An acoustic imaging probe having transducer elements

Abstract

An acoustic imaging probe has an adjustable effective elevation length. The acoustic imaging probe has a transducer element including a plurality of acoustic transducers, and the transducer element is divided into a plurality of sets of adjacent transducers. A processing module controls how many sets contribute to acoustic pulses emitted by the acoustic transducer element during an imaging process, thereby adjusting the effective elevation length of the acoustic imaging probe.

Description

Technical Field

[0001] The present invention relates to the field of acoustic imaging probes, and particularly to an acoustic imaging probe having transducer elements. Background Art

[0002] Acoustic imaging probes including an array of transducer elements are being increasingly used in the medical field. One use case scenario for such an imaging probe is to be used with an intravascular catheter (e.g., IVUS), where the transducer elements are positioned on the catheter (distal end) to be inserted into a blood vessel of a subject. Typically, the transducer elements consist of one or more individual transducers or "drums". Each transducer may include, for example, a piezoelectric transducer (PZT) or a capacitive micromachined ultrasonic transducer (CMUT).

[0003] Typically, the transducer elements emit acoustic pulses (e.g., ultrasonic pulses) and detect the echoes of the emitted acoustic pulses. The echoes can be processed to generate an image. The acoustic pulses can be ultrasonic pulses, and the corresponding generated image is an ultrasonic image.

[0004] There has been a long-standing desire to maximize the resolution of the images generated by an array of transducer elements. In some existing solutions, this is achieved by operating the transducers of each transducer element at a higher center frequency. However, this is at the expense of reducing the penetration depth of the acoustic pulse(s). Some solutions propose to circumvent this problem by enabling the array to operate in a high-resolution mode (reduced penetration) and a high-penetration mode (reduced resolution). In these solutions, the two modes are achieved by shifting the center frequency of the acoustic pulses emitted by the transducers of the array from a high frequency (for the high-resolution mode) to a low frequency (for the high-penetration mode).

[0005] There has been a long-standing desire to provide alternative and / or improved mechanisms for achieving high penetration and / or high resolution. Summary of the Invention

[0006] The present invention is defined by the claims.

[0007] According to an example aspect of the present invention, an acoustic imaging probe is provided.

[0008] The acoustic imaging probe includes: transducer elements, the transducer elements including: a first set of one or more adjacent transducers; and a second set of one or more adjacent transducers, the first set of one or more transducers being adjacent to the second set of one or more transducers, wherein each transducer is configured to controllably emit an acoustic pulse and receive one or more echoes in response to the emitted acoustic pulse.

[0009] The acoustic probe further includes a processing module configured to control the operation of the transducer elements, and the processing module is configured to operate in at least the following operation modes: a first mode, in which the processing module controls the transducer elements such that only the first set of one or more adjacent transducers emits acoustic pulses and the transducers in the first set operate synchronously when emitting the acoustic pulses to provide a first combined acoustic pulse; and a second mode, in which the processing module controls the transducer elements such that both the first set and the second set of one or more adjacent transducers emit acoustic pulses and the transducers in the first set and the second set operate synchronously when emitting the acoustic pulses to provide a second combined acoustic pulse.

[0010] The present invention provides an acoustic probe having one or more transducer elements, which are composed of adjacent transducers, wherein each transducer element has a controllable effective length. The transducers of the transducer elements can be positioned along the same axis, that is, a linear array is formed. In particular, by dividing the transducer elements into two or more adjacent sets (each set can be individually controlled by a processing module), the number of activated sets controls the effective length or size of the transducer elements.

[0011] The inventors have recognized that the penetration depth of the acoustic pulse can be increased by operating more transducers simultaneously, such that the combined acoustic pulse emitted by the transducer element with a larger effective length (compared to a shorter transducer element) has a larger amplitude or a larger sound pressure, thereby obtaining a greater penetration depth. However, the inventors have recognized that increasing the length / size of the transducer element to provide such additional transducer operation will reduce the possible resolution of the acoustic image generated based on the echo of the acoustic pulse. This is because for a longer or larger transducer element, it is more difficult to accurately indicate the precise position of the element that rebounds the acoustic pulse, because as the transducer element increasingly diverges from a point source to a linear / area source (i.e., becomes longer or larger), the precise origin of the acoustic pulse becomes less certain.

[0012] The inventors propose to operate the transducer elements in two modes. In the first mode, the first (relatively small) part of all the transducer elements is controlled to emit a combined acoustic pulse. In the second mode, the second (relatively large) part of all the transducer elements is controlled to emit a combined acoustic pulse.

[0013] In this way, when operating in the first mode, the imaging resolution can be improved (since the effective length / size of the transducer elements is reduced), but at the cost of reduced penetration (since fewer transducers are used). When operating in the second mode, the penetration depth can be increased (since more transducers are used), but at the cost of reduced imaging resolution (since the length / size of the transducer elements is increased). The proposed acoustic probe thus allows for more flexible operation, thereby enhancing its utility and obviating the need to provide separate probes for different penetration / resolution requirements (which would incur additional cost / material requirements and potentially require multiple invasive procedures to properly image the object).

[0014] It would be particularly advantageous to use linear transducer elements, as in linear transducer elements, the effect of changing the elevation length is particularly pronounced. The concept of switching between the first and second modes is particularly applicable to linear arrays, as they are commonly used in scenarios where both high-penetration and low-penetration information is desired (such as in intravascular ultrasound devices).

[0015] Of course, the acoustic imaging probe can include multiple transducer elements, each configured in the manner of the previously described transducer elements.

[0016] In some embodiments, each transducer is configured to require a voltage bias to controllably emit acoustic pulses, and the processing module is configured to: when operating in the first mode, provide a voltage bias only to the first set of adjacent transducers; and when operating in the second mode, provide a voltage bias to both the first set and the second set of adjacent transducers.

[0017] In some examples, the processing module is configured to control the transducer elements such that the center frequency of the first combined acoustic pulse is different from the center frequency of the second combined acoustic pulse.

[0018] In at least one embodiment, the processing module is configured to control the transducer elements such that the center frequency of the first combined acoustic pulse is greater than the center frequency of the second combined acoustic pulse.

[0019] The inventors have recognized that by switching the frequency while switching the number of transducers that emit the combined acoustic pulses, a greater difference between the first and second modes can be provided. Thus, there is a combined effect of switching the frequency and the number of (adjacent) transducers used.

[0020] The processing module can also be configured to operate according to a combination strategy in which the processing module iteratively switches between operating in the first mode and operating in the second mode.

[0021] When operating according to the combination strategy, the processing module can switch between the first mode and the second mode in response to a predetermined number of combined acoustic pulses emitted by the transducer.

