Dr Ramachandra Barik,
First, ultrasound can be directed as a beam
It obeys the laws of reflection and refraction
It is poorly transmitted through a gaseous
medium and attenuation occurs rapidly,
especially at higher frequencies.
The amount of reflection, refraction, and
attenuation depends on the acoustic
properties of the various media through which
the ultrasound beam passes.
Within soft tissue, velocity of sound is
fairly constant at approximately 1,540
m/sec (or 1.54 m/msec, or 1.54 mm/µsec).
Wave length(in millimeters) = 1.54/f,
where f is the transducer frequency (in
higher frequency ultrasound has less
penetration compared with lower
The loss of ultrasound as it propagates
through a medium is referred to as
Attenuation has three components:
absorption, scattering, and reflection.
Attenuation always increases with depth
and is also affected by the frequency and
Attenuation may be expressed as “half-
value layer”or “half-power distance”which
is a measure of the distance that
ultrasound travels before its amplitude is
decreased to one half its original value
As a rule of thumb, the attenuation of
ultrasound in tissue is between 0.5 and
The velocity and direction of the
ultrasound beam as it passes through a
medium are a function of the acoustic
impedance of that medium.
Acoustic impedance (Z, measured in
rayls) is simply the product of velocity (in
meters per second) and physical density
(in kilograms per cubic meter).
The phenomena of reflection and
refraction obey the laws of optics and
depend on the angle of incidence as well
as the acoustic mismatch.
Small differences in velocity also
These properties explain the importance
of using an acoustic coupling gel during
This is primarily due to the very high
acoustic impedance of air.
Specular echoes are produced by reflectors
that are large relative to ultrasound
wavelength. Eg: endocardial and epicardial
surfaces, valves, and pericardium.
Targets that are small relative to the
wavelength of the transmitted ultrasound
produce scattering, and such objects are
sometimes referred to as Rayleigh scatterers.
Scattered echoes provide the substrate for
visualizing the texture of gray-scale images.
The term speckle is used to describe the
Most commercial transducers employ
ceramics, such as ferroelectrics, barium
titanate, and lead zirconate titanate.
Dampening (or backing) material, which
shortens the ringing response of the
piezoelectric material after the brief
excitation pulse. An excessive ringing
response lengthens the ultrasonic pulse
and decreases range resolution.
At the surface of the transducer,
An important feature of ultrasound is the
ability to direct or focus the beam .
The proximal or cylindrical portion of the
beam is referred to as the near field or
When it begins to diverge, it is called the
far field or Fraunhofer zone.
Maximizing the length of the near field is
an important goal of echocardiography.
The ultrasound beam is both focused
and steered electronically, beam
manipulation can be achieved through
the use of phased array transducer.
By adjusting the timing of excitation and
adjustments in the timing allow the beam
to be steered through a sector arc,
resulting in a two-dimensional image.
electronic transmit focusing of the beam
Focusing concentrates the acoustic
energy into a smaller area, resulting in
increased intensity .
By increasing beam intensity within the
near field, the strength of returning signals
is enhanced. An undesirable effect of
focusing is its effect on beam divergence
in the far field
across the lateral
dimensions of the
It is customary to
measure the beam
width at its half
amplitude or intens.
At high gain settings,
the weaker portion of
the ultrasound beam
is recorded and
Resolution has at least two components:
spatial and temporal.
Spatial resolution - smallest distance that
two targets can be separated .
Commercial echographs have repetition
rates between 200 and 5,000 per second.
M-mode , pulse repetition rates of
between 1,000 and 2,000 per second are
For two-dimensional imaging, repetition
rates of 3,000 to 5,000 per second are
necessary to create the 90-degree sector
Because all the pulses are devoted to a
• Requires more than one position.
• Tilting pt to left improves ultrasound
• Rt lat decubitus-record aortic flow &
• Subcostal imaging
• Suprasternal notch
• Sitting position
• Mid portion & base of lv ,both leaflets of
MV ,AV ,AO root ,LA &RV.
• imaging plane is aligned parallel to long
axis of lv.
• Reduced endocardial definition & wall
motion analysis difficult.
• Medial angulation of the scan plane – RA
& RV seen.
• one of the most important components of
quantitation of ventricular function.
• Qualitative and quantitative data derived from
echocardiography, e.g., LV dimensions and wall
thickness, can influence patient management and
serve as potent predictors of outcomes
• Chronic stable coronary artery disease, there is a
consistent relationship between heart size and
• The same applies to patients without heart failure.
• Framingham Heart Study patients without a history
of heart failure or myocardial infarction, LV size (by
M-mode echocardiography) was an important
predictor of subsequent risk of heart failure.
• M-mode line perpendicular to long
axis of the heart and immediately
distal to the tips of the mitral leaflets
in thePLAX view
• diastolic measurements
septal wall thickness, the
LV internal diameter at end diastole
(LVIDd) and posterior wall thickness.
In systole, the LV systolic diameter(LVIDs)
• clockwise rotation of 90 degrees
• Pts lateral wall I placed to the observer”s
• LV is displayed as if viewed from apex
• Apical level
• Papillary muscle level -
• Mitral valve level- Precise recording of
mitral orifice in pts with MS.
