The document discusses automated calculations of left ventricular ejection fraction (LVEF) using 2-D echocardiography images, highlighting its accuracy, methodologies (ellipsoidal and stacked disk), and applications in clinical settings. It explains the cardiac cycle phases (systole and diastole) and the importance of LVEF as a key indicator of cardiac health. Additionally, it covers image analysis techniques for accurate volume estimation and the significance of echocardiography in assessing cardiac function.

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Automated Ejection Fraction Calculations
from B-Mode (2-D) Echocardiography
Suhas Deshpande, Member, IEEE, IEEE-EMBS, CSULB, suhassd@ieee.org
 Heart is basically the pump for the human circulatory
Abstract—Left Ventricular Ejection Fraction can be estimate system. It provides the blood and thus oxygen and vital
to acceptable accuracy using 2-D echocardiography images. 2-D nutrients from lungs to various parts of the body. The heart
Echocardiography due to its portability and versatility is used in physiologically consists of four parts- left and right ventricles
emergency operations and ICUs. The estimation of LVEF can and left and right Auricles. Right Auricle collects the
help the physians to get apriori knowledge of the start of
deoxygenated blood from all the parts of the body. Right
conditions such as Coronary heart disease or Cardiomyopathy.
The ejection fraction can be evaluated by using the simson’s
ventricle pumps the deoxygenated blood to lungs. The
approximation for calculating the volume of the 2-D image. The Oxygenated blood reaches the left auricle and is pumped out
two methods tried here are Ellipsoidal and Stacked disk method. to other parts of the body through left ventricle via the aorta.
Thus the left ventricle performance describes the amount of
Index Terms—Ejection Fraction, Echocardiography, Systole, oxygen reaching the body.
Diastole
A. Systole
Systole is a phase of the cardiac cycle in which the heart
I. INTRODUCTION muscle contracts in a coordinated manner in response to a
complex endogenous autonomic physiologic electrical
H eart diseases are by far the most common cause of deaths
in US. In majority of the cases the death can be
prevented if there is a priori knowledge of some of the cardiac
stimulus. Systole results in driving blood flow out of the heart
and into the body and lungs. All four chambers of a human
heart undergo systole and diastole in a timed fashion so that
functions. Left ventricular Ejection Fraction is one of the
blood is propelled forward and backward through the
most important cardiac function which gives a good idea
cardiovascular system.
about the cardiac problem in advance. The LVEF can be
estimated by using a 2D echocardiography, which is portable
and versatile, is widely used in emergency, operating, and B. Diastole
intensive care department. Diastole is the period of time when the heart fills with
blood after systole. Ventricular diastole is the period during
which the ventricles are relaxing, while atrial diastole is the
II. FUNCTIONING OF HEART period during which the atria are relaxing. During ventricular
diastole, the pressure in the ventricles drops from the peak in
systole to below the pressure in the left atrium, causing the
mitral valve to open. This forces the blood from the atrium to
flow into the ventricle.
III. ECHOCARDIOGRAM
Echocardiography is an ultrasound test done for cardiac
assessment. The ultrasound waves are transmitted by a
transmitter. The ultrasound waves are reflected off the cardiac
walls. The computer maps the ECHOs on a line & then takes
another sample on a different line thus building up a 2D
picture approx 50 times a second. A pseudo image can be
prepared on the basis of the received reflected ultrasound
wave. This image, echocardiogram or ECHO can be used in
diagnostics of the cardiac system. Since the system is simple
in design and easy to carry it is very popular with the cardiac
diagnosis.
Fig 1. Heart Anatomy and Blood Flow through Heart
The frequencies commonly used 2-10MHz are much
higher than the audible range of 2-18KHz. Higher