[0022] For example, the processing module can switch from the first mode to the second mode (and vice versa) in response to a single combined acoustic pulse emitted by the transducer (i.e., after each combined acoustic pulse) since the last switch. In other examples, the processing module can switch from the first mode to the second mode (and vice versa) in response to a predetermined number (e.g., 2, 3, or 5) of combined acoustic pulses emitted by the transducer since the last switch.

[0023] Of course, the predetermined number of combined acoustic pulses when switching from the first mode to the second mode can be different from the predetermined number of combined acoustic pulses when switching from the second mode to the first mode. For example, the processing module can switch from the first mode to the second mode in response to a first predetermined number of first combined acoustic pulses emitted by the transducer, and can switch from the second mode to the first mode in response to a second predetermined number of second combined acoustic pulses emitted by the transducer. The first predetermined number and the second predetermined number can be different. This embodiment improves the flexibility of imaging and allows for greater control over the power consumption of the imaging probe (since using more transducers increases the power consumption of the imaging array).

[0024] Optionally, the transducer elements further include a third set of one or more neighboring transducers, the third set of one or more transducers being adjacent to the second set of one or more transducers; the processing module is configured such that: when operating in the second mode, only the first set and the second set of one or more neighboring transducers emit acoustic pulses, and the neighboring transducers of the first set and the second set operate synchronously when emitting acoustic pulses to provide a third combined acoustic pulse; and the processing module can also operate in a third mode, in which the processing module controls the transducer elements such that the first set, the second set, and the third set of one or more transducers emit acoustic pulses and the transducers of the first set, the second set, and the third set operate synchronously when emitting acoustic pulses.

[0025] This embodiment improves the flexibility of the imaging probe for finer-grained control of the penetration depth and / or imaging resolution, thus facilitating the selection of an appropriate trade-off for the desired imaging operation.

[0026] Of course, the transducer element can include more than three sets of adjacent transducers, and the processing module can operate in additional modes to control the effective length of the transducer element by appropriately controlling the number of sets of adjacent transducers that can contribute to the combined acoustic pulse.

[0027] Preferably, when operating in any mode, each set in the transducer that contributes to the emitted combined acoustic pulse is adjacent to another set in the sets in the transducer that contribute to the emitted combined acoustic pulse.

[0028] In cases where the processing module has access to more than two modes, the processing module can operate according to different combination schemes that define how the processing module switches between different modes. Those skilled in the art will consider various styles of such combination schemes, but these styles generally include moving between at least three different modes according to a predefined switching scheme.

[0029] In some embodiments, the processing module is adapted to monitor the first set and the second set of the transducer to generate a received signal in response to one or more echo signals received by the first set and the second set of the transducer.

[0030] In some examples, each transducer can include a capacitive micromachined ultrasonic transducer (CMUT). In other examples, each transducer is a piezoelectric transducer (PZT). Those skilled in the art will know other examples of suitable transducers.

[0031] Optionally, the mode in which the processing module operates (or, in relevant cases, the combination strategy according to which the processing module operates) responds to a user input signal. Thus, the user can control in which mode or optionally with which combination strategy the processing module operates.

[0032] The acoustic imaging probe can include a plurality of transducer elements, each transducer element including a first set and a second set of transducers, wherein the processing module is configured to control the operation of each transducer element among the plurality of transducer elements, wherein: when operating in a first mode, the processing module controls each transducer element such that only one or more adjacent transducers' first sets of each transducer element emit acoustic pulses and the transducers of the first set of each transducer element operate synchronously when emitting acoustic pulses to provide a first combined acoustic pulse; and when operating in a second mode, the processing module controls each transducer element such that both the first set and the second set of one or more adjacent transducers of each transducer element emit acoustic pulses and the transducers of the first set and the second set of each transducer element operate synchronously when emitting acoustic pulses to provide a second combined acoustic pulse.

[0033] According to an example of an aspect of the present invention, there is provided a computer-implemented method of controlling an acoustic imaging probe including transducer elements, the transducer elements including: a first set of one or more adjacent transducers; and a second set of one or more adjacent transducers, the first set of one or more transducers being adjacent to the second set of one or more transducers, wherein each transducer is configured to controllably emit an acoustic pulse and receive one or more echoes in response to the emitted acoustic pulse.

[0034] The computer-implemented method includes controlling the transducer elements using at least two modes, the two modes including: a first mode, wherein the processing module controls the transducer elements such that only the first set of one or more adjacent transducers emits an acoustic pulse and the transducers of the first set operate synchronously when emitting the acoustic pulse to provide a first combined acoustic pulse; and a second mode, wherein the processing module controls the transducer elements such that both the first set and the second set of one or more adjacent transducers emit an acoustic pulse and the transducers of the first set and the second set operate synchronously when emitting the acoustic pulse to provide a second combined acoustic pulse.

[0035] Those skilled in the art will appreciate that the computer-implemented method can be appropriately adjusted to perform any embodiment of the present invention described with reference to the embodiments of the disclosed acoustic imaging probe.

[0036] There is also provided a computer program product including computer program code units which, when run on a computing device having a processing system, cause the processing system to perform all the steps of any of the methods described herein.

[0037] There is also provided a processing module configured to perform any of the methods described herein.

[0038] These and other aspects of the present invention will be apparent and elucidated with reference to the (one or more) embodiments described hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] For a better understanding of the present invention and to more clearly show how the present invention may be put into practice, reference will now be made, by way of example only, to the accompanying drawings in which:

[0040] Figure 1 An acoustic imaging device is illustrated;

[0041] Figure 2 is a block diagram illustrating an acoustic imaging probe according to an embodiment of the present invention;

[0042] Figure 3 An acoustic imaging probe is illustrated;

[0043] Figure 4 Illustrates a method according to an embodiment;

[0044] Figure 5 Illustrates a method according to an embodiment; and

[0045] Figure 6 Illustrates an ultrasonic imaging system capable of implementing embodiments of the present invention therein. Detailed Description

[0046] The present invention will be described with reference to the accompanying drawings.

[0047] It should be understood that the detailed description and specific examples, although indicating exemplary embodiments of the apparatus, system, and method, are for illustrative purposes only and are not intended to limit the scope of the present invention. These and other features, aspects, and advantages of the apparatus, system, and method of the present invention will be better understood from the following description, claims, and drawings. It should be understood that these drawings are merely schematic and not drawn to scale. It should also be understood that the same reference numerals are used throughout the drawings to indicate the same or similar parts.

[0048] The present invention provides an acoustic imaging probe having an adjustable effective elevation length. This is achieved by dividing the acoustic transducer elements into a plurality of sets of adjacent transducers and controlling how many sets contribute to the acoustic pulses emitted by the acoustic transducer elements during the imaging process.

