System for optimizing imaging aperture

Abstract

The present invention relates to methods, systems, and devices that provide imaging arrays having a row and column addressing configuration and that can be controlled via bias activation, thereby enabling selection and optimization of imaging apertures for ultrafast imaging. For example, the present invention provides imaging array designs that use row (or column) activation in combination with bias adjustment of the row and column array structure, enabling high quality, flexible ultrasound imaging, particularly for cylindrical array applications.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims priority to and the benefit of U.S. Provisional Application No. 63 / 437,428, filed January 6, 2023, the contents of which are incorporated herein by reference in their entirety.

[0002] The present invention relates generally to ultrasound imaging, and more particularly to systems and devices that provide imaging arrays having a matrix addressing configuration and that can be controlled via bias activation, thereby enabling selection and optimization of imaging apertures for ultrafast imaging. [Background technology]

[0003] Ultrasound imaging is a medical imaging technique for imaging organs and soft tissues within the human body. Ultrasound images are created based on the reflection of high-frequency sound waves from body structures. The strength (amplitude) of the sound signal, along with the time it takes for the waves to travel through the body, provides the information needed to create the image.

[0004] For example, catheter-based intravascular ultrasound imaging techniques employed within the vasculature (e.g., intravascular ultrasound (IVUS) or intracardiac echocardiography (ICE)) are typically performed using two-dimensional (2D) ultrasound imaging. In an IVUS / ICE imaging system, an ultrasound transducer assembly is attached to the distal end of a catheter. The catheter is carefully maneuvered through the patient's body to an area of ​​interest, such as within the coronary arteries (for IVUS) or the right atrium (for ICE). The transducer assembly transmits ultrasound waves and receives echoes from those waves. The received echoes are then converted into electrical signals and transmitted to processing equipment, where the resulting ultrasound image of the area of ​​interest can be displayed.

[0005] Conventional 2D ultrasound imaging is widely used because it can dynamically display 2D images of a region of interest in real time. 2D intravascular ultrasound is a standard procedure, but it requires the operator to understand the immediate anatomy for navigation. This requires a high degree of dexterity in steering the catheter image plane and visualizing the target structure for certain interventional use cases. Therefore, both the catheter and the imaging plane must be steered in parallel. 2D imaging is also limited to displaying only slices of the anatomy.

[0006] Furthermore, in typical ultrasound systems configured to visualize internal body regions, dynamic forces are often employed, resulting in dynamic movement of the body region over time. These dynamic forces and movements make it difficult to stabilize the internal imaging device and generate consistent and accurate images unless imaging of the structure can be enabled in real time (e.g., >20 Hz). As a result, the captured images often lack the necessary quality required to prescribe appropriate treatment or therapy. Due to the dynamic forces and movements at play, internal real-time imaging is limited to small two-dimensional areas or, as described below, three-dimensional volumetric regions, respectively.

[0007] 2D array transducers enable three-dimensional (3D) ultrasound imaging. 3D ultrasound imaging was developed to address the shortcomings of 2D ultrasound imaging and help diagnosticians and interventionalists gain a thorough understanding of spatial anatomical relationships. In particular, physicians can view any plane of the reconstructed 3D volume as well as a panoramic view of the region of interest. Therefore, 3D imaging can provide excellent depiction and evaluation of target structures, such as volumetric assessment.

[0008] However, 3D imaging systems have drawbacks and limitations. For example, 3D imaging systems provide a view of a region of interest that is limited to a pyramidal volume (e.g., a trapezoidal fan angle facing either side or forward from the catheter), which is further limited to a 90-degree by 60-degree sector aperture for advanced imaging catheters. Thus, while 2D array transducers have enabled 3D ultrasound imaging, a difficult engineering tradeoff still exists between system complexity and achievable image quality. Thus, while 3D ultrasound imaging offers significant promise for a wide range of clinical applications, its clinical impact is currently limited, in part, because image quality is often inferior to 2D imaging using linear or phased array transducers. Imaging the entire circumference of a catheter in a 360-degree field of view overcomes the limitations of 2D and 3D limited fields of view described above and, therefore, can enable clinical users to deliver better therapy. Summary of the Invention [Means for solving the problem]

[0009] The present invention recognizes the shortcomings of current 3D ultrasound systems, namely, the technical challenges that limit the implementation of a full 360-degree view ultrasound catheter probe for 3D imaging without compromising image quality. In particular, a major challenge in current systems is the connection between the imaging electronics, such as an application-specific integrated circuit (ASIC), and the flexible ultrasound transducer matrix array, which leads to wiring congestion in fully wired, high-density 2D arrays as the channel count increases. In contrast to rigid arrays (in which the array can be integrated directly with the underlying imaging or processing ASIC), flexible arrays do not geometrically allow integration into the rigid ASIC directly below, and therefore signal interconnection is more challenging for such designs.

[0010] For example, to achieve a flexible imaging array capable of full-circumference imaging, sampling requires a high element count both laterally (along the cylindrical length of the array), with the center-to-center distance (pitch) of two adjacent elements being less than half a wavelength, and also in the elevation direction (around the cylindrical circumference of the array), with angular spacing determined by wave propagation. These requirements result in tens of thousands of elements, leaving limited space for electronics, making individual connections to each element impossible. The required number of channel connections quickly becomes impractical for large arrays or invasive probes, where cable and probe size must be small. Furthermore, wired transmission of all data is impossible without combining multiple signals (digital or analog) into a single composite signal (multiplexing). In addition, wireless transmission of raw data, for example from an ASIC in a catheter tip, would require tens of gigabytes per second if all elements receive in parallel. Wireless data transmission is also impossible because the data rate requirements are enormous.

[0011] The present invention addresses these shortcomings by providing systems, devices, and methods that provide high-quality, full 360-degree, ultrafast imaging using a novel imaging array architecture that avoids array subsampling and extensive processing in hardware. Specifically, the devices of the present invention include imaging arrays and system architectures that achieve ultrafast imaging within in-plane and out-of-plane apertures, specifically optimizing the imaging aperture based on a matrix addressing scheme in combination with bias voltage adjustment, providing high-performance, flexible, and fully software-defined imaging. Thus, the systems, methods, and devices of the present invention provide flexible imaging arrays that are capable of transmitting and receiving ultrafast ultrasound signals to achieve full 360-degree view imaging without compromising image quality.

[0012] In certain embodiments, the present invention provides systems and devices for optimizing the imaging aperture and providing high-resolution, ultrafast imaging. For example, the present invention provides imaging array designs that use row (or column) activation in combination with bias adjustment of the matrix array structure, enabling high-quality, flexible ultrasound imaging, particularly for cylindrical array applications.

[0013] In particular, the systems, devices, and methods of the present invention use a novel system architecture for matrix addressing combined with bias voltage adjustment, i.e., activation. Using matrix addressing to address each individual imaging element of an imaging array limits the number of interconnects by enabling addressing of each element as a combination of row (address) and column (address). Furthermore, rows and / or columns of the imaging array can be fully activated or deactivated using bias activation for ultrasound transducer arrays, such as bias-sensitive capacitive micromechanical ultrasonic transducers (CMUTs). For example, a nominal bias voltage can be applied to a row of imaging elements to tune the imaging array to a target center frequency. Thus, imaging will be activated on that row. Similarly, a deactivation bias (e.g., applying 0V or a voltage level at which the element is minimally sensitive) deactivates the imaging row. This allows for fully enabling or disabling specific rows and / or columns according to flexible transmission / reception schemes.

[0014] Using the principles described above, matrix addressing of imaging elements within an array, combined with bias activation, achieves the desired angular aperture for ultrafast imaging. Specifically, sequential application of varying transmit / receive / bias patterns during imaging enables targeted ultrafast imaging. Thus, the present invention provides angular aperture definition and optimization for ultrafast imaging that is not limited to a 90 x 60 degree sector aperture for pyramidal volumetric views. As provided by the present invention, image aperture optimization applies to any convex array surface with a specific radius. For example, the concept may be applied to a convex surface around the entire circumference of the imaging probe, i.e., the special case of a cylindrical surface. Thus, in some embodiments, angular imaging aperture may be understood to mean an angular direction along the curvature.

[0015] Aspects of the invention include a system for optimizing an imaging aperture, the system comprising a controller operatively associated with an imaging device. In particular, the imaging device includes a transducer having an array of individual imaging elements arranged as multiple rows longitudinally along the transducer and multiple columns laterally along the cylindrical transducer, such that signal connectivity of the individual imaging elements is defined by row and column address locations of the array. The imaging device further includes a plurality of first electrodes, each connecting with a row of individual imaging elements, and a plurality of second electrodes, each connecting with a column of individual imaging elements, the second electrodes being arranged at a non-zero angle relative to the plurality of first electrodes.

[0016] The controller is coupled to a non-transitory computer-readable memory including instructions executable by the processor to cause the controller to selectively apply bias voltage levels to one or more of the plurality of first electrodes and / or the plurality of second electrodes, such that the bias voltage levels define voltages for rows or columns connected to the electrodes, activate or deactivate imaging by individual imaging elements within the row or column, and define an angular imaging aperture.

