Non-invasive blood flow measurements utilizing cardiac cycle synchronization
July 26, 2005. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesMethod of and apparatus for measurement of blood flow using coherent light Duplex ultrasonic imaging system with repetitive excitation of common transducer in doppler modality Directional detection of blood velocities in an ultrasound system Quantitative volume blood flow measurement by an ultrasound imaging system featuring a Doppler modality Measurement of true blood velocity by an ultrasound system Doppler pseudorandom noise velocimeters Ultrasonic doppler flowmeters Noninvasive measurement of blood flow rate utilizing ultrasound Method and system for non-invasive ultrasound Doppler cardiac output measurement Ultrasonic living body tissue characterization system Patent #: 4575799 InventorsAssigneeApplicationNo. 06/730456 filed on 05/06/1985US Classes:600/455, Pulse Doppler73/861.25Reflection or scattering of acoustic wavesExaminersPrimary: Jaworski, Francis J.Attorney, Agent or FirmInternational ClassA61B 8/06 (20060101)AbstractA system for non-invasively determining the amount of blood flow by performing an autoregressive analysis of Doppler shifted acoustical signals resulting from reflected ultrasonic signals from blood cell movement within internal blood vessels. Each cardiac cycle is determined by an analysis of the patient's electrocardiogram signals,and the resulting cardiac cycles are divided into a predefined number of time segments or channels each containing Doppler shifted signals. The autoregressive analysis is then performed over each individual channel to determine reflection coefficients that model the blood flow and a residual energy level that indicates the energy not accounted for by that modeling. The reflection coefficients results result from a linear predictive code analysis, and the term "reflection coefficients" is not used in the customary manner as defined for ultrasonic flow analysis of blood as defining a level of reflected acoustic energy. A power spectrum analysis is then performed utilizing the reflection coefficients and residual energy level for each channel. Then, the power spectra of individual channels of all of the cycles are averaged together producing a group of averaged channels representing the average blood flow through the patient's internal vessel over all of the cardiac cycles. These averaged power spectra for each combined channel are then normalized and displayed on a channel-by-channel basis utilizing different colors to represent the different power levels. The utilization of different colors greatly enhances the ability of medical personnel to make diagnostic decisions regarding the amount of blood flow.Other References
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