[0049] The present invention relies on the recognition that by controlling how many sets of transducers contribute to the acoustic pulses emitted by the transducer elements, a change in the elevation length can be achieved. This results in a tunable acoustic imaging probe that can switch between a high-resolution (low penetration) mode and a high-penetration (low resolution) mode.

[0050] Embodiments of the present invention can be applied to any acoustic imaging system, for example, an ultrasonic imaging system. Particularly advantageous embodiments are applied to intravascular ultrasonic imaging systems.

[0051] Generally, the acoustic pulses are ultrasonic pulses, but other forms of acoustic pulses are possible and contemplated. Thus, in the context of implementing embodiments of the present invention, the term "ultrasonic" can be used in place of the term "acoustic" in the present disclosure (e.g., an ultrasonic imaging probe is an example of an acoustic imaging probe).

[0052] To avoid all doubts, the "transducer element" of the present invention is a (linear) array of one or more individual but adjacent transducers (e.g., PZT or CMUT), which transducers operate and are controlled synchronously. An imaging probe typically includes an array of such transducer elements, which are appropriately controlled to image a desired volume. Alternative labels for transducer elements can be transducer sets, transducer groups, or transducer arrays.

[0053] Figure 1 An example of an acoustic imaging probe 100 is illustrated, where the acoustic imaging probe 100 is an intravascular acoustic imaging probe for an intravascular ultrasound (IVUS) system. Although the exemplary description is related to an intravascular acoustic imaging probe, the present invention is also applicable to other interventional medical devices, such as interventional needles.

[0054] The acoustic imaging probe 100 includes transducer elements 110, which can be a linear array of transducers or "drums" that are controlled by a processing module 120. The processing module 120 can include, for example, an integrated circuit such as an ASIC or FPGA known to those skilled in the art.

[0055] The operation of the acoustic imaging probe 100 will be familiar to those skilled in the art. Briefly, the processing module 120 operates the acoustic imaging probe 100, and the processing module 120 controls the individual transducers of the transducer elements 110 to emit acoustic pulses, and then the transducer elements detect any echoes or reflections of the emitted acoustic pulses. In particular, each transducer of the transducer elements is synchronously controlled to emit an individual acoustic pulse, and when the transducers are operated synchronously, this operation causes the transducer elements to emit a single combined acoustic pulse.

[0056] The control of the transducer elements 110 can be performed in a linear manner (e.g., all transducer elements emit acoustic pulses simultaneously) or in a phased manner (e.g., the transducer elements emit acoustic pulses at different times). The method of appropriately controlling the array of transducers that make up the transducer elements will be obvious to those skilled in the art.

[0057] Then, the processing module 120 processes the signals generated by the transducer elements (in response to the received echoes / reflections) to identify the presence and / or shape / appearance of the (one or more) targets that reflect the emitted acoustic pulses. This information can be further processed to generate an acoustic image, such as an ultrasound image.

[0058] A more complete description of possible processes and systems for generating and processing acoustic pulses (to, for example, generate an acoustic image) will be provided in a later part of the present disclosure.

[0059] Figure 2The elements of an acoustic imaging probe 200 according to an embodiment of the present invention are diagrammatically illustrated in block diagram format.

[0060] The acoustic imaging probe 200 includes a transducer element 210, which is composed of a plurality of transducers 211 arranged in an array. Here, the transducer element 210 is formed as a linear array, but there may be other embodiments (e.g., a two-dimensional array). The transducer element 210 is divided into two sets 215, 216 of one or more adjacent transducers, and these two sets 215, 216 can be recognized as a first set 215 and a second set 216 of transducers. These two sets are adjacent to each other.

[0061] The transducer element 210 can be divided into more than two (adjacent) sets of adjacent transducers, but for ease of understanding, only two sets are illustrated at present.

[0062] The acoustic imaging probe 200 further includes a processing module 220. The processing module 220 is adapted to perform the previously described processes. In particular, the processing module 220 is adapted to control the operation of the transducer element 210 (e.g., using a control line 221). The processing module 220 thus controls the transducer element 210 to emit acoustic pulses.

[0063] As previously mentioned, in a typical imaging probe, each individual transducer in an array of transducer elements is synchronously controlled (e.g., using a control line 221) to emit acoustic pulses. The same control line is provided for each individual transducer so that they can be synchronously controlled. The acoustic pulses output by the array are a combination of all the acoustic pulses synchronously emitted by the individual transducers, thus forming a single "combined acoustic pulse".

[0064] The proposed acoustic imaging probe is slightly modified so that different numbers of transducers 211 can contribute to the combined acoustic pulses emitted by the transducer element 210.

[0065] The processing module 220 is configured to operate in at least two modes.

[0066] In the first mode, the processing module 220 controls the transducer element 210 such that only the first set 215 of transducers contributes to the acoustic pulses emitted by the transducer element 210. In other words, the processing module controls the transducer element such that only one or more adjacent transducers in the first set emit acoustic pulses and the transducers in the first set operate synchronously when emitting acoustic pulses to provide a first combined acoustic pulse. Thus, the second set 216 does not contribute to the combined acoustic pulses in the first mode.

[0067] In the second mode, the processing module controls the transducer elements 210 such that both the first set 215 and the second set 216 of the transducers contribute to the acoustic pulses emitted by the transducer elements. In other words, the processing module controls the transducer elements such that both the first set and the second set of one or more adjacent transducers emit acoustic pulses and the transducers of the first set and the second set operate synchronously when emitting the acoustic pulses to provide a second combined acoustic pulse.

[0068] In this way, the processing module 220 can modify the effective size or length of the transducer elements 210 (when emitting acoustic pulses). This enables the processing module to control the effective elevation length of the transducer elements 210.

[0069] In the illustrated example, each transducer is a capacitive micromachined ultrasonic transducer (CMUT). CMUTs require a voltage bias (such as provided by the voltage bias line 222) for effective operation (such as emitting acoustic pulses, which can contribute to the total acoustic pulses emitted by the transducer elements 210). The response of an unbiased transducer to the reflection / echo of the emitted acoustic pulse can be negligible. In particular, when the CMUTs do not collapse after emitting acoustic pulses, they become insensitive to the received echoes (or any other acoustic transmissions).

[0070] In the illustrated example, the processing module 210 controls which sets of transducers can contribute to the acoustic pulses emitted by the transducer elements 210 by controlling which transducers are provided with a voltage bias. This is achieved by providing separate voltage bias lines for each set 215, 216 of the transducers and controlling which voltage bias lines carry the voltage bias according to the mode of the processing module.