[0017] In some embodiments of the system, the angular imaging aperture is defined by the number of rows (Nr) and / or columns (Nc) to which a bias voltage is applied, and the number of interconnections between imaging elements is Nr+Nc.

[0018] In some embodiments, the system further includes multiple interface modules, each operably connected to both the controller and one electrode connecting to a row or column. Furthermore, bias voltage levels for each row and / or column are individually enabled, disabled, and set using the interface module for the row or column. In particular, to activate a desired row of imaging elements, the controller selects a transmission address corresponding to the desired row and sends a signal with a desired bias voltage level to the interface for the desired row. Furthermore, in some embodiments, to activate a desired column of imaging elements, the controller selects a transmission address corresponding to the desired column and sends a signal with a desired voltage level for the desired column to the interface. In other embodiments, the interface further includes one or more ORing diodes in series with the digital-to-analog converter (DAC) output to protect each imaging element from simultaneous activation of bias voltages at its row address location and column address location. In some embodiments, the ORing circuitry utilizes diodes and / or transistors.

[0019] In some embodiments, the controller is configured to activate single or multiple rows at a time using the same or different bias voltage levels to achieve the intended angular imaging aperture. Additionally and / or alternatively, the controller is configured to activate single or multiple columns at a time using the same or different bias voltage levels to achieve the intended angular imaging aperture.

[0020] Additionally, in some embodiments of the systems of the present invention, the controller includes a computer program with algorithms for evaluating, calculating, and optimizing the angular imaging aperture. Thus, algorithms may be used such that the controller is configured to activate single or multiple rows at a time, using the same or different bias voltage levels, to achieve an optimized angular imaging aperture. Similarly, the controller is configured to activate single or multiple columns at a time, using the same or different bias voltage levels, to achieve an optimized angular imaging aperture. In some embodiments, the controller may also be capable of controlling transmit and receive wave patterns for flexible imaging, or these capabilities may be otherwise integrated.

[0021] In some embodiments, the controller simultaneously activates multiple individual imaging elements based on the row and column address locations of the individual imaging elements. Furthermore, simultaneously activated individual imaging elements have the same or different bias voltage levels, according to embodiments of the present system. In some embodiments, bias voltages selectively applied to one or more of the multiple first electrodes and / or multiple second electrodes enable or disable transmit and / or receive functions and define transmit / receive events, each of which comprises an activation and / or adjustment scheme. Furthermore, in embodiments, the controller is configured to individually control the activation and / or adjustment scheme for each transmit / receive event, such that multiple transmit / receive events can have the same or alternating activation and / or adjustment schemes.

[0022] Also, according to some embodiments of the system, the controller includes protection circuitry operatively connected in series with each row and column of individual imaging elements so that multiple bias voltage levels cannot be applied to a given electrode simultaneously, hi other embodiments, the controller also includes an integrated circuit housed in an enclosure with the imaging elements or located on a substrate with the imaging elements.

[0023] In certain implementations of the system, the controller is housed separately from the imaging element and operably coupled to the imaging element via circuitry, which in some embodiments of the system includes at least one of one or more cable assemblies, one or more printed circuits, and / or one or more flexible printed circuits.

[0024] Furthermore, in some embodiments of the system, the controller includes an integrated circuit for bias voltage generation and control, the integrated circuit being housed in an enclosure with the imaging element or located on a substrate with the imaging element, and an analog front-end circuit housed separately from the imaging element, the analog front-end circuit comprising one or more signal generators and / or one or more signal transmitters and one or more switching circuits. In examples, the integrated circuit is housed with the analog front-end circuit in the catheter tip adjacent to the imaging element. In other embodiments, the integrated circuit is housed with the analog front-end circuit operably coupled to and located directly adjacent to the imaging element. Furthermore, in various representations of the system, the switching circuit, signal transmitter, and switching circuit are housed in a remote enclosure connected to the imaging element via circuitry comprising one or more cable assemblies, one or more printed circuits, and / or one or more flexible printed circuits.

[0025] Notably, in some embodiments of the system, the bias voltage level is adjustable to adjust the frequency of the imaging element. In some embodiments, the bias voltage levels selectively applied to the plurality of first electrodes and the plurality of second electrodes may be the same or different for each electrode, allowing the imaging frequency of the imaging element to be adjusted higher and / or lower to achieve a desired frequency. In other embodiments of the system, positive and / or negative bias voltage levels selectively applied to the plurality of first electrodes and / or the plurality of second electrodes adjust the imaging mode of operation.

[0026] In a particular expression of the present system, applying a bias voltage of 0 V or a voltage level to which the imaging elements are minimally sensitive deactivates imaging in a row or column. For example, in some embodiments, one or more columns and / or one or more rows are deactivated.

[0027] In some embodiments, the angular imaging aperture is one or more rows or columns defined based on the beam aperture sensitivity of the individual imaging elements of the array. Further, the angular imaging aperture is defined in certain embodiments as 1 row or 1 column to about 10 rows or columns.

[0028] Furthermore, in some embodiments of the system, the transducer array is a microelectromechanical systems (MEMS)-based capacitive micromachined ultrasonic transducer (CMUT), which in certain embodiments of the system is configured as a two-dimensional (2D) array structure. Further, in some embodiments, the 2D array structure is a flexible structure. The transducer may also include an electrostrictive material, which in some embodiments of the system is configured as a two-dimensional (2D) array structure.

[0029] In certain embodiments of the system, the imaging elements are acoustic sensors selectively activated by a controller based on row and / or column addresses of the acoustic sensors to receive a plurality of incident acoustic wave signals as wave data. For example, the wave data, in certain embodiments of the system, comprises at least one of plane wave data and / or diverging wave data associated with one or more plane wave transmit / receive cycles performed by the imaging elements. Furthermore, the wave data may be full-circumference three-dimensional (3D) image data.

[0030] In some embodiments, the transducer is cylindrically shaped. This provides a system embodiment in which an array of individual imaging elements is arranged in rows longitudinally along the transducer and in columns circumferentially around the transducer. Thus, in some embodiments of the system, the array comprises a number of rows (Nr), a number of individual imaging elements per row (Ne), a row spacing, and a number of columns (Nc), where the total number of imaging elements in the array is (Ne·Nr), and the individual imaging elements are connected through a number of connections, represented by Nr+Nc. For example, in some embodiments, the row spacing is between about 0.1 degrees and about 5 degrees in the angular direction.

[0031] In an example representation of the system of the present invention, a bias voltage is applied to a first electrode and connected to a second electrode to activate a transmit and / or receive function on each imaging element such that the individual imaging elements transmit and / or receive ultrasound signals in the form of ultrafast wave data. Advantageously, the transducer array includes a number of individual imaging elements per row (Ne) in an array design that enables ultrafast plane wave and / or diverging wave imaging, such that plane wave and / or diverging wave imaging modes include capturing plane wave reflected signal data at a rate of at least 10 kHz.

[0032] In another embodiment of the system of the present invention, the plurality of second electrodes are arranged orthogonal to the plurality of first electrodes.

[0033] In some embodiments, the one or more bias voltage selection circuits are connected to the controller using one or more multipoint communication interfaces.

[0034] In some embodiments, control of the transmit and / or receive functions uses one or more interfaces that are common to or separate from the interface used for bias voltage selection.

[0035] In a further aspect, the present invention provides a method for optimizing an imaging aperture, e.g., for high-resolution ultrafast imaging, comprising providing a controller operatively associated with an imaging device including a transducer having an array of individual imaging elements arranged as multiple rows lengthwise along the transducer and multiple columns widthwise along a cylindrical transducer, such that signal connectivity of the individual imaging elements is defined by row and column address locations of the array.

[0036] The imaging device further includes a plurality of first electrodes, each connecting with a row of individual imaging elements, and a plurality of second electrodes, each connecting with a column of individual imaging elements, arranged at a non-zero angle relative to the plurality of first electrodes.

[0037] The controller is coupled to a non-transitory computer-readable memory including instructions executable by the processor to cause the controller to selectively apply bias voltage levels to one or more of the plurality of first electrodes and / or the plurality of second electrodes. The method further includes applying bias voltage levels to one or more selected electrodes such that the bias voltage levels define voltages for rows or columns connected to the electrodes, activate or deactivate imaging by individual imaging elements in the row or column, and define an angular imaging aperture.

[0038] In some embodiments of the method, the angular imaging aperture is defined by the number of rows (Nr) and / or columns (Nc) to which a bias voltage is applied, and the number of interconnections between imaging elements is Nr+Nc.

