Phase series echography with prior waveform distortion for evaluating posterior waveform distortion.
We describe a pulse-echo ultrasound method for measuring nonlinear waveform distortion. First, two artificially distorted ultrasound pulses, one of which is transformed into the other by using a linear transform, are prepared prior to the measurement. The linear relationship does not hold for nonlinear propagation. Second, different initial-phase versions of the two pulses are separately transmitted to a specimen one after another, then the echoes with the same turnaround time are placed in order of the initial phase. The placed echoes, called a phase series, have complete information on the posterior waveform distortion. We formulate a waveform distortion index by using these two techniques. The waveform distortion index has a monotonic increasing relationship with the nonlinear parameter B/A. As an example application, we performed tissue characterization of boiled eggs. As a result, egg whites and yolks were clearly distinguished. This method should be useful for biological tissue characterization.
Matani
Ayumu
A
Graduate School of Frontier Sciences, the University of Tokyo. matani@isp.ac
Shigeno
Takayuki
T
D000465:Algorithms; D016477:Artifacts; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D016247:Information Storage and Retrieval / Q000379:methods; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D018617:Ultrasonography, Doppler, Pulsed / Q000379:methods*