[0071] Accordingly, the processing module 220 can be configured to: when operating in the first mode, provide a voltage bias only to the first set of adjacent transducers; and wherein, when operating in the second mode, provide a voltage bias to both the first set and the second set of adjacent transducers.

[0072] Other methods for controlling which transducers are activated (such as being able to contribute to the acoustic pulses emitted by the transducer elements 210) will be apparent to those skilled in the art. For example, the processing module can provide separate control lines 221 for each set of acoustic elements. This method enables other types of transducers (such as transducers that do not rely on a voltage bias, such as piezoelectric transducers) to be used as the transducers of the transducer elements 210.

[0073] Where possible, it is preferred to use voltage bias lines to control which transducers can contribute to the acoustic pulses emitted by the transducer elements. This is because using separate control lines for control may introduce significantly more interconnections than voltage bias lines (e.g., due to the need for precise control and monitoring of the control lines - compared to voltage bias lines where such precision is less important).

[0074] If the present invention is implemented in an IVUS acoustic probe, using voltage bias lines for control would be particularly advantageous to minimize the size of the IVUS acoustic probe (which is an important consideration for such a probe to reduce patient discomfort and potential harm).

[0075] The processing module 220 may be configured to control the center frequency of the emitted acoustic pulses. The method of controlling the center frequency of the acoustic pulses emitted by an individual transducer will be obvious to a person skilled in the art, for example, by appropriately controlling the signal transmitted through the control line 221 to achieve this.

[0076] Preferably, the processing module 210 is configured to control the transducer elements such that the center frequency of the acoustic pulses ("first combined acoustic pulses") emitted by the transducer elements when operating in a first mode is different from the center frequency of the acoustic pulses ("second combined acoustic pulses") emitted by the transducer elements when operating in a second mode.

[0077] In particular, the processing module is configured to control the transducer elements such that the center frequency of the first combined acoustic pulses is greater than the center frequency of the second combined acoustic pulses. This increases the penetration depth of the acoustic pulses when operating in the second mode and improves the imaging resolution when the processing module operates in the first mode, thus improving the switching effect between the first mode and the second mode.

[0078] If the transducer elements 210 are divided into more than two sets of transducers, the processing module may be adapted to operate in more than two modes to, for example, increase the range of the effective elevation length of the transducer elements 210. For example, the second mode may include controlling the transducer elements such that only the first set and the second set contribute to the acoustic pulses emitted by the transducer elements, and there may be a third mode in which the processing module controls the transducer elements such that the first set, the second set, and the third set of the acoustic elements contribute to the acoustic pulses emitted by the transducer elements 210.

[0079] Preferably, in any operating mode of the processing module, all sets of acoustic elements that contribute to the acoustic pulses emitted by the transducer elements are adjacent to at least one other set of acoustic elements that contribute to the acoustic pulses emitted by the transducer elements. This ensures that the elevation length of the transducer elements can be controlled with a minimum reduction in resolution.

[0080] Although Figure 2 Only 10 transducers are illustrated, for example, 5 transducers each in a first set 215 and a second set 216 of transducers, but embodiments may include any number of transducers. The total number of transducers may be between 10 and 100, for example, between 5 and 50 transducers per set (assuming only two sets).

[0081] Preferably, each set of transducers includes at least 2 transducers, for example, at least 10 transducers, for example, between 10 and 15 transducers. This provides a good balance between penetration and resolution for different modes.

[0082] Of course, the number of transducers in each set does not need to be exactly the same. In some embodiments, the number of transducers in the second set is greater than the number of transducers in the first set to improve the switchable effect between a high-resolution (and low-penetration) operation mode and a high-penetration (but low-resolution) operation mode.

[0083] The exact number of transducers in each set of transducers may vary due to implementation details, i.e., depending on the desired imaging penetration and / or resolution in each mode.

[0084] Although in Figure 2 the first set 215 and the second set 216 are adjacent to each other laterally, various alternative exemplary embodiments may include a first set and a second set that are adjacent to each other in the longitudinal direction of a medical intervention device (e.g., an intravascular imaging probe) on which the first set and the second set of transducers are mounted. In further alternative embodiments, the corresponding transducers of the first set and the second set extend along the longitudinal dimension of the transducers.

[0085] Figure 3 Illustrated are the effects of different numbers of sets of transducers that control the transducer elements 310 of the acoustic imaging probe 300.

[0086] When the processing module operates in a first mode and only the first set of transducers contributes to the acoustic pulses emitted by the transducer element 310, the effective elevation length of the transducer element 310 is a first length d 1 .

[0087] When the processing module operates in a second mode and both the first set and the second set of transducers contribute to the acoustic pulses emitted by the transducer element 310, the effective elevation length of the transducer element 310 is a second length d 2 , which is greater than the first length.

[0088] In this way, the number of the set of transducers contributing to the acoustic pulses emitted by the transducer elements is controlled, thereby controlling the effective elevation length of the transducer elements.

[0089] Figure 4 FIG. illustrates a computer-implemented method 400 according to an embodiment of the present invention. The method may be implemented in an acoustic imaging probe (e.g., those acoustic imaging probes as previously described).

[0090] Method 400 includes a step 410 of determining in which mode the processing module will operate. This determination may be in response to a user input 490 (e.g., to allow the user to select the mode of the processing module) or some other criterion 495 (e.g., whether the processing module is operating according to a particular scenario or strategy, examples of which will be provided later).

[0091] In step 410, in response to determining that the processing module will operate in a first mode, the method moves to step 420: controlling the transducer elements (of the acoustic imaging probe) such that only a first set of one or more adjacent transducers emits acoustic pulses and the transducers of the first set operate synchronously when emitting the acoustic pulses to provide a first combined acoustic pulse.

[0092] In step 410, in response to determining that the processing module will operate in a second mode, the method moves to step 430: controlling the transducer elements such that both a first set and a second set of one or more adjacent transducers emit acoustic pulses and the transducers of the first set and the second set operate synchronously when emitting the acoustic pulses to provide a second combined acoustic pulse.

[0093] Steps 420 and 430 represent different modes of the processing module. Thus, there may be methods of operating the processing module to be capable of operating in a first mode (where step 420 is performed) or a second mode (where step 430 is performed).

[0094] After the transducer elements have provided (combined) acoustic pulses (i.e., steps 420 or 430 have been performed), the method may move to step 440: receiving echoes or reflections of the provided acoustic pulses at the transducer elements. Then, in step 450, the transducer elements generate a received signal in response to the received echoes or reflections. In step 460, the generated received signal may be used to generate an acoustic image of the region into which the acoustic pulses were emitted. The method of generating an acoustic image using the received signal in response to the echoes of the acoustic pulses will be apparent to those skilled in the art.