[0039] In some embodiments, the method further includes multiple interface modules, each operably connected to both the controller and one electrode connecting to a row or column. Furthermore, bias voltage levels for each row and / or column are individually enabled, disabled, and set using the interface module for the row or column in some embodiments of the method. In particular, to activate a desired row of imaging elements, the controller selects a transmission address corresponding to the desired row and sends a signal with a desired bias voltage level to the interface for the desired row. Furthermore, in some embodiments, to activate a desired column of imaging elements, the controller selects a transmission address corresponding to the desired column and sends a signal with a desired voltage level for the desired column to the interface. In still other embodiments, the interface further includes one or more ORing diodes in series with the digital-to-analog converter (DAC) output to protect each imaging element from simultaneous activation of bias voltages at its row address location and column address location. In some embodiments, the ORing circuitry utilizes diodes and / or transistors.

[0040] Importantly, in some embodiments, the controller is configured to activate single or multiple rows at a time using the same or different bias voltage levels to achieve the intended angular imaging aperture. Additionally and / or alternatively, the controller is configured to activate single or multiple columns at a time using the same or different bias voltage levels to achieve the intended angular imaging aperture.

[0041] In some embodiments of the method, the controller further includes a computer program comprising algorithms for evaluating, calculating, and optimizing the angular imaging aperture. In certain embodiments, the controller is configured to activate single or multiple rows at a time using the same or different bias voltage levels to achieve the optimized angular imaging aperture. Additionally and / or alternatively, the controller is configured to activate single or multiple columns at a time using the same or different bias voltage levels to achieve the optimized angular imaging aperture. In some embodiments, the controller may also be capable of controlling transmit and receive wave patterns for flexible imaging, or these capabilities may be otherwise integrated.

[0042] In some embodiments, the controller simultaneously activates multiple individual imaging elements based on the row and column address locations of the individual imaging elements. Furthermore, simultaneously activated individual imaging elements have the same or different bias voltage levels, according to embodiments of the present method. In embodiments, bias voltages selectively applied to one or more of the multiple first electrodes and / or multiple second electrodes enable or disable transmit and / or receive functions and define transmit / receive events, each of which comprises an activation and / or adjustment scheme. Furthermore, in some embodiments, the controller is configured to individually control the activation and / or adjustment scheme for each transmit / receive event, such that multiple transmit / receive events can have the same or alternating activation and / or adjustment schemes.

[0043] According to some embodiments of the method, the controller includes protection circuitry operatively connected in series with each row and column of individual imaging elements so that multiple bias voltage levels cannot be applied to a given electrode simultaneously, hi other embodiments, the controller also includes an integrated circuit housed in an enclosure with the imaging elements or located on a substrate with the imaging elements.

[0044] In certain examples of the method, the controller is housed separately from the imaging element and operably coupled to the imaging element via circuitry, which in some embodiments of the method includes at least one of one or more cable assemblies, one or more printed circuits, and / or one or more flexible printed circuits.

[0045] Additionally, in some embodiments, the controller includes an integrated circuit for bias voltage generation and control, the integrated circuit being housed in an enclosure with the imaging element or located on a substrate with the imaging element, and an analog front-end circuit housed separately from the imaging element, the analog front-end circuit comprising one or more signal generators and / or one or more signal transmitters and one or more switching circuits. In examples, the integrated circuit is housed with the analog front-end circuit in the catheter tip adjacent the imaging element. In other examples, the integrated circuit is housed with the analog front-end circuit operably coupled to the imaging element and located directly adjacent the imaging element.

[0046] Further, in various expressions of the method, the switching circuitry, the signal transmitter, and the switching circuitry are housed in a remote enclosure that is connected to the imaging element via a circuit network that includes one or more cable assemblies, one or more printed circuits, and / or one or more flexible printed circuits.

[0047] Notably, in some embodiments of the method of the present invention, the bias voltage level is adjustable to adjust the frequency of the imaging element. In some embodiments, the bias voltage levels selectively applied to the plurality of first electrodes and the plurality of second electrodes may be the same or different for each electrode, allowing the imaging frequency of the imaging element to be adjusted higher and / or lower to achieve a desired frequency. In other embodiments, positive and / or negative bias voltage levels selectively applied to the plurality of first electrodes and / or the plurality of second electrodes adjust the imaging mode of operation.

[0048] In a particular expression of this method, applying a bias voltage of 0 V or a voltage level to which the imaging elements are minimally sensitive deactivates imaging in a row or column. For example, in some embodiments, one or more columns and / or one or more rows are deactivated.

[0049] In some embodiments of the method, the angular imaging aperture is one or more rows or columns defined based on the beam aperture sensitivity of the individual imaging elements of the array. Further, the angular imaging aperture is defined in certain embodiments as 1 row or 1 column to about 10 rows or columns.

[0050] In some embodiments, the transducer array is a microelectromechanical systems (MEMS)-based capacitive micromachined ultrasonic transducer (CMUT), which is configured as a two-dimensional (2D) array structure in certain embodiments of the method. Further, in examples, the 2D array structure is a flexible structure. The transducer may also include an electrostrictive material, which is configured as a two-dimensional (2D) array structure in some embodiments of the method.

[0051] In certain embodiments of the method, the plurality of imaging elements are acoustic sensors that receive a plurality of incident acoustic wave signals as wave data, selectively activated by a controller based on row and / or column addresses of the acoustic sensors. The wave data, in certain embodiments of the method, comprises at least one of plane wave data and / or diverging wave data associated with one or more plane wave transmit / receive cycles performed by the imaging elements. Furthermore, the wave data may be full-circumference three-dimensional (3D) image data.

[0052] In some embodiments of the method, the transducer is cylindrically shaped. This provides an embodiment of the method in which an array of individual imaging elements is arranged in rows longitudinally along the transducer and in columns circumferentially around the transducer. Furthermore, in some embodiments of the method, the array comprises a number of rows (Nr), a number of individual imaging elements per row (Ne), a row spacing, and a number of columns (Nc), where the total number of imaging elements in the array is (Ne·Nr), and the individual imaging elements are connected through a number of connections represented by Nr+Nc. For example, in some embodiments, the row spacing is between about 0.1 degrees and about 5 degrees in the angular direction.

[0053] In an exemplary expression of the method of the present invention, a bias voltage is applied to a first electrode and connected to a second electrode to activate a transmit and / or receive function on each imaging element such that the individual imaging elements transmit and / or receive ultrasound signals in the form of ultrafast wave data. Advantageously, in some embodiments, the transducer array includes a number of individual imaging elements per row (Ne) in an array design that enables ultrafast plane wave and / or diverging wave imaging, such that plane wave and / or diverging wave imaging modes include capturing plane wave reflected signal data at a rate of at least 10 kHz.

[0054] In another embodiment of the method of the present invention, the plurality of second electrodes are arranged orthogonal to the plurality of first electrodes.

[0055] In some embodiments, the one or more bias voltage selection circuits are connected to the controller using one or more multipoint communication interfaces.

[0056] In some embodiments, control of the transmit and / or receive functions uses one or more interfaces that are common to or separate from the interface used for bias pressure selection. [Brief explanation of the drawings]

[0057] [Figure 1] 1A and 1B are schematic diagrams of an exemplary ultrasound system for providing visualization and characterization of the vasculature within a patient that may be used in conjunction with the devices of the present invention.

[0058] [Figure 2] FIG. 2 is a perspective view of an imaging catheter to which the device of the present invention may be coupled.

[0059] [Figure 3] FIG. 3 is a schematic diagram of a prior art ASIC design for a matrix array probe.

[0060] [Figure 4] FIG. 4 illustrates a schematic diagram of the physical sensitivity of imaging elements in a radial direction around a cylindrical array catheter in some embodiments of the present invention.

[0061] [Figure 5] FIG. 5 illustrates active radial openings for radial rows around a cylindrical imaging catheter in one embodiment of the present invention.

[0062] [Figure 6] 6A and 6B illustrate a side view and a cross-sectional view of one embodiment of a cylindrical imaging array of the present invention.

[0063] [Figure 7] FIG. 7 illustrates a flexible imaging array and system architecture that provides row and column addressing, in which front electrodes address rings or columns and back electrodes address rows.

[0064] [Figure 8] FIG. 8 illustrates an embodiment of a cylindrical imaging array of the present invention.

[0065] [Figure 9] FIG. 9 illustrates classical matrix addressing.

[0066] [Figure 10] FIG. 10 illustrates an embodiment of bias row activation in a device of the present invention.

[0067] [Figure 11] FIG. 11 illustrates an embodiment of a system architecture of the present invention in which the transmit function can be activated by the bottom electrode and the receive function can be activated on the top electrode.

[0068] [Figure 12] FIG. 12 illustrates a non-limiting example of row activation in one embodiment of a flexible imaging array of the present invention.

[0069] [Figure 13] FIG. 13 illustrates a non-limiting example of column / ring activation in one embodiment of a flexible imaging array of the present invention.

[0070] [Figure 14] FIG. 14 illustrates activation of multiple rows of an embodiment of an imaging array of the present invention.

[0071] [Figure 15] FIG. 15 illustrates frequency adjustment of multiple active rows in one embodiment of an imaging array of the present invention.

[0072] [Figure 16A] FIG. 16A illustrates a schematic diagram of one embodiment of an interface for a row of elements in an array.

