METHOD OF REDUCING ULTRASOUND SIGNAL AMBIGUITY DURING FETAL MONITORING

• US 20130123637A1
• Filed: 07/29/2011
• Published: 05/16/2013
• Est. Priority Date: 08/02/2010
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Wohlschlager, Markus, Franck, Christoph
• Granted Patent: US 9,107,584 B2
• Time in Patent Office: Days
• US Class Current: 600/453
• 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) adapting the duration of at least one time window in the case of more than one assessed periodic signal;

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

2. The method according to claim 1, 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;

h) 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.

3. The method according to claim 2, wherein the second time window has a longer duration than the first time window.

4. The method according to claim 1, wherein a fetal cardiac signal is calculated on the basis of at least one demodulated signal.

5. The method according to claim 1, wherein in step d) the duration of the time window is reduced.

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

7. 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.

8. A computer program enabling a processor to carry out the method of claim 1.

9. 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 (30) 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.

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

11. The device according to claim 9, wherein the device comprises at least one filter.

12. The device according to claim 9, wherein the device comprises an analog to digital converter for converting the demodulated signal.

13. The device according to claim 9, wherein the device comprises a signal conditioner for conditioning the demodulated signal.

14. The device according to claim 9, wherein the ambiguity detector and the cardiac signal calculator are both connected to the signal conditioner, wherein the ambiguity detector is connected by the window controller to the demodulator.

15. The device according to claim 9, 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.