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Transfer function analysis of ultrasonic time-intensity measurements
1Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan. paichi@cc.ee.ntu.edu.tw
Ultrasound in Medicine & Biology
|November 5, 2003
Summary
Flow pulsation does not invalidate ultrasonic microbubble contrast measurements for blood flow estimation. A recursive least squares deconvolution technique effectively analyzes transfer functions in both constant and pulsatile flow conditions.
Area of Science:
- Biomedical Engineering
- Medical Imaging
- Fluid Dynamics
Background:
- Time-intensity measurements of ultrasonic contrast microbubbles aid blood flow estimation.
- Compartment models describe microbubble dilution, assuming linear and time-invariant systems for transfer function analysis via deconvolution.
Purpose of the Study:
- To investigate the impact of flow pulsation on time-intensity measurements for blood flow estimation.
- To evaluate a recursive least squares deconvolution technique for transfer function analysis under pulsatile flow conditions.
Main Methods:
- Simulations and experimental studies were conducted.
- Transfer function analysis was performed using a deconvolution technique based on recursive least squares.
- Time-intensity curves of ultrasonic contrast microbubbles were analyzed.
Main Results:
- Flow pulsation generally does not compromise the validity of time-intensity-based blood flow estimation.
- The proposed deconvolution technique effectively performs transfer function analysis for both constant and pulsatile flows.
- This enables transfer function analysis across diverse hemodynamic conditions.
Conclusions:
- Time-intensity measurements remain valid for blood flow estimation even with flow pulsation.
- The developed deconvolution method supports transfer function analysis in various flow states.
- Future applications include brain perfusion estimation using extracranial measurements.