[0073] [Figure 16B] FIG. 16B illustrates an expanded view of the circuit diagram of FIG. 16A.

[0074] [Figure 17A] FIG. 17A illustrates a schematic diagram of one embodiment of an imaging array element interface for a particular row and a particular column, for example, row i and column j.

[0075] [Figure 17B] FIG. 17B illustrates an expanded view of the circuit diagram of FIG. 17A.

[0076] [Figure 18A] FIG. 18A illustrates an embodiment of the present invention in which each row of the imaging array is connected to an individual array element interface, and similarly for each column of the array, so that individual imaging elements can be addressed by row and column (row, column) addresses.

[0077] [Figure 18B] FIG. 18B illustrates an expanded view of the circuit diagram of FIG. 18A.

[0078] [Figure 19A] FIG. 19A illustrates an embodiment of an interface circuit with bias voltage selection, showing the interface circuit for an imaging element in row i and column j, ie, the imaging element at address (i,j).

[0079] [Figure 19B] FIG. 19B illustrates an expanded view of the circuit diagram of FIG. 19A.

[0080] [Figure 20]FIG. 20 illustrates an embodiment of an imaging device of the present invention in which the controller is in active communication with a computing system that includes algorithms for evaluating, calculating, and optimizing the angular imaging aperture.

[0081] [Figure 21] FIG. 21 is a schematic diagram of another embodiment of a system of the present invention for producing ultrasound images using ultrafast imaging techniques.

[0082] [Figure 22] FIG. 22 illustrates a cylindrical array transducer with rows of elements radially around the transducer that can be used to image the side of the transducer.

[0083] [Figure 23] FIG. 23 illustrates activation of a single element.

[0084] [Figure 24] FIG. 24 is a block diagram of an embodiment of a method of the present invention for imaging.

[0085] [Figure 25] FIG. 25 is a block diagram of one embodiment of a method of the present invention for optimizing the imaging aperture. DETAILED DESCRIPTION OF THE INVENTION

[0086] Detailed Description The present invention recognizes the shortcomings of current 3D ultrasound systems, including technical challenges that limit the implementation of a full 360-degree view ultrasound catheter probe for ultrasound imaging without compromising image quality. The present invention provides systems, devices, and methods for ultrafast ultrasound imaging using a uniquely configured imaging array transducer and system architecture. The present invention provides systems and devices for optimizing the imaging aperture for full 360-degree ultrafast imaging.

[0087] Specifically, the present invention provides bias selection and adjustment for row activation in combination with matrix addressing, enabling flexible imaging protocols, specifically ultrafast imaging modes (plane wave and diverging wave). Previous attempts to define imaging apertures using matrix addressing have primarily focused on focused wave imaging in planar array configurations (classical 2D matrix array settings). Thus, the present invention provides high-performance, high-quality, flexible, and fully software-defined imaging. The imaging devices and systems of the present invention are capable of ultrafast imaging, avoiding array subsampling and extensive processing in hardware, enabling flexible imaging protocols and approaches for ultrafast image reconstruction. The systems and devices of the present invention can provide flexible imaging arrays that optimize imaging apertures, including angular imaging apertures, and are capable of ultrafast, full 360-degree imaging.

[0088] As an overview and generally understood, ultrasound imaging (sonography) uses high-frequency sound waves to view the inside of the body. Because ultrasound images are captured in real time, these images can also show the movement of the body's internal organs as well as fluid flow (e.g., blood flowing through blood vessels). In sonography, an imaging device (i.e., a transducer, probe, or transducer probe) can be placed directly on the skin or inside a body orifice (e.g., endovascular ultrasound, intravascular ultrasound, intracardiac echocardiography). The final quality of the image obtained through ultrasound scanning is limited by the technical specifications of the equipment, the propagation of ultrasound through the tissue being analyzed, and the method used to reconstruct the image.

[0089] (Ultrasound Imaging System) The systems, devices, and methods of the present invention address the interconnect challenges and methods for efficient and flexible transmission and reception of ultrafast ultrasound signals using flexible arrays. The systems and devices of the present invention provide novel imaging arrays and corresponding system architectures that solve these problems and provide ultrafast imaging in both in-plane and out-of-plane apertures.

[0090] As described in further detail below, in some embodiments, the present invention provides a system for optimizing an imaging aperture using a novel imaging array transducer with matrix addressing and bias activation, which allows for fewer interconnects while providing flexibility for imaging with convex aperture selection and optimization. In some embodiments, this combination enables a flexible, ultrafast imaging catheter with a cylindrical imaging array in a small form factor and improved imaging contrast, resolution, and sensitivity compared to other catheter systems that use 2D planar arrays.

[0091] The systems and devices of the present invention may be manufactured and / or assembled using current approaches. The systems and devices of the present methods may be operatively connected to an ultrasound system with specific hardware and software for providing image reconstruction and imaging assembly control, for example, as described in International PCT Application No. PCT / IB2019 / 000963 (published as WO2020 / 044117) to Hennersperger et al., U.S. Application Publication No. US2022-0287679A1 to Hennersperger et al., and U.S. Patent No. 11,382,599 to Hennersperger et al. (the contents of each of which are incorporated herein by reference in their entirety).

[0092] 1A and 1B are schematic diagrams of an exemplary ultrasound system 100 that may be used in conjunction with the systems and devices of the present invention, for example, to provide visualization and characterization of the vasculature within a patient 12. Generally, system 100 includes an imaging catheter 102 equipped with an imaging assembly 104 and an ultrasound console 106 to which imaging catheter 102 is connected.

[0093] FIG. 2 is a perspective view of an imaging catheter 102 to which the device may be coupled. The catheter 102 may include a catheter body 108 including proximal and distal portions. An imaging assembly 104 may be provided at the distal portion, for example, generally defining the distal end of the imaging catheter 103. A handle 110 may be operably associated with the catheter body 108 to enable an operator (i.e., a surgeon or other medical professional) to manipulate and advance the imaging assembly 104 and catheter body 108 to a desired target site within a patient's vasculature. The handle 110 may include user-operable inputs to control various features and functions of the imaging assembly 104. An interface member 112 may be provided at the distal portion of the catheter body 108. The interface member 112 generally provides a connection between the imaging catheter 102, including the imaging assembly 104 and handle 110, and the console 106 for the transmission of signals therebetween. The connection may include, for example, at least one of a wired connection and a wireless connection.

[0094] (ultrafast ultrasound imaging) Ultrafast ultrasound imaging techniques such as plane wave or diverging wave imaging may be required to enable imaging within the application constraints, particularly for intravascular and / or intracardiac tissue imaging. The systems, devices, and methods of the present invention enable the direct utilization of all native ultrafast imaging techniques.

[0095] For example, with respect to intracardiac imaging, plane wave imaging may refer to an ultrasound imaging modality through planar transmission of all transducer elements (at different angles) from an angular imaging aperture, where the plane wavefront may traverse tissue and be partially scattered back to the transducer. From the received radio frequency (RF) (i.e., channel) data, a global image may be reconstructed by dynamically beamforming the received RF data for each target location in parallel at once. In contrast to the present invention, other (native 3D) transducer arrays presented in the literature for intracardiac imaging do not enable the generation of full-angle aperture imaging, nor do they enable complete 360-degree coverage around the catheter, both of which are essential prerequisites for accurate depth and continuous / persistent monitoring of cardiac treatments such as ablation.

[0096] Ultrafast ultrasound methods provide imaging at thousands of frames per second, limited only by the physical propagation speed of sound waves in tissue, enabling ultrasensitive blood flow tracking, shear wave imaging, super-resolution imaging, and other applications. For example, achieving optimal spatial resolution while enabling artifact-free imaging of dynamic cardiac structures requires a careful balance between spatial sampling and volumetric update rate, which can only be achieved using ultrafast imaging techniques.

[0097] However, ultrafast imaging has been limited to 2D imaging, primarily involving rigid linear array transducers. While 2D array transducers enable 3D ultrasound imaging, they present a difficult engineering tradeoff between system complexity and achievable image quality. This is, in part, because plane wave (or diverging wave) imaging does not use a focal point for ultrasound signal transmission; rather, it simultaneously excites all elements in the array for ultrasound signal transmission at different angles, and focusing to the focal point is implemented in software using all received data for one or more ultrafast transmit and receive events. As a result, ultrafast imaging requires full electrical connections from each transducer element to a separate imaging channel so that all transducer elements are utilized in parallel for both transmit and receive modes.

[0098] To achieve a flexible imaging array capable of full-circumference imaging, sampling requires a high element count both laterally (e.g., along the length of the cylinder), with a pitch d smaller than the wavelength, and also in the elevation direction (e.g., around the circumference of the cylinder), with an angular spacing α determined by both the wavelength and the angular beam profile. In signal processing, sampling is the reduction of a continuous-time signal to a discrete-time signal. Sampling, in this context, refers to the conversion of an acoustic wave into a sequence of samples, each having a value of the signal at a point in time and / or space.

