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Application of Time-Frequency Analysis : Diagnostic Doppler Ultrasound
DATE : 2013/12/12
REPORTER :林宗民
Outline1. Basic Concepts
2. Doppler Signal
3. Spectral Doppler
4. Doppler Image(Color Doppler, Power Doppler)
5. Conclusion
UltrasoundLongitudinal waveFrequency > 20 KHzDiagnosis Ultrasound : 1~13 MHzVelocity :343m/s in air1540m/s in tissue6420m/s in aluminum
http://i299.photobucket.com/albums/mm288/wasi142/Biological%20classification/waves.jpg
Ultrasound Image – B modeBrightness-mode
Backscattered image
Tomography
http://content.answcdn.com/main/content/img/McGrawHill/Encyclopedia/images/CE757525FG0010.gif
Doppler Signal, xd(t) = iFT{ fd = fr – ft}
Typically ~kHz in diagnosis Doppler ultrasound.
Continuous Wave Pulse WaveMeasuring the time-varying
Doppler shiftTransmitting several pulses and
sampling received signals
Doppler Signal
Doppler SignalContinuous Wave
Transmitting monochromatic wave.
Received signals from moving tissue plus static tissue.
Received signal spectrum
fstatic
fmoving
Doppler SignalContinuous Wave
Transmitting monochromatic wave.
Received signals from moving tissue plus static tissue.
Demodulation and filtering.
Doppler signal spectrum
fstatic
fmoving
Doppler SignalContinuous Wave
Transmitting monochromatic wave.
Received signals from moving tissue plus static tissue.
Demodulation and filtering.
Doppler signal spectrum
fmoving
Spectral Doppler (Sonogram)
Continuous wave or Pulse wave
Combining B-mode ultrasound with pulsed wave Doppler
STFT has been commonly used.Unbalanced Sampling with ↑50% overlap.
http://en.wikipedia.org/wiki/File:SpectralDopplerA.jpg
2, ( ) f
nS Qj pm
t fp nS Q
X n m w nS p x p e
Simulation AnalysisSimulated Doppler signal.
Using STFT, Cohen’s class Distribution.Choi-Williams DistributionBessel DistributionCone-Shape Distribution
0 0.5 1 1.5 2 2.5 3-4000
-3000
-2000
-1000
0
1000
2000
3000
4000
Time (s)
Am
plitu
de (
mv)
Time (s)
Fre
quen
cy (
Hz)
Power Spectral Density S(t,f)
500 1000 1500 2000 2500 3000
50
100
150
200
250
300
350
400
450
500
Simulation Analysis
Time (s)
Fre
quen
cy (
Hz)
0.05 0.1 0.15 0.2 0.25 0.30
500
1000
1500
2000
2500
Time (s)
Fre
quen
cy (
Hz)
0.05 0.1 0.15 0.2 0.25 0.30
500
1000
1500
2000
2500
Time (s)
Fre
quen
cy (
Hz)
0.05 0.1 0.15 0.2 0.25 0.30
500
1000
1500
2000
2500
Time (s)
Fre
quen
cy (
Hz)
0.05 0.1 0.15 0.2 0.25 0.30
500
1000
1500
2000
2500
STFT
Conedistribution
Bessel Distribution
Choi-Williams Distribution
Simulation Analysis
Time (s)
Fre
quen
cy (
Hz)
0.05 0.1 0.15 0.2 0.25 0.30
500
1000
1500
2000
2500
Time (s)
Fre
quen
cy (
Hz)
0.05 0.1 0.15 0.2 0.25 0.30
500
1000
1500
2000
2500
Time (s)
Fre
quen
cy (
Hz)
0.05 0.1 0.15 0.2 0.25 0.30
500
1000
1500
2000
2500
Time (s)
Fre
quen
cy (
Hz)
0.05 0.1 0.15 0.2 0.25 0.30
500
1000
1500
2000
2500
Conedistribution
Bessel Distribution
Choi-Williams Distribution
STFT Choi-Williams Bessel Distribution Cone Distribution0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Method
Cor
rela
tion
coef
ficie
nt
STFT
Color DopplerCombining B-mode and Doppler signal.
Pulse Wave Multi-gate system.
Velocity and direction of blood flow are the desire information.
2 spatial dimension +1 temporal dimension amount computation.
Auto-correlation method for calculating average frequency.
Power DopplerCombining B-mode and Doppler signal.
Pulse Wave Multi-gate system.
Total power of Doppler signal.
Indicating the flow density information.
Not T-F analysis
ConclusionImage is 3-D signals. It’s not proper to use T-F analysis.
Spectral Doppler is 1-D signals. T-F analysis has been used to measure the blood flow.
In practice, diagnosis signals are more complex than simulated signals, and more noise. Statistic methods are used.
Reference“The Difference Between Colour Doppler Velocity Imaging and Power Doppler Imaging,” W. N. McDicken and T. Anderson, Eur
J Echocardiography(2002)3,240–244
“Time-Frequency Analysis for Doppler Ultrasound signals,” 陳宗銓 , http://djj.ee.ntu.edu.tw/Tutorial_Time-Frequency%20Analysis%20for%20Doppler%20Ultrasound%20Signals.docx.
“Physics and instrumentation of Diagnostic Medical Ultrasound,” PETER FISH, 1990.
“Evaluation of fetal arrhythmias from simultaneous pulsed wave Doppler in pulmonary artery and vein,” Julene S Carvalho, Federico Prefumo, Valentina Ciardelli, Shanthi Sairam, Amarnath Bhide, Elliot A Shinebourne, 2007.
“The Physical Principles of Doppler and Spectral Analysis,” Peter N. Burns, PhD, J Clin Ultrasound 15567-590. NovemberlDecember 1987.