Multiple frequency doppler ultrasound probe
View Patent ↗A method of measuring blood flow through a blood vessel is provided using a single quasi-continuous mode probe that can support multiple frequencies without increasing the probe tip size. A plurality of elements are provided in the probe tip. Each element emits ultrasound waves using a long pulsed signal with each element having a different resonant frequency. Each element also receives ultrasound energy in a continuous mode. A selector is manually controlled by a practitioner to select the active element. The output may take a variety of forms. For example, the output may be printed, displayed, recorded to a memory, and/or played through a speaker or headset.
1. An ultrasound probe, comprising:
a first element circuit, including a first element that emits a first transmit signal toward an object and receives a first reflected signal from the object, the first transmit signal including a first center frequency and a first pulse repetition frequency; and
a second element circuit, including a second element that emits a second transmit signal toward the object and receives a second reflected signal from the object, the second transmit signal including a second center frequency and a second pulse repetition frequency; and
a switch, coupled to the first and second element circuits, to selectively activate and deactivate the first and second element circuits and to operatively couple the activated element circuit to an output, the switch including a first position that activates the first element circuit and deactivates the second element circuit, and a second position that deactivates the first element circuit and activates the second element circuit.
2. The ultrasound probe of claim 1 wherein the first center frequency is in the range from about 2 megahertz (MHz) to about 10 MHz.
3. The ultrasound probe of claim 1 wherein the first center frequency is about 2 megahertz (MHz) and the second center frequency is about 3 MHz.
4. The ultrasound probe of claim 3 wherein the second pulse repetition frequency is in the range from about 5 kilohertz (kHz) to about 6 kHz.
5. The ultrasound probe of claim 4 wherein the first pulse repetition frequency is about 5.3 kHz.
6. The ultrasound probe of claim 1 wherein the first center frequency is about 5 megahertz (MHz) and the second center frequency is about 8 MHz.
7. The ultrasound probe of claim 6 wherein the second pulse repetition frequency is in the range from about 62 kilohertz (kHz) to about 63 kHz.
8. The ultrasound probe of claim 7 wherein the first pulse repetition frequency is about 62.5 kHz.
9. The ultrasound probe of claim 1 , wherein the first element and the second element are piezoelectric crystals.
10. The ultrasound probe of claim 9 wherein a shape of the piezoelectric crystals is selected from the group consisting of a semicircular shape and a rectangular shape.
11. The ultrasound probe of claim 9 further comprising a tip, wherein the first element and the second element are mounted adjacent to each other in the tip.
12. The ultrasound probe of claim 11 wherein the first element and the second element are mounted without a backing material.
13. The ultrasound probe of claim 1 , wherein the second center frequency is different than the first center frequency.
14. A method of determining a characteristic of an object, the method comprising:
selecting one of a plurality of switch positions including a first switch position that activates a first element circuit and deactivates a second element circuit, and a second switch position that deactivates the first element circuit and activates the second element circuit;
generating, by the activated element circuit, a pulsed signal;
emitting, from the activated element circuit, energy toward an object;
receiving, by the activated element circuit, a reflected signal from the object;
processing the received signal to determine a characteristic of the object; and
outputting the characteristic of the object.
15. The method of claim 14 wherein the object is a blood vessel and the characteristic of the blood vessel is a blood flow velocity.
16. The method of claim 14 wherein receiving the reflected signal is continuous.
17. An ultrasound system, comprising:
a first element circuit, including an oscillator, a transmit amplifier, a piezoelectric element, a receive circuit, a mixer and a receive amplifier, that generates a first transmit signal including a first center frequency and a first pulse repetition frequency;
a second element circuit, including an oscillator, a transmit amplifier, a piezoelectric element, a receive circuit, a mixer and a receive amplifier, that generates a second transmit signal including a second center frequency and a second pulse repetition frequency; and
a switch, coupled to the first and second element circuits, to selectively activate and deactivate the first and second element circuits and to operatively couple the activated element circuit to an output, the switch including a first position that activates the first element circuit and deactivates the second element circuit, and a second position that deactivates the first element circuit and activates the second element circuit.
18. The ultrasound system of claim 17 wherein the output is selected from the group consisting of a display, a printer, a speaker, an audio headset, and a memory.
19. The ultrasound system of claim 17 wherein the first element circuit generates the first transmit signal only if the switch activates the first circuit.
20. The ultrasound system of claim 17 wherein the second element circuit transmits the second transmit signal only if the switch activates the second element circuit.
21. The ultrasound system of claim 17 , wherein the second center frequency is different than the first center frequency.