[0099] The requirement for a high element count to achieve the necessary sampling results in tens of thousands of elements, leaving limited space for electronics, making connections to each element impossible. 2 An array with NxN channels using elements is N 2 channel connections, which would quickly become impractical for large arrays or for invasive probes where cable and probe size must be small.

[0100] To illustrate this point, consider a center frequency of 8 MHz for a 15 mm long cylindrical array. For a wavelength of 0.195 mm, the maximum possible pitch d of elements is 0.18 mm (with limited ultrafast capabilities), and the ideal pitch is less than 0.0975 mm. This results in 84 lateral imaging elements per row (Nr) (154 elements each for the ideal case). For a full-circumference array with 1 degree elevation spacing, the total elevation imaging elements per column (Nc) is 360. The total number of elements (Nr × Nc) is 30,249. Connecting each element requires a total number of connections that are currently impossible, leaving only limited space to drive the electronics. Therefore, wired transmission of all data is not possible without combining multiple signals (digital or analog) into a single composite signal (multiplexing), which is then transmitted.

[0101] As a result, implementing a fully wired array is currently very difficult; for example, commercial (non-microbeamformer) arrays are available with only a limited number of elements. Using smaller arrays to address interconnection challenges results in small aperture sizes, which limit the achievable spatial resolution and contrast, resulting in poor or limited image quality, particularly in compact applications. Larger probes with high element density can be used to address image quality and produce high-quality images. However, a larger number of channels leads to significant interconnection and channel count challenges, making them impractical for compact applications. Several approaches have been attempted to reduce the channel count while achieving larger aperture sizes (e.g., multiplexing or sparsely distributing active elements with limited channels), but these methods have demonstrated sidelobe artifacts that degrade image quality.

[0102] Certain steps, such as subaperture beamforming (microbeamforming), can be directly integrated with the imaging array, simplifying the imaging interconnect. However, while this may work for scanline-based or focused imaging approaches, performance for ultrafast (plane wave / diverging wave) sequences is significantly degraded with this configuration because subaperture beamforming assumes the transmission of focused waves with a given focal point, and therefore delays may be applied within the subaperture, causing constructive wave interference and therefore the effective subaperture beamforming.

[0103] Monolithic integration of the complete imaging chain and imaging array has also been used to process the data entirely in the array before transferring it to the system in digital and processed form, however, due to the processing in hardware this limits the flexibility and adaptability for using different imaging modes and also creates significant challenges for large arrays in terms of heat dissipation and thermal management (both of which remain significant challenges in small probes).

[0104] Matrix-addressed arrays have been proposed to limit the cabling required and allow specific individual elements to be triggered by combining transmit on rows and receive on columns. However, previously proposed imaging designs have suffered from speed and / or image quality issues and have only been successful with rigid (non-flexible) 2D arrays, as described, for example, in Sobhani, 2022, Ultrafast orthogonal row-column electronic scanning (uFORCES) with bias-switchable top-orthogonal-to-bottom electrode 2D arrays, IEEE Trans Ultrason Ferroelect Freq Cont 69(10):2823-2835.

[0105] Furthermore, while plane wave and diverging wave imaging eliminate the need to form scan lines and cover larger areas, the loss of signal-to-noise ratio in image resolution necessitates having more data processing and filtering to improve these parameters. For example, wireless transmission of raw data from the ASIC in the catheter tip, with all elements receiving in parallel, requires tens of gigabytes per second to be transmitted in real time. Because the data rate requirements are enormous, wireless data transmission is not possible for the required distance between the probe inside the body and the external device. In the above example, the raw data rate is 141 Mbytes per shot, resulting in tens of gigabytes per second, which is not possible for standard wireless transmission.

[0106] Figure 3 illustrates a prior art ASIC design 300 for a matrix array probe. These designs have smaller elements, such as sub-apertures and sub-aperture processors. These sub-apertures perform local delay and summation (receive beamforming) and limit the required data channels to the receive side. This limits the flexibility for beamforming and can only support pre-designed delay schemes, such as scan line, pulse-echo, and pulsed Doppler.

[0107] Therefore, to achieve high-quality image resolution at ultrafast imaging, a major challenge for current application-specific integrated circuits (ASICs) in flexible matrix array ultrasound systems is the wiring congestion required for fully wired, high-density 2D arrays as the number of channels increases.

[0108] (New imaging array) The present invention recognizes that having good sampling for a flexible ultrasound imaging array capable of ultrafast imaging requires a high imaging element count. In contrast to rigid arrays, where the array can be integrated directly with the underlying imaging or processing ASIC, for example through the same process technology or through inverted chip bonding, flexible arrays do not allow for geometric integration into the rigid ASIC underneath, and therefore signal interconnects are more difficult for such designs.

[0109] The systems, devices, and methods of the present invention address the interconnect challenges and methods for efficient and flexible transmission and reception of ultrafast ultrasound signals using flexible arrays. The systems and devices of the present invention provide novel imaging arrays and corresponding system architectures that solve these problems and provide ultrafast imaging in both in-plane and out-of-plane apertures.

[0110] Specifically, the systems and devices of the present invention include imaging arrays and system architectures capable of matrix addressing and bias aperture selection for ultrafast imaging. As described in further detail below, the systems and devices of the present invention use bias selection and adjustment for row (or column) activation in combination with matrix addressing to define an angular imaging aperture that enables flexible imaging protocols, particularly for modes (plane wave and diverging wave) for ultrafast imaging. Prior art attempts at matrix addressing have been successful only for rigid 2D arrays and focused wave imaging.

[0111] The systems and devices of the present invention provide access to specific imaging elements as needed without implementing fixed subaperture operation. Thus, with the arrays of the present invention, elements do not have subaperture beamforming; instead, they receive all data at once. Importantly, the present invention provides matrix activation for any number of rows and / or columns on the imaging array to define the angular imaging aperture. This allows for activation of single or multiple rows at a time, depending on the intended and / or evaluated imaging aperture, particularly with circumferential apertures. This is not possible with classical signal multiplexing circuits.

[0112] Additionally, different bias voltages may be used to tune the imaging frequency higher or lower, or to combine adjacent rows and / or columns with differently tuned frequencies for harmonic tuning.

[0113] (Angular imaging aperture) The present systems and devices provide flexible imaging arrays capable of ultrafast imaging. To define and optimize the angular imaging aperture, the present systems and devices allow access to imaging elements as needed without fixed motion of subapertures. Importantly, using matrix addressing to define (i.e., adjust) the array's imaging aperture, particularly the angular imaging aperture, applies to any convex array surface with a specific radius. For example, the concept may be applied to a convex surface around the entire imaging probe, i.e., the special case of a cylindrical surface. Thus, in some embodiments, the angular imaging aperture may be understood to mean the angular direction along the curvature.

[0114] Figure 4 illustrates a schematic diagram of the physical sensitivity of imaging elements in the radial direction around a cylindrical array catheter in some embodiments of the present invention. The cylindrical shape (or the radius of the cylinder) provides geometric boundary constraints on which elements can receive data for a point in space. For active elements, the physical sensing aperture of the element is illustrated. Sensitivity describes the electrical-to-transducer energy conversion efficiency and is an important indicator of transducer performance. Generally, sensitivity is defined as the ratio of the output quantity to the input quantity.

[0115] An aperture is an active area that transmits or receives acoustic waves at a particular moment. For a single-element transducer, the aperture size is the transducer element size. For a transducer with an array of elements, the aperture is all elements that are simultaneously active. Generally, as understood, ultrasound imaging has spatially varying resolution depending on the size of the transducer's active aperture (including the dimensions of each ultrasonic element), the transducer's center frequency and bandwidth, and the selected transmit pattern. For focused imaging, lateral resolution is best at the focal distance and spreads non-uniformly away from this distance due to diffraction effects caused by the aperture, which is about a few to about a few tens of wavelengths. For unfocused imaging, such as plane wave or diverging wave imaging, lateral resolution for transmit spreads away from the transducer surface because focusing is performed using multiple transmit waves.

[0116] FIG. 5 illustrates the active radial apertures for radial rows around a cylindrical imaging catheter in one embodiment of the present invention. The active aperture depends on the angular coverage of each physical element (i.e., the directivity of the imaging element). Each ultrasound transducer has its own specific directivity pattern. The directivity pattern, also known as the beam pattern or radiation pattern, is an important far-field characteristic of the transducer. The directivity pattern consists of a main lobe and side lobes. Because the radiation intensity is primarily dominant in the area in front of the transducer source, the main lobe is directly in front of the ultrasound transmitter, followed by side lobes to the sides, with null regions between these lobes. In general, the directivity pattern is the same whether the transducer is used as a transmitter or a receiver.

[0117] The present invention provides systems and devices involving flexible imaging arrays that allow flexibility in convex aperture selection and optimization. The present invention takes advantage of the fact that convex arrays, including cylindrically shaped arrays, provide geometric boundary constraints on which elements can receive data about a point in space. For example, the angular imaging aperture of a cylinder results in limited angular coverage of ultrasound waves emitted from and received by the flexible imaging array. Specifically, imaging of a particular side or view from a cylindrical catheter may be sequential, not the entire cylinder at once, due to the radial aperture. This means that full sampling of multiple rows around the circumference of a cylindrical array would not result in improved circumferential resolution.

