Embolus Size Estimator for Peripheral Blood Vessels - Theoretical Considerations

摘要

Microemboli are small gaseous bubbles or solid particles which can block small blood vessels. The possible consequences are ischemia or infarct. Physicians detect microemboli flowing in a blood vessel using ultrasound Doppler flow meters. Such examinations are long-lasting and analysis of recorded data is subjective. The only result is the number of microemboli and there is no information about their size or material. The assessment of the associated risk is thus difficult. Embolus size estimation could improve accuracy of diagnosis. Such estimator should be insensitive to microemboli material type or attenuation of ultrasound in tissue. A method to estimate size of solid microembolic elements was proposed and its feasibility was theoretically analyzed. The obtained results suggest that proposed embolus size estimator is insensitive to ultrasound beam shape, tissue attenuation, amplification of received signal and weakly sensitive to material type of microemboli. The indication on how to select measurement frequencies and angles were provided. The presented method is dedicated to monitoring peripheral vessels i.e. a. femoralis, a. tibialis, because of the measurement setup.