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frequencies allow better resolution. Lateral resolution of a 5 B. Parasternal Long Axis
MHz is 2 mm compared to 3mm of 3MHz whilst axial
resolution varies from 0.5 mm to 1 mm) but tissue penetration
is poorer.
The Echocardiogram can be optained by imaging the heart
by positioning the sensor at different position. Transthoracic
view and Parasternal view are commonly used. Trans
oesophagal view can be obtained by placing the sensor on a
catheter inside the oesophagus.
Fig 4. Parasternal Long Axis (Image:National University of
Singapore)
The transducer is placed in just to the left of the mid to
upper sternal border. The right ventricular outflow region, the
ventricular septum and the left atrium and ventricular are
well visualized. This is one of the best views to obtain an M
Mode and hence information on cardiac function.
Fig 2. Acoustic Windows (Image University of Minnesota) C. Parasternal Short Axis
The 2D pictures are taken from the various echo windows
and give "standard views" to build up a complete picture of
the cardiac anatomy. Not all chambers are visible in every
view.
A. Apical 4 Chamber
Fig 5. Parasternal short Axis (Image:National University of
Singapore)
From the parasternal long axis view the transduce is rotated
90˚ to point towards the left shoulder. The aorta and coronary
artery origins are seen well in cross section.
Fig 3. Apical 4 Chamber view (Image:National University of D. Subcostal View
Singapore)
The transducer is held at the apex of the heart and angled This is a good view to see lovely images - especially in
towards the right shoulder. The 4 chambers are readily seen babies as no ribs or lung tissue obscures the view. The atrial
and both the mitral and tricuspid valves. If the transducer is septum is particularly well seen. Unfortunately the
angled anteriorly then the aorta is also visualized. This view transducer is the furthest from the heart and in older children
is shows the ventricular septum well to look for septal defects. and adults the distance may be too great to allow detailed
imaging.

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mitral valve closure; (c) as the instant of maximum cardiac
dimension. End-systole is given by the instant preceding
mitral valve opening or by the instant of minimum cardiac
dimension.
IV. EJECTION FRACTION
One of the key indicators of cardiac health is measurement
of left ventricular (LV) volume and ejection fraction (EF).
The ejection fraction determines the amount of blood pumped
out of the ventricles with each cycle of the ECG.
The most commonly applied models for the computation of
the LV internal volume are derived from that proposed by
Simpson. According to the criterion usually called
Fig 6. Subcoastal view (Image:National University of “Simpson‟s rule,” the LV is approximated by a stack of
Singapore) circular (or elliptical) disks whose centers are all in the major
axis. The most important measurement of ventricular
function is the LVEF (Left Ventricle Ejection Function),
E. Arch View which is given by the normalized (nondimensional) difference
between End-Diastolic Volume (EDV) and the End-Systolic
Volume (ESV), both generally computed according to
Simpson‟s rule. The simple formula defining this parameter
is
LVEF =
A. Stacked disk method
In stacked disk method the left ventricle is divided into „n‟
Fig 7. Arch view (Image:National University of Singapore) disks. The number of disks „n‟ can be varied to get the
required accuracy level. Each disk diameter is matched with
This is obtained by sliding the transducer towards the upper the respective contour of the left ventricle. Each disk is
sternal edge and suprasternal notch. It allows the ascending considered to be an ideal circular shape. The LV volume is
aorta, arch and neck vessels to be imaged. estimated using the Simpson‟s equation
F. Importance
Echocardiography is the preferred method for the
documentation of cardiac function at rest. In particular, 2D
Transthoracic Echocardiography (TTE), because of its
portability and versatility, is widely used in emergency,
operating, and intensive care departments. The TTE
technique provides numerous highly significant quantitative
parameters. In fact, it has been demonstrated that cardiac risk
increases significantly when the values of certain parameters
are abnormal. A number of these parameters are connected to
properties of the LV. Thus LV dimensions, volumes, and wall Figure 8. Stacked disc method for Ejection Fraction
thickness are widely used in clinical practice and research. estimation
With regard to LV volume quantification, the most important
windows are the apical (4-chamber view and the 2-chamber
view) and the left parasternal (short-axis view at the papillary Stacked-disk estimation of LV volume
muscle level). The various quantitative parameters are = ((first disk area + last disk area)/2
generally measured at end-diastole and at end-systole. End- + ∑in-1 disk area) x d
diastole can be defined in three ways: (a) as the onset of the d = disk spacing; n = number of disks; disk are = *r2
QRS Complex in the ECG signal; (b) as the instant after