[0118] The present invention uses this concept to define an angular aperture of a defined number of rows, for example, from one row to a group of multiple rows. In this way, the systems and devices of the present invention allow for a desired aperture based on the geometry of the ideally emitting ultrasound imaging array. For example, all of the elements of the array may be used along the array. Alternatively, out-of-plane, the aperture may be, for example, three to five rows, depending on the element pitch, which allows for a larger aperture and increased circumferential resolution.

[0119] This combination of matrix addressing and bias activation and adjustment achieves an angular imaging aperture for full 360-degree ultrafast imaging. In certain embodiments, this concept enables a flexible ultrafast imaging catheter with a cylindrical imaging array, which provides improved imaging contrast, resolution, and sensitivity compared to other catheter systems that use planar 2D arrays. Thus, the present invention provides full 360-degree circumferential ultrafast imaging, which was not previously possible.

[0120] It should be noted that the systems and devices of the present invention are also applicable to planar 2D arrays, as explained in detail below.

[0121] 6A and 6B illustrate side and cross-sectional views of one embodiment of a cylindrical imaging array of the present invention. The cylindrical imaging array provides a high element count in both the lateral direction (e.g., along the length of the cylinder) with a pitch d and in the elevation direction (e.g., around the circumference of the cylinder) with an angular spacing α. Thus, the flexible imaging array is capable of achieving full-circumference imaging.

[0122] Flexible imaging arrays for ultrafast ultrasound imaging may be configured for any shape, e.g., cylindrical / non-cylindrical, flat and non-flat. As noted above, the flexible arrays of the present invention allow for defining and optimizing angular apertures for surfaces of any shape, particularly for concave surfaces (e.g., cylindrical arrays). However, in some embodiments, the present system architecture may be used for rigid imaging arrays, e.g., rigid convex / cylindrical arrays, that are capable of defining specific angular imaging apertures for full 360-degree imaging.

[0123] It should be noted that the particular description of the present invention focuses on using the systems and devices of the present invention for ultrasound visualization of intravascular and / or intracardiac tissue, which may be particularly useful for catheter-based interventional procedures for assessing anatomical and functional data relative to a target volume of interest. In general, however, it should be understood that the devices, systems, and methods of the present invention may be used for ultrasound visualization of any type of tissue for any type of procedure in which imaging analysis is used and / or preferred.

[0124] An aspect of the present invention provides a system for optimizing an imaging aperture, including a controller operatively associated with an imaging device. The imaging device includes a transducer with an array of individual imaging elements arranged vertically along the transducer in multiple rows and horizontally along the transducer in multiple columns. As described in further detail below, signal connectivity of the individual imaging elements is defined by row and column addresses of the array. The device includes a plurality of first electrodes connecting with the rows of individual imaging elements and a plurality of second electrodes arranged at a non-zero angle relative to the plurality of first electrodes such that each second electrode connects with a column of individual imaging elements. The controller is coupled to a non-transitory computer-readable memory including instructions executable by a processor to cause the controller to selectively apply bias voltage levels to one or more of the plurality of first electrodes and the plurality of second electrodes. The bias voltage levels thus define voltages for the rows or columns connected to the electrodes, activating or deactivating imaging by the individual imaging elements in the row or column and defining the angular imaging aperture.

[0125] In the present invention, the transducer may be of any type for transmitting and receiving acoustic waves. For example, the transducer may include one- or two-dimensional arrays of electronic transducer elements to transmit and receive acoustic waves. These arrays may include microelectromechanical systems (MEMS)-based transducers, such as capacitive micromachined ultrasonic transducers (CMUTs) and / or piezoelectric micromachined ultrasonic transducers (PMUTs).

[0126] CMUT devices offer superior bandwidth and acoustic impedance characteristics, making these transducers preferable to traditional piezoelectric transducers. The vibration of the CMUT membrane can be triggered by applying pressure (e.g., using ultrasound) or can be triggered electrically. Electrical connections to the CMUT device, often using an integrated circuit (IC) such as an ASIC, facilitate both the transmit and receive modes of the device. In the receive mode, a change in membrane position causes a change in electrical capacitance, which can be electronically detected; while in the transmit mode, applying an electrical signal causes the membrane to vibrate.

[0127] Piezoelectric micromachined ultrasonic transducers (PMUTs) are based on the flexural motion of a thin membrane coupled to a thin piezoelectric film such as PVDF. This contrasts with bulk piezoelectric transducers, which use thickness-mode motion of a plate of piezoelectric ceramics such as PZT or single-crystal PMN-PT. Compared to bulk piezoelectric ultrasonic transducers, PMUT devices offer advantages such as increased bandwidth, flexible geometry, natural acoustic impedance matched to water, reduced voltage requirements, and the ability to mix different resonant frequencies and potentials for integration with supporting electronics, especially for miniaturized high-frequency applications. Current PMUT devices may not require biasing to achieve imaging sensitivity.

[0128] In some embodiments of the system of the present invention, the transducer may be a microelectromechanical system (MEMS)-based capacitive micromachined ultrasonic transducer (CMUT) configured as a two-dimensional (2D) array structure. In a non-limiting example, the 2D array may be a flexible structure. The device of the present invention may include a cylindrical imaging array, which in a CMUT design consists of a flexible 2D array structure. Flexible MEMS-based arrays may be implemented by wafer thinning (CMUT / PMUT) or by using specific approaches such as combining rigid imaging cells with flexible interconnects, as described, for example, in Mimoun, 2013, "A generic platform for the fabrication and assembly of flexible sensors for minimally invasive instruments," IEEE Sensors J 13(10) 3873-3882 (incorporated herein by reference).

[0129] Additionally and / or alternatively, the transducers may be made from electrostrictive materials configured as a two-dimensional (2D) array structure. Electrostriction is a property of all dielectric materials and consists of mechanical displacement in response to an electric field, such as material compression in a region of high electric field strength. In electrostriction, an electric field applied to a material produces a deformation of the material (direct effect), and a mechanical stress applied to a material changes the polarization of the material (reverse effect). Transducers of the present invention may be made from electrostrictive materials, such as electrostrictive polymers, or any material that can be activated using a bias voltage to achieve imaging sensitivity.

[0130] (row and column addressing) The present invention uses matrix addressing in combination with bias activation to achieve an angular imaging aperture for ultrafast ultrasound imaging. Specifically, the system of the present invention employs matrix addressing to adjust the imaging aperture. Instead of connecting each element individually, all elements in a row and column are connected together, allowing for addressing of the elements in a matrix manner. For example, a front electrode on the imaging array may address a column (or a "ring" on a cylindrical array), and a back electrode on the imaging array may address a "row." However, it should be noted that the front and back electrodes of the imaging array may be switched for ring / row addressing, respectively.

[0131] For example, the plurality of first electrodes may be positioned as back electrodes and the plurality of second electrodes may be positioned as front electrodes, or the plurality of first electrodes may be positioned as front electrodes and the plurality of second electrodes may be positioned as back electrodes.

[0132] For clarity, a "ring" may refer to imaging elements arranged circumferentially around a cylindrical array, or alternatively, may be referred to as a column on the array. Similarly, a "row" may refer to imaging elements arranged longitudinally along the transducer. Thus, individual elements may be referred to as being in a row and / or column / ring, and each individual element would have a row and / or column address, e.g., (i, j).

[0133] Matrix addressing allows the system to address each imaging element of the array through a row and column scheme, which reduces the amount of interconnects from Nr x Nc for a fully connected array to Nr + Nc connections for matrix addressing. As an example, an imaging array with 64 rows and 180 columns would require (64 x 180) = 11,520 connections for a fully connected array. Using the matrix addressing of the present invention, the array would require only (64 + 180) = 244 connections, thus significantly limiting the number of interconnects required.

[0134] 7 illustrates an embodiment of an imaging array 700 of the present invention. For example, the present invention provides a flexible imaging array and system architecture that provides row and column addressing, with front electrodes addressing rings or columns and back electrodes addressing rows. The device of the present invention supports ultrafast imaging within an aperture, both in-plane and out-of-plane.

[0135] FIG. 8 illustrates an embodiment of a cylindrical imaging array 800 of the present invention.

[0136] 9 illustrates classical matrix addressing. In this concept, the transmit function is achieved on one set of electrodes and the receive function is achieved on orthogonal electrodes; specifically, the transmit function is performed on a complete row and the receive function is performed on a column to address a specific imaging element. Until the present invention, classical matrix addressing was only possible for transmit and receive on orthogonally positioned electrodes.

[0137] The angular imaging aperture may be defined as one or more rows or one or more columns of the imaging array based on the beam aperture sensitivities of the individual imaging elements of the array. For example, the angular imaging aperture may be defined as one row or one column to about ten rows or columns. The individual beam aperture sensitivities may be known so that this value is included in the calculation of the desired angular imaging aperture. The individual beam aperture sensitivities of the imaging elements may be obtained through measurement and / or simulation.

