Method of reducing ultrasound signal ambiguity during fetal monitoring

• US 9,107,584 B2
• Filed: 07/29/2011
• Issued: 08/18/2015
• Est. Priority Date: 08/02/2010
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips N.V.
• Inventors: Wohlschlager, Markus, Franck, Christoph
• Primary Examiner(s): Roy, Baisakhi
• Application Number:
  US13/812,151
• Publication Number:
  US 20130123637A1
• Time in Patent Office: 1,481 Days
• Field of Search: 600/407, 600/438, 600/453, 600/455, 600/483
• US Class Current: 1/1
• CPC Class Codes: A61B 8/02 Measuring pulse or heart rate
• CPC Class Codes: A61B 8/0866 involving foetal diagnosis; pre-natal or peri-natal diagnosis of the baby
• CPC Class Codes: G01S 7/526 Receivers

Abstract

The present invention relates to a method and a device for fetal cardiac monitoring. For improving ultrasonic monitoring, the number of periodic signals, such as signals caused by the fetus and the mother, is assessed and the time window of the signal demodulation is adapted if more than one periodic signal is assessed.

Claims

1. A method of fetal cardiac monitoring, comprising the steps of:

a) receiving an ultrasound signal reflected by a fetus;

b) demodulating the signal received in at least one time window with a specific duration;

c) assessing whether at least one time window contains more than one periodic signal; and

d) reducing the duration of at least one time window in the case of more than one assessed periodic signal to generate an adapted time window;

wherein steps a) to d) are repeated until step c) assesses the adapted time window to have only one periodic signal.

2. The method according to claim 1, further comprising:

e) calculating a fetal cardiac signal on the basis of the demodulated signal from the adapted time window having only one periodic signal.

3. The method according to claim 1, wherein in step d) the duration of the time window is reduced by setting the ending point of the time window earlier.

4. The method according to claim 1, wherein the adapted time window is reset to the original time window in step d), if in the preceding step c) no periodic signal is assessed in the adapted time window.

5. A non-transitory computer program enabling a processor to carry out the method of claim 1.

6. A method of fetal cardiac monitoring, comprising the steps of:

a) receiving an ultrasound signal reflected by a fetus and splitting the signal into at least one measurement path and at least one reference path;

b) demodulating one part of the signal received in a first time window with a specific duration in the measurement path and another part of the signal received in a second time window with a specific duration in the reference path;

c) assessing whether the second time window of the reference path contains more than one periodic signal; and

d) adapting the duration of the first time window of the measurement path in the case of more than one periodic signal assessed in the second time window of the reference path; and

wherein steps a) to d) are repeated with the adapted or non-adapted first time window.

7. The method according to claim 6, wherein the second time window has a longer duration than the first time window.

8. An ultrasonic fetal cardiac monitoring device, comprising:

an ultrasonic transducer for generating an ultrasound signal and for collecting an ultrasound signal reflected by a fetus; and

one or more processors electrically connected to the ultrasonic transducer, and configured for;

receiving a signal from the ultrasonic transducer;

demodulating the received signal in at least one time window with a specific duration;

assessing whether at least one time window contains more than one periodic signal; and

reducing the duration of at least one time window in the case of more than one assessed periodic signal to generate an adapted time window;

wherein the receiving, the demodulating, the assessing and the reducing are repeated until it is assessed that the adapted time window has only one periodic signal.

9. The device according to claim 8, wherein the device comprises an amplifier for amplifying the ultrasound signal collected by the ultrasonic transducer.

10. The device according to claim 8, wherein the device comprises at least one filter.

11. The device according to claim 8, wherein the device comprises an analog to digital converter for converting the demodulated signal.

12. The device according to claim 8, wherein the device comprises a signal conditioner for conditioning the demodulated signal.

13. The device according to claim 8, wherein an ambiguity detector and a cardiac signal calculator are both connected to a signal conditioner, wherein the ambiguity detector is connected by a window controller to a demodulator.

14. An ultrasonic fetal cardiac monitoring device, comprising:

an ultrasonic transducer for generating an ultrasound signal and for receiving an ultrasound signal reflected by a fetus,

a demodulator for demodulating the received signal in at least one time window with a specific duration,

an ambiguity detector for assessing whether at least one time window contains more than one periodic signal,

a window controller for adapting the duration of at least one time window of the demodulator upon a signal from the ambiguity detector indicating more than one periodic signal, and

a fetal cardiac signal calculator for calculating a fetal cardiac signal on the basis of at least one demodulated signal,

wherein the device comprises a signal splitter for splitting the received signal into a measurement path and a reference path, wherein both the measurement path and the reference path comprise a demodulator and a signal conditioner connected to the demodulator, wherein the fetal cardiac signal calculator is connected to the signal conditioner of the measurement path, and wherein the ambiguity detector is connected to the signal conditioner of the reference path and via the window controller to the demodulator of the measurement path.