Hewlett-packard Company

Alan P Greenstein

John N Dukes

A system for tracing uterine contraction is disclosed. The system comprises a probe and an electronics module. The electronics module includes a drive circuit and an output section having a frequency counter. The output section also includes a strip-chart recorder driven by a frequency-to-voltage converter. The probe includes an electro-mehanical transducer which is driven at resonance by the action of the drive circuit. When the probe contacts the abdomen of a pregnant subject, changes in the mechanical impedance of bodily tissue during a contraction affect the resonant frequency of the probe and thus the frequency output by the drive circuit. This frequency can be read directly from the frequency counter and recorded on the strip-chart so that contractions can be traced.

Uterine contraction detection

A system for tracing uterine contraction is disclosed. The system comprises a probe and an electronics module. The electronics module includes a drive circuit and an output section having a frequency counter. The output section also includes a strip-chart recorder driven by a frequency-to-voltage converter. The probe includes an electro-mechanical transducer which is driven at resonance by the action of the drive circuit. When the probe contacts the abdomen of a pregnant subject, changes in the mechanical impedance of bodily tissue during a contraction affect the resonant frequency of the probe and thus the frequency output by the drive circuit. This frequency can be read directly from the frequency counter and recorded on the strip-chart so that contractions can be traced.

An ultrasound system, employable for medical imaging, includes an electronics module and a probe. The probe includes a body, a transducer, a driver, a window and coupling fluid. The electronics module includes a transmitter which generates transmission pulses which are converted by the transducer to ultrasound pulses and a receiver which analyzes electrical signals resulting from the conversion of ultrasonic reflections received by the transducer. The electronics module controls delays in the transmission and reception between individual elements of the annular phased array transducer to control focussing. The driver provides for mechanical steering of the transducer. The coupling fluid provides for ultrasonic coupling between the transducer and the window and the subject while permitting the steering movement of the transducer. The coupling fluid is a mixture of 1-Butanol in Glycerol. The attenuation of that mixture can be adjusted without impairing velocity matching by adding suitable amounts of 2-Hydroxyethyl ether.

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Menlo Park, CA, United States of America

Alan P Greenstein