Basics of Transthoracic

Echocardiogram1 March 2013

PGI Chandigarh Dr Sarvesh Natani

SONAR( sound navigation & ranging) in 1800’s

Ingle Edler& Carl Hertz 1st recorded echo 1950 in sweden

CW 1963 Real time scanner 1965 PW 1970 1974 1st duplex pulse doppler scanner 1980 color doppler.

History

Wave Property

Frequency (f) & wavelength (λ) Propogation speed 1540m/s 20- 20000 Hz 1-10 million ( 1- 10 MHz) in echo Upto 30 MHz for intracoronary imaging Shorter λ higher f better resolution reduced

penetration

Basic Physics

B mode or basic grey scale Presets for echo automatically default to

higher frame rates Depth: start deep then decrease n focus on

area of importance. try to get area of intrest in upper 2/3

Gain: How machine listens to returning echoes. gain amplifies returning echo n image is brighter.

Can be over all or at depth called TGC.

Knobology

Zoom Focus : optimises lateral resolution at given

depth Tissue Hamonics; Frame rate etc

Knobology

M mode: visualize moving thing in 1 dimension eg IVC, cardiac valves.

Doppler: uses frequency shift of sound waves to measure velocity

Color flow Pulse wave Continuous wave

Other Modes

Tran thoracic EchoA standard echocardiogram is also known as a Trans thoracic echocardiogram (TTE), or cardiac ultrasound. The subject is asked to lie in the semi recumbent position on his or her left side with the head elevated.The left arm is tucked under the head and the right arm lies along the right side of the bodyStandard positions on the chest wall are used for placement of the transducer called “echo windows”

Described by size n shape of footprint. Linear, curvilinear and phased array Phased array probe ;an electronically

steered beam in a close array, generating an image that comes from a point and is good for getting between ribs such as in cardiac ultrasound.

F 1-10MHz

Probe/ transducer

Echo Probe

1. Imaging requires the use of intercostal acoustic windows.2. Probes with small “footprints.”3. Phased or microconvex arrays are utilized for this reason.4. Imaging in adults; lower frequencies (typically 2-4 MHz).5. Curvilinear probes can be used to image the heart, especially in the

subxiphoidview.However,

Parasternal Apical Subcoastal Suprasternal

Echo Windows

Translation Rotation Angulation Heal- toe

Probe Movements

Parasternal Long-Axis View (PLAX)

Transducer position: left sternal edge; 2nd – 4th intercostal spaceMarker dot direction: points towards right shoulderMost echo studies begin with this viewIt sets the stage for subsequent echo viewsMany structures seen from this view

Parasternal Short Axis View (PSAX)Transducer position: left sternal edge; 2nd – 4th intercostal spaceMarker dot direction: points towards left shoulder(900 clockwise from PLAX view)By tilting transducer on an axis between the left hip and right shoulder, short axis views are obtained at different levels, from the aorta to the LV apex.Many structures seen