement
Longitudinal Strain
Longitudinal Displacement
Circumferential Strain
Rotation
Twist
Torsion (from basal)
Regional Torsion
Radial Strain
Radial Displacement
Circumferential Strain
Longitudinal Strain
Longitudinal Displacement
Transversal Strain
Transversal Displacement
M. Kawanami
6.Validation of Novel Echocardiographic Speckle Tracking
Radial Strain To Assess Ventricular Dyssynchrony:
Comparison with Angle Corrected Tissue Doppler Strain
Imaging, JACC Vol. 49, No. 9 (Supplement A) 806-8,100A
(2007);
M. Tanabe, M. S. Suffoletto, M. R. Pinsky, J. Gorcsan, III
Longitudinal Displacement
Table 1: Wall motion Parameters provided by WMT
4
901-280, A104 (2008);
K. Ishii, T. Nagai, T. Sakurai, M. Imai, T. Suyama,
*Artida is trademark of Toshiba Medical Systems Corporation.
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