Application of TimeFrequency Analysis Diagnostic Doppler Ultrasound DATE

Application of Time-Frequency Analysis : Diagnostic Doppler Ultrasound DATE： 2013/12/12 REPORTER：林宗民

Outline 1. Basic Concepts 2. Doppler Signal 3. Spectral Doppler 4. Doppler Image(Color Doppler, Power Doppler) 5. Conclusion

Ultrasound u. Longitudinal wave u. Frequency > 20 KHz u. Diagnosis Ultrasound： 1~13 MHz u. Velocity ： l 343 m/s in air l 1540 m/s in tissue l 6420 m/s in aluminum http: //i 299. photobucket. com/albums/mm 288/wasi 1 42/Biological%20 classification/waves. jpg

Doppler Effect u. Frequency shift due to relative movement. u. Doppler frequency： fd = f – f 0

Ultrasound Image – B mode u. Brightness-mode u. Backscattered image u. Tomography http: //content. answcdn. com/main/content/img/Mc. Graw. Hill/Encyclope dia/images/CE 757525 FG 0010. gif

Doppler Signal u. Doppler Signal, xd(t) = i. FT{ fd = fr – ft} u. Typically ~k. Hz in diagnosis Doppler ultrasound. Continuous Wave Pulse Wave Measuring the time-varying Doppler shift Transmitting several pulses and sampling received signals

Doppler Signal Continuous Wave u. Transmitting monochromatic wave. Transmitted signal spectrum

Doppler Signal Continuous Wave u. Transmitting monochromatic wave. u. Received signals from moving tissue plus static tissue. fstatic fmoving Received signal spectrum

Doppler Signal Continuous Wave u. Transmitting monochromatic wave. u Received signals from moving tissue plus static tissue. u. Demodulation and filtering. fstatic fmoving Doppler signal spectrum

Doppler Signal Continuous Wave u. Transmitting monochromatic wave. u Received signals from moving tissue plus static tissue. u. Demodulation and filtering. fmoving Doppler signal spectrum

Doppler Signal Pulse Wave u. Transmitting several pulses. u. Multi-gate sampling.

Doppler Signal Pulse Wave u. Transmitting several pulses. u. Multi-gate sampling. u. Doppler signal

Spectral Doppler (Sonogram) u. Continuous wave or Pulse wave u. Combining B-mode ultrasound with pulsed wave Doppler u. STFT has been commonly used. Unbalanced Sampling with ↑ 50% overlap. http: //en. wikipedia. org/wiki/File: Spectral. Doppler. A. jpg

Simulation Analysis

Simulation Analysis STFT Bessel Distribution Choi-Williams Distribution Cone distribution

Simulation Analysis STFT Bessel Distribution Choi-Williams Distribution Cone distribution

Color Doppler u. Combining B-mode and Doppler signal. u. Pulse Wave Multi-gate system. u Velocity and direction of blood flow are the desire information. u 2 spatial dimension + 1 temporal dimension amount computation. u Auto-correlation method for calculating average frequency.

Power Doppler u. Combining B-mode and Doppler signal. u. Pulse Wave Multi-gate system. u. Total power of Doppler signal. u. Indicating the flow density information. u. Not T-F analysis

Conclusion u. Image is 3 -D signals. It’s not proper to use T-F analysis. u. Spectral Doppler is 1 -D signals. T-F analysis has been used to measure the blood flow. u. In practice, diagnosis signals are more complex than simulated signals, and more noise. Statistic methods are used.

Reference u“The Difference Between Colour Doppler Velocity Imaging and Power Doppler Imaging, ” W. N. Mc. Dicken and T. Anderson, Eur J Echocardiography(2002)3, 240– 244 u“Time-Frequency Analysis for Doppler Ultrasound signals, ”陳宗銓, http: //djj. ee. ntu. edu. tw/Tutorial_Time. Frequency%20 Analysis%20 for%20 Doppler%20 Ultrasound%20 Signals. docx. u“Physics and instrumentation of Diagnostic Medical Ultrasound, ” PETER FISH, 1990. u“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. u“The Physical Principles of Doppler and Spectral Analysis, ” Peter N. Burns, Ph. D, J Clin Ultrasound 15567 -590. Novemberl. December 1987.