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PRINCIPLES OF SONOGRAPHY
Frederick W. Kremkau, Ph.D.Professor of Radiologic Sciences
Wake Forest University School of Medicine
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DisclosuresFrederick W. Kremkau
Relevant Financial Relationships: None
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Learning ObjectivesAfter completing this presentation, the learner will be able to:
1. Explain the fundamental principle used in sonographic imaging
2. Describe the image formats used in sonography
3. Describe how echoes are generated
4. List the primary components of a sonographic transducer
5. List the primary components of a sonographic instrument
6. Describe the Doppler effect
7. List the ways in which Doppler information is presented
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Lecture Outline
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A. Imaging PrincipleB. UltrasoundC. TransducersD. InstrumentsE. Doppler Principle
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SONOGRAPHYsonos: [Latin] “sound”ΥραΦειν: [Greek] “to write”
< Image: a representation
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1 scan line1 scan line 5 scan lines
48 scan lines 96 scan lines
192 scan lines
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sector
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• Ultrasound• Transducers• Instruments
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1 second
5 cycles per second
FREQUENCY
Number of per second.
Kremkau Kremkaucycle per second
HeinrichHertz 1890
4
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1 microsecond
5 million hertz
μεγας = large
ULTRASOUND
> 20 kHz
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My favorite frequency is 40,000 Hz.What’s yours?
30 kHz ispopular now.Have you heard it?
SPEED
LIMIT
1.54mm/µs
1.54mm/µs
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A t t e n u a t i o n
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3 MHz17 cm
5 MHz11 cm
7 MHz7 cm
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5
T
1 cm
[2 cm of travel]
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13 μs 1 cm
65 μs 5 cm
130 μs 10 cm
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piezoelectricceramicelements
dampingmaterial
matchinglayers
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3 mm
2 mm
3 mm
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Linear Array
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Convex Array
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Convex Array
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What’s going on in here?
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SIGNALPROCESSOR
IMAGEPROCESSOR
DISPLAYBEAM
FORMER
T
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SIGNALPROCESSOR
IMAGEPROCESSOR
DISPLAYBEAM
FORMER
T
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AMPLIFIER
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SIGNALPROCESSOR
IMAGEPROCESSOR
DISPLAYBEAM
FORMER
T
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amplitude detection
RF
amplitude
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SIGNALPROCESSOR
IMAGEPROCESSOR
DISPLAYBEAM
FORMER
T
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10 x 10pixels
8 x 8pixels= pictureelements
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640 x 476 = 304,640 pixels
99 x 78 = 7,722 pixels
SIGNALPROCESSOR
IMAGEPROCESSOR
DISPLAYBEAM
FORMER
T
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12 3 64 56 17 1810 50
768
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M
depth
t i m e
BEAMFORMER
T
SIGNALPROCESSOR
BEAMFORMER
T
SIGNALPROCESSOR
IMAGEPROCESSOR
BEAMFORMER
T
SIGNALPROCESSOR
IMAGEPROCESSOR
DISPLAYBEAM
FORMER
T
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Doppler Principles
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Audible Sounds
Color-Doppler Display
Spectral Display
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• Ultrasound• Transducer• Instrument• Anatomic Imaging• Motion and Flow Imaging
References1. Kremkau FW: Sonography principles and instruments, ed 9, Philadelphia, 2016, Elsevier/Saunders.2. Hedrick W: Technology for diagnostic sonography, St. Louis, 2013, Elsevier/Mosby.3. Gibbs V, Cole D, Sassano A: Ultrasound physics and technology, Edinburgh, 2009, Elsevier/Churchill.4. Hagen-Ansert S: Textbook of diagnostic sonography, ed 8, St. Louis, 2017, Elsevier/Mosby.5. Baun J: Ob/Gyn sonography, ed 2, Pasadena, 2016, Davies.
I love sonography!
PHRED'SPHUN
PHYSICS