-Basal level- aortic annulus, AV, coronory
ostia, LA, TV, RVOT, PV & prox pa.
regarded as clock face- LMCA at 4 & RCA
-with slight superior angulation-bifurcation
• Apical 4 chamber-After location of apical
window ,all 4 chambers are optimally
visualised when ful excursion of MV & TV
leaflets occurs & true apex is seen.
-false tendons of LV & moderator band
of RV are normal variants.
–crux of heart.
• Apical 5 chamber –tilt the transducer into
a shallower angle
• Apical 2 chamber- rotating the transducer
CCW approx 60 deg.
Similar orientation to RAO
angiographic view LA
APPENDAGE IS VIEWED.
• Apical long axis view –transducer rotated
CW 60 similar to PLAX.
LV walls &
ultrasound beam are parallel.
Quantifying aortic valvular & subvalvular
obstruction including HOCM.
• beam is oriented perpendicular to long
axis of LV
• better endocardial definition
• septal defects are better delineated.
• Only view that visualises superior portion
• proximity of RV free wallto the
• IVC & hepatic veins are viewed.
Far Posterior tilt to visualise pulmonary veins
• One of the most significant developments of
the last decades was the introduction of 3-
dimensional (3D) imaging and its evolution
from slow and labor-intense off-line
reconstruction to real-time volumetric imaging
• The major proven advantage of this
technique is the improvement in the accuracy
of the echocardiographic evaluation of
cardiac chamber volumes.
• Another benefit of 3D imaging is the realistic
and unique comprehensive views of cardiac
valves and congenital abnormalities
• The major breakthrough that allowed
quality real-time imaging was the
development of a microbeam former
• When the entire crystal of the transducer
head is sampled or covered with
elements, the transducer is a dense array
• The microbeam former is required for this
arrangement to provide a communication
of all of the approximately 3000 elements
to the ultrasound system
• Transducer design
• 2 D Matrix array of transducer elements
helps generate the third dimension
• The significant innovation that actually
allows steering is making the elements
electrically independent from each other
• This allows generating a scan line that
varies azimuthally and elevationally
• Modern 2D
therefore consist of
elements that steer
a scan line left and
right as well as up
• Beam forming in three spatial dimensions
1. Beam forming constitutes the steering and focusing
of transmitted and received scan lines
2. Significant portion of the beam steering is done
within the transducer in highly specialized integrated
3. The main system steers at coarse angles, but the
transducer circuits steer in fine increments in a
process termed microbeam forming
4. Summing is the act of combining raw acoustic
information from each element to generate a scan
line and by summing these in a sequence (first in
the transducer and then subsequently in the system)
• There are two major black and white modes run
in an electronically steered 3D system
• Live mode where the system scans in realtime
• Gating, this time only four to eight beats, allows
a technique to generate wider volumes while
maintaining frame rate
• 3 D modes
1.Live 3D mode–instantaneous
4.3D color Doppler–gated
• Display of 3D information
1.A 3D data set consists of bricks of pixels
called volume elements or voxels
• A process known as cropping can be used
to cut into the volume and make some
• 3D data sets of voxels are turned into 2D
images in a process known as volume
• All 3D echocardiography is subject to the
laws of physics.
• Artifacts such as ringing, reverberations,
shadowing, and attenuation occur in three
and two dimensions.
• . The constraints of a 3D image are
(2) 3D volume size,
(3) Image resolution.
• 1) Direct evaluation of cardiac chamber volumes without
the need for geometric modeling
• 2) Noninvasive realistic views of cardiac valves and
congenital abnormalities , helpful for showing a variety of
pathologies and assessing the effectiveness of surgical
or percutaneous transcatheter interventions
• 3) Direct3D assessment of regional LV wall motion
aimed at objective detection of ischemic heart disease at
rest and during stress testing ,as well as quantification of
systolic asynchrony to guide ventricular
• 4) 3D color Doppler imaging with volumetric
quantification of regurgitant lesions shunts ,and cardiac
• 5) Volumetric imaging and quantification of myocardial
• True myocardial motion occurs in three
dimensions, and traditional 2D scanning
planes do not capture the entire motion of
• Quantifying implies segmenting structures
of interest from the 3D voxel set
• 3D quantification of the left ventricle
typically employs a surface- rendered
• This allows accurate computation of
• Most studies have
been done on
about the mitral
has improved with
the advent of 3 D
• B mode echoes from an interface
that changes position will be
seen as echoes moving towards
and away from the transducer.
• If a trace line is placed on this
interface and the resulting trace
is made to drift across the face of
• The resulting display shows
motion of a reflector over
distance and time – a distance
• The change in distance (dy) over
a period of time dt is represented
by the slope of the reflector line
• If this motion pattern is obtained
on moving cardiac structures
then the resulting images
• M-mode echocardiography is use
to evaluate the morphology of
structures, movement and
velocity of cardiac valves and
M-mode at the Mitral Valve
EPSS Measure e point to septal
< 5 mm
d-e Measures the maximum
excusion of the mitral valve
following diastolic opening.
17 to 30 mm
M-mode at the Mitral Valve
Slope Description Normal Value
d-e Measure rate of initial
opening of the mitral valve
in early diastole.
240 to 380
e-f Measures the rate of early
closure of the mitral valve
50 to 180 mm/s
• Flail PMVL
• Fluttering of the AMVL
• Mitral Stenosis
• LA myxoma
B-bump on the
Premature Closure- closure
on or before the onset of the
Systolic anterior motion
of the AMVL
MV Prolapse –
Flail posterior leaflet