[0095] After the received signal is generated, the method can return to step 410, as shown, and the process for transmitting the acoustic pulse can start again. Those skilled in the art will readily appreciate that when the acoustic imaging is completed, the method can be terminated (e.g., the user terminates the acoustic imaging process or the memory is full).

[0096] Figure 5 Method 500, which is illustrated, promotes a combined strategy for a processing module in which the processing module iteratively switches between operating in a first mode and operating in a second mode.

[0097] Method 500 includes step 510 of determining whether the processing module is to be operated according to the combined strategy. This can be performed, for example, by monitoring a user input signal indicative of the desired mode and / or strategy of the processing module.

[0098] In step 510, in response to a negative determination (i.e., the processing module will not be operated according to the combined strategy), the method simply proceeds to execute method 400 (e.g., in response to a user input selection of the first mode or the second mode).

[0099] In step 510, in response to an affirmative determination, the method proceeds to step 520: determining in which mode the processing module is to operate. In particular, step 520 can include determining whether to switch modes.

[0100] In particular, step 520 can include determining whether a certain switching criterion has been met. For example, the switching criterion can include a predetermined number of combined acoustic pulses emitted when the transducer operates in the current mode, or a predetermined length of time elapsed since switching to the current mode.

[0101] In step 520, if the switching criterion is met, the method proceeds to step 530: selecting a different operating mode for the processing module. Otherwise, the method performs step 540: selecting the current operating mode for the processing module.

[0102] After the operating mode is selected, the processing module executes process 400 (wherein the selected mode is the mode in which the processing module is to operate).

[0103] For the first iteration in which step 510 determines that operation will be in the combined strategy, step 520 can include arbitrarily selecting (e.g., according to a predetermined selection strategy (e.g., selecting the first mode)) the mode in which the processing module is to operate.

[0104] Step 530 can include switching to a different mode according to some predetermined strategy or pattern. Different combined strategies can operate according to different patterns.

[0105] For example, the first combination mode can only iteratively switch between the first mode and the second mode. Different second combination modes (e.g., this combination mode may be available if the transducer elements include three sets of transducers) can switch from the first mode to the second mode to the third mode, and then repeat the pattern. Different third combination modes (e.g., this combination mode may be available if the transducer elements include three sets of transducers) can switch from the first mode to the second mode to the third mode, then switch back to the second mode, and then repeat the pattern.

[0106] The exact mode can depend on the number of sets of available transducers to, for example, control the pattern of how the magnitude of the elevation length changes over time.

[0107] The switching criteria used in step 520 may be different for different modes of the processing module and / or different iterations of method 500.

[0108] For example, the combination strategy can only iteratively switch between the first mode and the second mode, where the switching criteria for the first mode are met when a first predetermined number of acoustic pulses have been emitted (since starting to operate in the first mode), and the switching criteria for the second mode are met when a different second predetermined number of acoustic pulses have been emitted (since starting to operate in the second mode).

[0109] As another example, the combination strategy can iteratively switch according to a first predetermined pattern: a first instance of the first mode; a first instance of the second mode; a second instance of the first mode; and a second instance of the second mode. The strategy can switch from the first instance of the first mode to the first instance of the second mode in response to a first predetermined number of acoustic pulses emitted (since the processing module started operating in the first instance of the first mode). The strategy can switch from the first instance of the second mode to the second instance of the first mode in response to a (preferably different) second predetermined number of acoustic pulses emitted (since the processing module started operating in the first instance of the second mode). The strategy can switch from the second instance of the first mode to the second instance of the second mode in response to a (preferably different) third predetermined number of acoustic pulses emitted (since the processing module started operating in the second instance of the first mode). The strategy can switch back from the second instance of the second mode to the first instance of the first mode in response to a (preferably different) fourth predetermined number of acoustic pulses emitted (since the processing module started operating in the second instance of the second mode).

[0110] Other suitable examples of the combination strategy will be obvious to those skilled in the art to facilitate the processing module to switch between two or more different operating modes according to a certain predetermined pattern.

[0111] Iteratively repeat the method 500, for example until a certain termination criterion is met (e.g., the user terminates the acoustic imaging process or the memory for storing the data obtained during the acoustic imaging process is full).

[0112] Further reference Figure 4 , the selected mode (in step 430 or 440) can be used as another criterion 495 for input to method 400.

[0113] The above embodiments have been described in the context of a single transducer element. However, it will be appreciated that an acoustic imaging probe can include a plurality of transducer elements (e.g., a plurality of transducer elements arranged in an array of transducer elements).

[0114] Thus, an acoustic imaging probe can include a plurality of transducer elements, each transducer element including a first set and a second set of transducers, wherein a processing module is configured to control the operation of each of the plurality of transducer elements, wherein: when operating in a first mode, the processing module controls each transducer element such that only one or more adjacent transducers of the first set of each transducer element emit acoustic pulses and the transducers of the first set of each transducer element operate synchronously when emitting the acoustic pulses to provide a first combined acoustic pulse; and when operating in a second mode, the processing module controls each transducer element such that both the first set and the second set of one or more adjacent transducers of each transducer element emit acoustic pulses and the transducers of the first set and the second set of each transducer element operate synchronously when emitting the acoustic pulses to provide a second combined acoustic pulse.

[0115] The plurality of transducer elements can be controlled in a phased array manner such that each transducer element emits a combined acoustic pulse according to a predetermined pattern. Other methods of controlling the plurality of transducer elements (e.g., in a synchronous or linear manner) will be apparent to those skilled in the art.

[0116] Embodiments of the present invention are particularly advantageous when the transducer element (or if there are multiple transducer elements, each transducer element) is a linear transducer element and / or the acoustic imaging probe is configured for intravascular ultrasound (IVUS).

[0117] In the case of referring to user input, an acoustic ultrasound probe can include a user interface for receiving user input (to, for example, indicate a desired mode and / or strategy).

[0118] Reference Figure 6 , the general operation of an exemplary ultrasound system will now be described. The ultrasound system is an example of an acoustic imaging system, and those skilled in the art will be able to modify the described ultrasound imaging system to perform non-ultrasound acoustic imaging if desired.

[0119] The system includes an array transducer probe 4 having an array of transducers 8 or transducer elements 6 for transmitting ultrasonic waves and receiving echo information. The transducer elements 6 may include: CMUT transducers; piezoelectric transducers formed of materials such as PZT or PVDF; or any other suitable transducer technology. In this example, the array of transducer elements 6 is a two-dimensional array of transducers 8 capable of scanning a two-dimensional plane or three-dimensional volume of an area of interest. In another example, the array of transducer elements may be a 1D array (i.e., a linear array).