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This is one of the basic volume estimation methods for most VI. SIMULATION & RESULTS
of applications.
The image for the evaluation of Ejection Fraction was
B. Ellipsoid method. obtained from Phillips Ultrasound after email conversation
with Dr. David Hull and Tibor Duliskovich. The images are
extracted at end systole and end diastole.
Fig 9. The dimensional evaluation Ellipsoid method (a) ( b)
Fig 10. Echocardiography images (a) End Diastole (b) End
The left ventricle is assumed to be an ellipsoid. The volume Systole
of an ellipsoid can be given by the equation :
The images were processed using the Mathworks
V = 4π/3 abc ( a,b,c are the ellipsoid radii of the LV) MATLAB©. The grayscale image was cropped to the region
of interest, which is the Left Ventricle for this case. The
In case of the Left ventricle a and c are measured from the cropped image was filtered using a median filter, unmasking
Apical 4 chamber view. c can be measured from the filter for contrast enhastment. Edge detection was done to get
corresponding perpendicular plane (short axis view). It can be the edge of the binary image.
assumed to be equal to D and the formula becomes
V = π/6 LD2
V. IMAGE ANALYSIS AND FILTERING
The echocardiogram is an image created from the
ultrasound waves. Thus the recreated image contains a lot of
noise. Image is very blurred and often it is impossible to read
the image except for a trained people. Many filtering
techniques have been developed to filter the image to be (a) (b)
suitable for estimating the left ventricular volume. Fig 11. Filtered image (a) Systolic (b) Diastolic
The Echocardiogram images generally have all frequencies
within a short region. It is useful to spread the frequency
spectrum throughout the range of the image. This helps in
thresholding to detect the region of interest (left ventricle in
this case). Histogram equalization is a technique to spread out
the frequencies in an image. Unsharp masking is a technique
used to enhance the image perception by actually using a
blurring effect. Technically, an unsharp mask is generally a
linear or nonlinear filter that amplifies high-frequency
components. Order statistical filters use the statistical data in
the specific order of the mask to filter the image. The median
filter, each pixel will be replaced by the median of the
neighboring pixels. Max(min) filter can be used to chek th
maximum(minimum) value in the neighboring pixels. Fig 12. Edge detection (a) Systolic (b) Diastolic
Averaging filter finds the mean of the neighboring pixels.
The image is preferably converted to a binary image to The edge detection came out to be a somewhat ellipsoid left
determine the dimensions of the image. This is done by first ventricle in both systole and diastole.
contrast enhancing and then thresholding of the image.

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Imaging: From Nano to Macro - Proceedings, vol. 2006, pp. 97-100, 2006.
[6] http://www.med.nus.edu.sg/paed/resources/cardiac_thumbnail/
Table 1. Ejection Fraction by Slotted disk method, Ellipsoid investigations/echo.htm
method and provided by Phillips [7] http://www.vhlab.umn.edu/atlas/echotutorial/echotutorial1.shtml
Method Slotted Disk Ellipsoid Original [8] http://rwjms1.umdnj.edu/shindler/imageproc.html#edgefin3.m
EF(Phillips)
Ejection 55.1% 61.45% 54%
fraction
The End Systolic Volume and End Diastolic value was
calculated by calculating the pixels in the image. The pixels
along one axis give the dimension of the left ventricle along
that axis. For e.g to calculate the disk diameter the pixels
along the x axis were calculated. The number of disks was
chosen to be 20.
VII. CONCLUSION
The ejection fraction calculated using the two methods is
around 54% which is the EF measured by the Phillips
Ultrasound (Data imprinted on the image). There are still
some discrepancies in the code and the image. The apical 2
chamber view would have been a better choice for the
estimation of the volume of LV volume. This is because the
ROI is the left ventricle. The repeatability is poor as the final
result depends much on the cropping of the image to get the
ROI as the left ventricle. There are some problems regarding
the cropping the image to the ROI. If the cropping border
touches the left ventricular edge, the estimation goes wrong.
This is because the ROI is not evaluated precisely due to
opening in the region. There are several discontinuities (black
subregions) present in the filtered image. These subregions
need to be removed to get an accurate EF measurement. A
better filtering approach may remove the discontinuities.
ACKNOWLEDGMENT
I am thankful to Dr. Lobodzinsky for conducting the course
of Digital Image Processing which helped me to base my
study in the project. Further I would like to thank Dr. David
Hull and Tibor Duliskovich from Phillips Radiology
department to provide assistance in providing the images for
the project.
REFERENCES
[1] Arthur J. Vander, “Cardiovascular Physiology,” Human Physiology: Th e
Mechanisms of Body Function, 9th edition: MGH, pp 375-399, 2004
[2] Bonita Anderson, “Two dimensional echocardiographic measurements
and calculations,” Echocardiography: The Normal Examination and
Echocardiographic Measurements: Wiley, pp 96- 103, 2002
[3] T. L. Szabo, "Improving ejection fraction estimation for 2d ultrasound
using a computer-generated cardiac model," Proceedings - IEEE Ultrasonics
Symposium, pp. 1757-1760, 2008.
[4] U. Barcaro, "Automatic computation of left ventricle ejection fraction
from dynamic ultrasound images," Pattern Recognition and Image Analysis, vol.
18, pp. 351-358, 2008.
[5] M. Jolly, "Assisted ejection fraction in B-mode and contrast
echocardiography," 2006 3rd IEEE International Symposium on Biomedical