[0138] (bias activated) The present invention takes advantage of the fact that for modern MEMS-based capacitive arrays, such as capacitive micromachined ultrasonic transducers (CMUTs), the bias voltage required by the CMUT array not only allows for frequency tuning of the target imaging frequency, but also allows for deactivation of the elements due to their high attenuation / decreased sensitivity when the bias is deactivated. The present invention recognizes that CMUT arrays require a bias voltage to be supplied through one of the electrodes, which can be the back electrode or the front electrode, in order to operate the CMUT elements efficiently.

[0139] The present invention provides for the use of bias voltages to adjust the frequency range of an imaging array, with the sensitivity for a certain frequency range being driven by the bias voltage. The bias voltage may also be used to completely deactivate imaging elements. Importantly, using bias voltages to activate imaging elements (i.e., cells) enables imaging without multiplexing. Thus, the present invention provides for the use of matrix addressing on the back (or front) electrodes to control the bias voltages applied to the imaging elements and dynamically activate specific groups of elements or adjust their frequency range sensitivity.

[0140] 10 illustrates an embodiment of biased row activation in a device of the present invention. In contrast to classical matrix addressing, the present invention uses bias activation to provide complete activation or deactivation of individual rows and columns. The present invention combines both classical matrix addressing and biased row activation concepts to, for example, control both the angular imaging aperture and imaging mode in a CMUT array.

[0141] Bias activation means that imaging will be activated on a given row or column when a nominal bias voltage is applied to tune the imaging array to a target center frequency. Similarly, applying a bias voltage of 0V or a voltage level to which the imaging elements are minimally sensitive will deactivate the imaging row or column. This allows for enabling or disabling complete rows or columns on the array, providing for flexible transmit / receive schemes on the activated rows and / or columns.

[0142] The bias voltage may be applied to the front electrode or the back electrode. As an example, with Nr back electrodes, the electrodes may address rows for transmission and reception. The bias voltage may be applied based on the row address and / or column address of one or more of the individual imaging elements. Additionally, the bias voltage may be applied to activate imaging in one or more rows. Similarly, the bias voltage may be applied to activate imaging in one or more columns.

[0143] A bias voltage of 0 V may be applied to deactivate a row, i.e., attenuating the element sensitivity to -60 dB. For example, applying a bias voltage of 0 V or a voltage level at which the imaging element sensitivity is minimal may deactivate imaging in a row or column. Additionally, one or more columns and / or one or more rows may be deactivated.

[0144] In addition, the bias voltage may be adjustable to adjust the frequency of the imaging element. In particular, the bias voltages selectively applied to the plurality of first electrodes and the plurality of second electrodes may be the same or different for each electrode, allowing the imaging frequency of the imaging element to be adjusted higher and / or lower to achieve a desired frequency.

[0145] For example, a bias voltage of 35 V may be applied to the row as a nominal voltage (adjusted for 10 MHz imaging). Bias adjustment (up or down) may be used to adjust the center frequency. Nc front electrodes may address the columns / rings for transmission and reception. Thus, a transmit pulse may be sent and data may be received for all rings / columns in a selected row. This allows elements in a row to be addressed as single elements. As a result, positive and / or negative bias voltage levels selectively applied to the multiple first electrodes and / or multiple second electrodes may adjust the imaging operation mode.

[0146] Alternatively, the matrix array architecture of the present invention may be addressed as a classical matrix array, e.g., transmit ultrasound on selected rows and receive on selected columns, which allows for the use of synthetic aperture type imaging with cylindrical arrays.

[0147] Additionally, a bias voltage applied to the first electrode may activate an imaging element connected to the second electrode for both transmit and receive functions.

[0148] 11 illustrates an embodiment of the system architecture of the present invention in which the transmit function can be activated by the bottom electrode and the receive function can be activated on the top electrode. The imaging array system includes a bias tee to provide a DC current or voltage to bias the RF circuitry.

[0149] The system of the present invention provides a device having a plurality of first electrodes connecting to rows of individual imaging elements and a plurality of second electrodes arranged at a non-zero angle relative to the plurality of first electrodes. The plurality of second electrodes may be arranged orthogonally relative to the plurality of first electrodes. For example, as illustrated in FIG. 11, the transmit and receive functions may be on the same electrode, with activation of individual elements through bias (on / off) on the orthogonal electrode. This, in combination with the orthogonal electrodes, allows for addressing of individual elements by bias voltage. Note that the transmit and receive functions may be on the same electrode or on orthogonal electrodes.

[0150] Importantly, the second set of electrodes may not be orthogonal to the first set of electrodes, but may instead be at any non-zero angle relative to the first set of electrodes. Furthermore, the front and / or back electrodes may be switched in terms of interconnection (bias injection vs. AC signal for transmission function).

[0151] In a non-limiting example, a bias voltage applied to the first electrode may activate (i) the receive function of each imaging element connected to the first electrode and the transmit function of each imaging element connected to the second electrode, or (ii) the transmit function of each imaging element connected to the first electrode and the receive function of each imaging element connected to the second electrode.

[0152] Additionally, a bias voltage applied to the second electrode may activate (i) the receive function of each imaging element connected to the second electrode and the transmit function of each imaging element connected to the first electrode, or (ii) the transmit function of each imaging element connected to the second electrode and the receive function of each imaging element connected to the first electrode.

[0153] Additionally, a bias voltage applied to the first electrode may activate the transmit or receive functions of individual imaging elements connected to the first electrode and the transmit or receive functions of individual imaging elements connected to the second electrode.

[0154] 12 illustrates a non-limiting example of row activation in one embodiment of a flexible imaging array of the present invention. In an example, a bias voltage of 35V may be applied to selected backside electrodes to tune the imaging array to a target center frequency such that imaging is activated on that row. Selected surrounding rows may be deactivated by applying a bias voltage of 0V and / or a voltage to those selected rows such that the sensitivity of the imaging elements in those rows is minimal.

[0155] FIG. 13 illustrates a non-limiting example of column / ring activation in one embodiment of a flexible imaging array of the present invention. Applying a bias voltage of 0 V or a voltage level to which the imaging elements are minimally sensitive can deactivate imaging within a row or column. In this example, a bias voltage of 35 V may be applied to a selected column or ring to activate the column / ring. Selected surrounding columns may be deactivated by applying a bias voltage of 0 V and / or a voltage to which the imaging elements are minimally sensitive. In this manner, one or more columns and / or one or more rows may be deactivated.

[0156] This allows for the activation of single or multiple columns at a time, depending on the intended and / or evaluated imaging aperture, particularly with respect to the angular aperture. It is noteworthy that this is not possible with classical signal multiplexing circuits. Additionally, different bias voltages may be used to tune the imaging frequency higher or lower, or to combine adjacent rows and / or columns with differently tuned frequencies for harmonic tuning, allowing for flexible acquisition schemes and improving imaging contrast and resolution.

[0157] FIG. 14 illustrates an embodiment of multiple row activation of an imaging array of the present invention. It is noteworthy that multiple adjacent rows, in this case, three adjacent rows, may be tuned to the same center frequency. In this embodiment, the back electrode may activate Nr rows, and the front electrode may activate Nc rings / columns. A bias voltage of 0V (and / or a voltage to which the imaging elements are minimally sensitive) may be applied to rows that are not activated. This concept may be applied for ring / column activation as well. Importantly, the total number of interconnects is Nr + Nc, which results in a much smaller number of connections for arrays with a high number of elements in the rows (Nr) and columns (Nc).

[0158] FIG. 15 illustrates an embodiment of frequency tuning of multiple active rows in an imaging array of the present invention. In this example, a rear electrode may activate Nr rows, and a front electrode may activate Nc columns / rings. Selected rows may be activated and tuned to a center frequency, while selected adjacent rows may be tuned to a matched frequency. Other selected rows may be deactivated by applying a bias voltage of 0V and / or a voltage to which the imaging elements are minimally sensitive. As again illustrated, the total number of interconnects to achieve the desired frequency tuning for the angular aperture is Nr + Nc. Thus, in a system of the present invention, the angular imaging aperture may be defined by the number of rows (Nr) and / or columns (Nc) to which bias voltages are applied, and the number of interconnects between imaging elements may be Nr + Nc.

[0159] As described above, the bias voltage level may be adjustable to adjust the frequency of the imaging element. Furthermore, the bias voltage levels selectively applied to the plurality of first electrodes and the plurality of second electrodes may be the same or different for each electrode, allowing the imaging frequency of the imaging element to be adjusted higher and / or lower to achieve a desired frequency. In addition, the positive bias voltage and / or negative bias voltage level selectively applied to the plurality of first electrodes and / or the plurality of second electrodes adjusts the imaging operation mode.