[0120] The transducer elements 6 making up the array of transducers 8 are coupled to a microwave beamformer 12 that controls signal reception by the transducer elements. The microwave beamformer is capable of performing at least partial beamforming on signals received by sub-arrays (commonly referred to as "groups" or "tiles") of transducers, as described in U.S. Patents US 5997479 (Savord et al.), US 6013032 (Savord), and US 6623432 (Powers et al.).

[0121] It should be noted that the microwave beamformer is entirely optional. Additionally, the system includes a transmit / receive (T / R) switch 16 that can be coupled to the microwave beamformer 12 and switch the array between a transmit mode and a receive mode, and protect the main beamformer 20 from high-energy transmit signals in the case where no microwave beamformer is used and the main system beamformer directly operates the array of transducer elements. The transmission of ultrasonic waves from the transducer elements 6 is directed by a transducer controller 18 (an embodiment of the processing module described herein), which is coupled to the microwave beamformer through the T / R switch 16 and is coupled to a main transmit beamformer (not shown) that can receive input from user operations from a user interface or control panel 38. The controller 18 can include a transmit circuit arranged to drive the transducers 8 of the array 6 during the transmit mode (either directly or via the microwave beamformer).

[0122] In a typical line-by-line imaging sequence, the beamforming system within the probe can operate as follows. During transmission, the beamformer (depending on the implementation, which can be a microwave beamformer or the main system beamformer) activates the array of transducer elements or a sub-aperture of the array of transducer elements (e.g., for the present disclosure, depending on the mode of the transducer controller). The sub-aperture can be a one-dimensional row of transducers or a two-dimensional tile within a larger array. In the transmit mode, the focusing and steering of the ultrasonic beam generated by the array or sub-aperture of the array are controlled as described below.

[0123] When an echo signal backscattered from an object is received, the received signal is subjected to receive beamforming (described below) to align the received signal, and in the case of using sub-apertures, the sub-apertures are then shifted, for example, by a transducer. Then the shifted sub-apertures are activated and the process is repeated until all transducer elements of the transducer element array are activated.

[0124] For each line (or each sub-aperture), the total received signal of the associated line used to form the final ultrasound image will be the sum of the voltage signals measured by the transducers of a given sub-aperture during the reception period. After the beamforming process described below, the resulting line signal is typically referred to as radio frequency (RF) data. Then, each line signal (RF data set) generated by the individual sub-apertures is subjected to additional processing to generate the lines of the final ultrasound image. The variation of the amplitude of the line signal over time will contribute to the variation of the brightness of the ultrasound image with depth, where high amplitude peaks will correspond to bright pixels (or sets of pixels) in the final image. Peaks occurring near the start of the line signal will represent echoes from shallow structures, while peaks gradually occurring later in the line signal will represent echoes from structures at increasing depths within the object.

[0125] One of the functions controlled by the transducer controller 18 is the direction of beam steering and focusing. The beam can be steered straight ahead (orthogonal to) the transducer element array, or steered at different angles to obtain a wider field of view. The steering and focusing of the transmit beam can be controlled according to the transducer actuation time.

[0126] Two methods can be distinguished in general ultrasound data acquisition: plane wave imaging and "beam steering" imaging. The difference between these two methods lies in the presence of beamforming in the transmit mode ("beam steering" imaging) and / or the receive mode (plane wave imaging and "beam steering" imaging).

[0127] First looking at the focusing function, by activating all transducers simultaneously, the transducer element array generates a plane wave that diverges as it travels through the object. In this case, the beam of the ultrasonic wave remains unfocused. By introducing a position-dependent time delay into the activation of the transducers, it is possible to make the wavefront of the beam converge at a desired point, which is called the focus zone. The focus zone is defined as the point where the lateral beam width is less than half of the transmit beam width. In this way, the lateral resolution of the final ultrasound image is improved.

[0128] For example, if the time delay causes the transducer to be serially activated starting from the outermost element and ending at the (one or more) central elements of the transducer element array, a focal zone will be formed at a given distance from the probe, which is in line with the (one or more) central elements. The distance of the focal zone from the probe will vary according to the time delay between each subsequent round of transducer activation. After the beam passes through the focal zone, it will start to diverge, thus forming a far-field imaging region. It should be noted that for a focal zone located close to the transducer element array, the ultrasonic beam will diverge rapidly in the far field, resulting in beam width artifacts in the final image. Generally, due to a large amount of overlap in the ultrasonic beam, the near field located between the transducer element array and the focal zone shows little detail. Therefore, changing the position of the focal zone can cause a significant change in the quality of the final image.

[0129] It should be noted that in the transmit mode, unless the ultrasonic image is divided into multiple focal zones (each of the multiple focal zones may have a different transmit focus), only one focus can be defined.

[0130] In addition, when receiving an echo signal from within an object, the inverse process of the above process can be performed in order to perform receive focusing. In other words, the incoming signal can be received by the transducer and subjected to an electronic time delay before being passed into the system for signal processing. The simplest example of this situation is called delay and sum beamforming. The receive focusing of the transducer element array can be dynamically adjusted according to time.

[0131] Now looking at the function of beam steering, by correctly applying a time delay to the transducer, a desired angle can be imparted to the ultrasonic beam when the ultrasonic beam leaves the transducer element array. For example, by activating the transducers on the first side of the transducer element array and then ending the activation of the remaining transducers in sequence on the opposite side of the array, the wavefront of the beam will be angled towards the second side. The magnitude of the steering angle relative to the normal of the transducer element array depends on the magnitude of the time delay between subsequent transducer activations.

[0132] In addition, the steered beam can be focused, where the total time delay applied to each transducer element is the sum of both the focusing time delay and the steering time delay. In this case, the transducer element array is called a phased array.

[0133] In the case of CMUT transducers that require a DC bias voltage for their activation, the transducer controller 18 can be coupled to control the DC bias control 45 for the transducer element array. The DC bias control 45 sets the (one or more) DC bias voltages applied to the CMUT transducers.

[0134] For each transducer element of the transducer element array, an analog ultrasound signal, often referred to as channel data, enters the system through a receive channel. In the receive channel, the microwave beamformer 12 generates a partially beamformed signal based on the channel data, which is then passed to the main receive beamformer 20, where the partially beamformed signals from the individual patches of the transducer are combined into a fully beamformed signal (which is referred to as radio frequency (RF) data). The beamforming performed at each stage can be carried out as described above, or can include additional functions. For example, the main beamformer 20 can have 128 channels, each of which receives partially beamformed signals from dozens or hundreds of transducer patches. In this way, the signals received by thousands of transducers of the transducer element array can effectively contribute to a single beamformed signal.

