| 摘要 |
A method and apparatus for distinguishing ultrasound signals returned from bubbles and particles moving in a fluid from signals due to ultrasound transducer motion monitors the receiving ultrasound signal for signals which are of much larger amplitude than the signals observed when no gas bubbles or particles are present. When a large amplitude event is detected, the maximum amplitude of the forward flow signal (that is, the positive frequency portion of the power spectrum) is compared to the maximum amplitude of the reverse flow signal (negative frequency portion of the power spectrum). If these maxima are significantly different in amplitude, the event is counted as a bubble. If the maximum amplitudes of the forward and reverse flow signals are comparable, the event is classified as a motion artifact. Displays of the spectra are marked whenever an event is counted as an air or particulate emboli so as to call attention to the event and, optionally, to generate an audible or visual alarm.
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