1 March 2013 PGI Chandigarh Dr Sarvesh Natani.
-
Upload
clyde-jacobs -
Category
Documents
-
view
217 -
download
0
Transcript of 1 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
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
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 Echo
A 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 body
Standard 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 Long-Axis View (PLAX)
Transducer position: left sternal edge; 2nd – 4th intercostal space
Marker dot direction: points towards right shoulder
Most echo studies begin with this view
It sets the stage for subsequent echo views
Many structures seen from this view
Parasternal Short Axis View (PSAX)
Transducer position: left sternal edge; 2nd – 4th intercostal space
Marker 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