[0135] The beamformed received signal is coupled to the signal processor 22. The signal processor 22 can process the received echo signals in various ways, such as bandpass filtering; decimation; I and Q component separation; and harmonic signal separation, which is used to separate linear signals from nonlinear signals, so as to be able to identify the nonlinear (higher harmonics of the fundamental frequency) echo signals returning from tissues and microbubbles. The signal processor can also perform additional signal enhancement, such as speckle reduction, signal compounding, and noise cancellation. The bandpass filter in the signal processor can be a tracking filter, and when receiving echo signals from increasing depths, the passband of the tracking filter slides from a higher frequency band to a lower frequency band, thereby suppressing the higher frequency noise from greater depths (which usually has no anatomical information).

[0136] The beamformer for transmission and the beamformer for reception are implemented with different hardware and can have different functions. Of course, the design of the receiver beamformer takes into account the characteristics of the transmitter beamformer. For simplicity, only the receiver beamformers 12, 20 are shown in Figure 6 There will also be a transmit chain in the entire system, which includes a transmit microwave beamformer and a main transmit beamformer.

[0137] The function of the microwave beamformer 12 is to provide an initial combination of signals in order to reduce the number of analog signal paths. This is usually performed in the analog domain.

[0138] The final beamforming is completed in the main beamformer 20 and is usually done after digitization.

[0139] The transmit channel and the receive channel use the same transducer element 6 with a fixed frequency band. However, the bandwidth occupied by the transmit pulse can vary according to the transmit beamforming used. The receive channel can capture the entire transducer bandwidth (which is the classical method), or by using bandpass processing so that it can only extract the bandwidth containing the desired information (e.g., the harmonics of the main harmonic).

[0140] Then, the RF signal can be coupled to a B-mode (i.e., brightness mode or 2D imaging mode) processor 26 and a Doppler processor 28. The B-mode processor 26 performs amplitude detection on the received ultrasonic signal to image structures in the body (e.g., organ tissues and blood vessels). In the case of line-by-line imaging, each line (beam) is represented by an associated RF signal, and its amplitude is used to generate the brightness value to be assigned to the pixel in the B-mode image. The exact position of the pixel within the image is determined by the position along which the amplitude of the associated RF signal is measured and the number of lines (beams) of the RF signal. As described in U.S. Patent US6283919 (Roundhill et al.) and U.S. Patent US 6458083 (Jago et al.), the B-mode image of such a structure can be formed in a harmonic image mode or a fundamental image mode or a combination of both. The Doppler processor 28 processes signals that are different in time due to tissue movement and blood flow for detecting moving substances (e.g., the blood cell flow in the image field). The Doppler processor 28 typically includes a wall filter, the parameters of which are set such that echoes returned from selected types of materials in the body are passed or rejected.

[0141] The structural and motion signals generated by the B-mode processor and the Doppler processor are coupled to the scan converter 32 and the multi-planar reformatting unit 44. The scan converter 32 arranges the echo signals in the spatial relationship at which the echo signals are received in a desired image format. In other words, the scan converter is used to convert the RF data from the cylindrical coordinate system to the Cartesian coordinate system suitable for displaying the ultrasonic image on the image display 40. In the case of B-mode imaging, the brightness of the pixel at a given coordinate is proportional to the amplitude of the RF signal received from that position. For example, the scan converter can arrange the echo signals into a two-dimensional (2D) sector format or a three-dimensional (3D) image in the shape of a pyramid. The scan converter is capable of overlaying colors corresponding to the motion at each point in the image field on the B-mode structural image, where the Doppler estimated velocity at these points produces a given color. The combined B-mode structural image and the color Doppler image depict the tissue motion and blood flow within the structural image field. As described in U.S. Patent No. US 6443896 (Detmer), the multi-planar reformatting unit converts the echoes received from points in a common plane in a volume region of the body into an ultrasonic image of that plane. As described in U.S. Patent No. US46530885 (Entrekin et al.), the volume renderer 42 converts the echo signals of the 3D data set into a 3D image of a projection as viewed from a given reference point.

[0142] The 2D image or 3D image is coupled from the scan converter 32, the multi-planar reformatting unit 44, and the volume renderer 42 to the image processor 30 for further enhancement, buffering, and temporary storage for display on the image display 40. The imaging processor may be adapted to remove some imaging artifacts from the final ultrasonic image, such as: acoustic shadows caused by strong attenuators or refraction; post-enhancement caused by, for example, weak attenuators; reverberation artifacts at positions adjacent to highly reflective tissue interfaces, etc. In addition, the image processor may be adapted to process certain speckle reduction functions to improve the contrast of the final ultrasonic image.

[0143] In addition to being used for imaging, the blood flow values generated by the Doppler processor 28 and the tissue structure information generated by the B-mode processor 26 are also coupled to the quantization processor 34. In addition to the structural measurement results (e.g., organ size and gestational age), the quantization processor also produces metrics for different flow conditions (e.g., the volume rate of blood flow). The quantization processor can receive inputs from the user control panel 38 (e.g., the points in the anatomical structure of the image to be measured).

[0144] The output data from the quantization processor is coupled to the graphics processor 36 for reproducing an image together with measurement graphics and measurement values on the display 40 and for outputting an audio signal from the display device 40. The graphics processor 36 is also capable of generating graphic overlays for display with the ultrasound image. These graphic overlays can include criterion identification information (e.g., patient name), date and time of the image, imaging parameters, etc. To this end, the graphics processor receives an input (e.g., patient name) from the user interface 38. The user interface is also coupled to the transmit controller 18 to control the generation of ultrasound signals occurring from the array transducer elements 6 and thus to control the images produced by the transducer element array and the ultrasound system. The transmit control function of the controller 18 is only one of the functions performed. The controller 18 also takes into account the operating mode (given by the user) and the corresponding required transmitter configuration and bandpass configuration in the receiver analog-to-digital converter. The controller 18 can be a state machine with fixed states.

[0145] The user interface is also coupled to the multi-planar reformatting unit 44 for selecting and controlling the planes of a plurality of multi-planar reformatting (MPR) images, which planes can be used to perform quantization measurements in the image field of the MPR images.

[0146] A person skilled in the art will be able to easily develop a processing system for performing any of the methods described herein. Accordingly, each step of the flowchart can represent a different action performed by the processing system and can be performed by a corresponding module of the processing system. The processing system can be or form part of the processing module of the imaging probe.

[0147] Accordingly, embodiments can utilize a processing system. The processing system can be implemented in a variety of ways using software and / or hardware to perform the various functions required. A processor is an example of a processing system using one or more microprocessors, which one or more microprocessors can be programmed using software (e.g., microcode) to perform the required functions. However, the processing system can be implemented with or without a processor and can also be implemented as a combination of dedicated hardware performing some functions and a processor (e.g., one or more programmed microprocessors and associated circuitry) performing other functions.

[0148] Examples of processing system components that can be used in various embodiments of the present disclosure include, but are not limited to, conventional microprocessors, application specific integrated circuits (ASICs), and field programmable gate arrays (FPGAs).

[0149] In various embodiments, a processor or processing system may be associated with one or more storage media, e.g., volatile and non-volatile computer memories such as RAM, PROM, EPROM, and EEPROM. One or more programs may be encoded on the storage media, and when the one or more programs are run on one or more processors and / or processing systems, they perform the required functions. The various storage media may be fixed within the processor or processing system or may be transferable, such that the one or more programs stored thereon can be loaded into the processor or processing system.

[0150] It should be understood that the disclosed methods are preferably computer-implemented methods. Accordingly, the concept of a computer program including code units is also proposed, where the code units are for implementing any of the described methods when the program is run on a processing system (e.g., a computer). Thus, different code portions, lines, or blocks of a computer program according to an embodiment may be run by a processing system or computer to perform any of the methods described herein. In some alternative embodiments, the functions indicated in one or more block diagrams or one or more flowcharts may not occur in the order indicated in the figures. For example, two successive blocks shown may actually be run substantially simultaneously, or the blocks may sometimes be run in the reverse order, depending on the functions involved.

[0151] Those skilled in the art will be able to understand and realize variations of the disclosed embodiments when studying the drawings, the disclosure, and the claims, in practicing the claimed invention. In the claims, the word "comprising" does not exclude other elements or steps, and the words "a" or "an" do not exclude a plurality. A single processor or other unit may implement the functions of several items recited in the claims. Although certain measures are recited in mutually different dependent claims, this does not indicate that a combination of these measures cannot be used advantageously. If a computer program is discussed above, it may be stored / distributed on a suitable medium, e.g., an optical storage medium or a solid-state medium supplied together with or as part of other hardware, but it may also be distributed in other forms, e.g., via the Internet or other wired or wireless telecommunication systems. If the term "adapted to" is used in the claims or the specification, it should be noted that the term "adapted to" is intended to be equivalent to the term "configured to". Any reference signs in the claims should not be construed as limiting the scope.

Claims

1. An acoustic imaging probe (100, 200, 300), comprising: Transducer elements (110, 210, 310), which include: A first set (215) of adjacent transducers (211); and A second set (216) of adjacent transducers, wherein the first set is adjacent to the second set; Wherein each transducer is configured to controllably emit an acoustic pulse and receive one or more echo signals in response to the emitted acoustic pulse, A processing module (120, 220, 320), which is configured to control the operation of the transducer elements at least in the following modes: A first mode, wherein the processing module is configured to control the transducer elements such that only the first set of transducers emits an acoustic pulse and the transducers in the first set operate synchronously when emitting the acoustic pulse to provide a first combined acoustic pulse; and A second mode, wherein the processing module is configured to control the transducer elements such that both the first set and the second set of transducers emit acoustic pulses and the transducers in the first set and the second set operate synchronously when emitting the acoustic pulse to provide a second combined acoustic pulse; Wherein the processing module (120, 220, 320) is further configured to be operable according to a combination scheme in which the processing module iteratively switches between operating in the first mode and operating in the second mode.

2. The acoustic imaging probe (100, 200, 300) according to claim 1, wherein, Each transducer (211) is configured to require a voltage bias to controllably emit an acoustic pulse, and The processing module (120, 220, 320) is configured to: When operating in the first mode, provide a voltage bias only to the first set of transducers; and When operating in the second mode, provide a voltage bias to both the first set and the second set of transducers.

3. The acoustic imaging probe according to claim 1 or 2, wherein, The processing module (120, 220, 320) is configured to control the transducer elements such that the center frequency of the first combined acoustic pulse is different from the center frequency of the second combined acoustic pulse.

4. The acoustic imaging probe (100, 200, 300) according to claim 3, wherein, The processing module (120, 220, 320) is configured to control the transducer elements such that the center frequency of the first combined acoustic pulse is greater than the center frequency of the second combined acoustic pulse.

5. The acoustic imaging probe according to claim 1, wherein, When operating according to the combination scheme, the processing module switches between the first mode and the second mode in response to a predetermined number of combined acoustic pulses emitted by the transducers.

6. The acoustic imaging probe according to claim 1, 2, or 5, wherein: The transducer elements further include a third set of adjacent transducers, and the third set of transducers is adjacent to the second set of transducers; The processing module is also operative in a third mode, in which the processing module is configured to control the transducer elements such that the first, second, and third sets of the transducer emit acoustic pulses and the transducers of the first, second, and third sets operate synchronously when emitting the acoustic pulses to provide a third combined acoustic pulse.

7. The acoustic imaging probe according to claim 1, 2, or 5, wherein, the processing module is adapted to monitor the first and second sets of transducers to generate received signals in response to one or more echo signals received by the first and second sets of transducers.

8. The acoustic imaging probe according to claim 1, 2, or 5, wherein, the transducer element comprises a capacitive micromachined ultrasonic transducer.

9. The acoustic imaging probe according to claim 1, 2, or 5, wherein, the transducer element comprises a piezoelectric transducer.

10. The acoustic imaging probe according to claim 1, 2, or 5, wherein, the processing module is configured to respond to a user input signal to select an operating mode of the transducer element.

11. The acoustic imaging probe according to claim 1, 2, or 5, comprising a plurality of transducer elements, each transducer element comprising a first and a second set of transducers.

12. A computer-implemented method (400) of controlling an acoustic imaging probe (100, 200, 300) comprising transducer elements (110, 210, 310), the transducer elements comprising: a first set (215) of adjacent transducers (211); and a second set (216) of adjacent transducers, the first set being adjacent to the second set, wherein each transducer is configured to controllably emit an acoustic pulse and receive one or more echo signals in response to the emitted acoustic pulse, the computer-implemented method comprising: using at least two modes to control the transducer elements, the two modes comprising: a first mode (420), in which only the first set of transducers emits acoustic pulses and the transducers of the first set operate synchronously when emitting the acoustic pulses to provide a first combined acoustic pulse; and a second mode (430), in which both the first and second sets of adjacent transducers emit acoustic pulses and the transducers of the first and second sets operate synchronously when emitting the acoustic pulses to provide a second combined acoustic pulse; wherein the method comprises operating according to a combination scheme that iteratively switches between operating in the first mode and operating in the second mode.

13. A computer program product comprising computer program code units which, when run on a computing device having a processing system, cause the processing system to perform all the steps of the method according to claim 12.

14. A processing module configured to perform the method according to claim 12.

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