[0160] Thus, using the principles described above, the use of matrix addressing of imaging elements in an array in combination with bias activation achieves a desired angular aperture for ultrafast imaging. Specifically, sequential application of varying transmit / receive / bias patterns during imaging enables targeted ultrafast imaging. As a result, the present invention provides angular aperture definition and optimization for ultrafast imaging that is not limited to a 90 x 60 degree sector aperture for pyramidal volumetric views.

[0161] (Array Element Interface and System Architecture) The bias voltage selectivity of the imaging systems and devices of the present invention is controlled by a controller that controls the bias voltages selectively applied to one or more of the plurality of first and / or second electrodes, and can activate or deactivate imaging by individual imaging elements in a row or column and define an angular imaging aperture.

[0162] The controller may include one or more interfaces, for example, operatively connecting the controller to the aspects of the array and imaging electronics, generating transmit pulse waves, and converting sensor changes into equivalent voltages or currents once wave data is received. The controller may also directly include these aspects of transmit and receive control (analog front end). The controller may also be capable of controlling transmit and receive wave patterns for flexible imaging, or these capabilities may be otherwise integrated. The system of the present invention may include multiple interface modules, with each module operatively connected to both the controller and one electrode connecting to a row or column.

[0163] In some embodiments, the devices of the present invention comprise multiple interface modules, such that each module is operatively connected to both the controller and one electrode connecting to a row or column.

[0164] 16A and 16B illustrate a schematic diagram of one embodiment of an interface for a row of elements in an array. FIG. 16B shows an expanded view of the circuit diagram of FIG. 16A. For example, the controller may include an interface for each electrode connecting with a row of individual imaging elements, such that the bias voltage applied to the electrode is enabled, disabled, or defined by the interface. The controller may include an interface for each electrode connecting with a column of individual imaging elements, such that the bias voltage applied to the electrode is enabled, disabled, or defined by the interface. These examples should be understood as non-limiting in that a system of the present invention may include multiple interface modules, such that each interface module is operably connected to both the controller and one electrode connecting with a row and / or column.

[0165] 17A and 17B illustrate a schematic diagram of one embodiment of an imaging array element interface for a particular row and a particular column, e.g., row i and column j, which provides a transmit or receive address for, e.g., the (i, j) element. FIG. 17B shows an expanded view of the circuit diagram of FIG. 17A. Interfaces may be included for matrix addressing by row and / or column, and interfaces may be included for bias activation of each column and / or row.

[0166] Figures 18A and 18B illustrate an embodiment of the invention in which each row of an imaging array is connected to an individual array element interface, as are each column of the array, so that individual imaging elements can be addressed for transmission and / or reception by row and column (row, column) addresses. Figure 18B shows an expanded view of the circuit diagram of Figure 18A.

[0167] 19A and 19B further illustrate an embodiment of an interface circuit with bias voltage selection, showing the interface circuit for an imaging element in row i and column j, i.e., the imaging element at address (i, j). FIG. 19B shows an expanded view of the circuit diagram of FIG. 19A. For bias voltage selection, each row and each column bias voltage may be individually enabled, disabled, or set using a digital-to-analog converter (DAC) specific to each imaging element. The DACs may be addressable via a common transmit (Tx) and voltage bias (Vbias) control serial bus.

[0168] The controller may also include protection circuitry operatively connected in series with each row and column of individual imaging elements so that multiple bias voltage levels cannot be applied to a given electrode simultaneously. For example, the protection circuitry may be a fuse or a circuit breaker or other circuit protection device. In some embodiments, the ORing circuitry utilizes diodes and / or transistors.

[0169] As an example, one or more ORing diodes may be placed in series with each DAC output to protect each element from simultaneous activation of the bias voltages at its row and column address locations. In this example, the ORing diodes are in series with the DACs to protect the element at address (i,j) from simultaneous activation of Vbias_i and Vbias_j. For non-CMUT elements, the DACs may be disabled to achieve Vbias_i = Vbias_j = 0V.

[0170] In some embodiments, the one or more bias voltage selection circuits are connected to the controller using one or more multipoint communication interfaces. In some embodiments, control of the transmit and / or receive functions uses one or more interfaces that are common to or separate from the interface used for bias voltage selection.

[0171] The controller may include a computer program comprising an algorithm 201 for evaluating, calculating, and optimizing the angular imaging aperture. For example, using the defined algorithm, the controller may be configured to provide feedback to an operator before or during operation of the imaging array to evaluate, calculate, and optimize the angular imaging aperture. The controller may also be configured to provide feedback after operation of the imaging array. The algorithm 201 may be part of a computer program executable by a computing system 203 and in communication with a controller of the imaging device.

[0172] The controller may be configured to activate single or multiple rows at a time using the same or different bias voltage levels to achieve an optimized angular imaging aperture.The controller may be configured to activate single or multiple columns at a time using the same or different bias voltage levels to achieve an intended angular imaging aperture.

[0173] The controller may be configured to control different activation and / or adjustment schemes for each individual transmit / receive event, and multiple transmit / receive events may have the same or alternating schemes, allowing for a flexible beamforming approach.

[0174] 20 illustrates an embodiment of an imaging device 200 of the present invention in which a controller 205 is in active communication with a computing system 203 that includes an algorithm 201 for evaluating, calculating, and optimizing the angular imaging aperture. The device may be operatively connected to an imaging assembly 104 that interfaces with an ultrasound system 100, as described in detail above. Thus, the controller, in active communication with the computing system, may be configured to activate single or multiple rows at a time using the same or different bias voltage levels to achieve an optimized angular imaging aperture.

[0175] The controller may be configured to activate multiple individual imaging elements simultaneously based on the row and column address locations of the individual imaging elements, and thus the simultaneously activated individual imaging elements may have the same or different bias voltage levels.

[0176] To activate a desired row of the imaging element, the controller may select a transmission address corresponding to the desired row and send a signal with a desired bias voltage level to the interface for the desired row. Similarly, to activate a desired column of the imaging element, the controller may select a transmission address corresponding to the desired column and send a signal with a desired voltage level for the desired column to the interface.

[0177] For example, to activate all elements in a row, transmission to only the desired row of elements may be achieved by selecting a transmission address on the Tx and VbiasControl buses. To activate all elements in row i, a transmission address corresponding to row i on the Tx and VbiasCtrl buses may be selected. This enables and sets the value of the row bias voltage. For row i, the bias voltage is designated as Vbias_i. Thus, the value of the row i bias voltage (Vbias_i) may be enabled and set. Furthermore, the column bias voltage for column j, designated as Vbias_j, may be disabled by setting Vbias_j equal to 0V for all columns. Notably, multiple rows may be activated simultaneously using the same or different bias voltage levels. In this manner, an imaging aperture for ultrafast imaging may be defined.

[0178] Similarly, to activate a single element in row i, column j (i.e., (i,j)), the system enables transmission to all row elements by selecting the address corresponding to row i on the Tx and Vbias control buses. All other row bias voltages may be disabled by setting Vbias_i equal to 0V for all rows. The bias voltage for column j (Vbias_j) may then be enabled and set.

[0179] To activate all elements in column j, the system selects all transmit (Tx) addresses on the Tx and Vbias control buses and then enables transmission to all elements by disabling all row bias voltages by setting Vbias_i equal to 0V for all rows. The column j bias voltage (Vbias_j) may then be enabled and set. In this manner, multiple columns may be activated simultaneously using the same or different bias voltage levels.

[0180] The controller may also include integrated circuits for bias voltage generation and control and other aspects of transmitting and receiving wave data (analog front-end circuitry). The integrated circuits may be housed in an enclosure along with the imaging elements or may be located on a substrate along with the imaging elements. For example, the substrate may be a flexible substrate such as a polymer substrate, a compliant silicone elastomer, or other material capable of housing both integrated circuitry as well as the imaging elements, as known to those skilled in the art.

[0181] The controller may be stored separately from the imaging element or may be operably coupled to the imaging element via circuitry, which may include at least one of one or more cable assemblies, one or more printed circuits, and / or one or more flexible printed circuits.

[0182] Additionally, the controller may also include an analog front-end circuit housed separately from the imaging element, including one or more signal generators and / or one or more signal transmitters, and / or one or more switching circuits, packaged separately from the imaging element or in a remote enclosure connected to the imaging element via a cable assembly. For example, the analog front-end circuit (i.e., a set of analog conditioning circuitry using high-sensitivity analog amplifiers) may use operational amplifiers, filters, or specific IC blocks for a sensor or other circuit to interface with the sensor, an analog-to-digital converter (ADC), or a microcontroller.

[0183] The systems and devices of the present invention may have more than one controller. For example, in addition to a controller that selectively controls the bias voltage, there may be a second (or the same) controller that transmits ultrasound pulses of a specific imaging frequency into tissue and then converts the received echoes into digital signals. This may be understood as an ultrasound analog front end that provides transmit and receive capabilities, which may be integrated with bias activation or implemented separately. Importantly, the transmit and receive functions of the ultrasound transmit and receive sequences may be controlled in synchronization with the controller for bias adjustment and selection, enabling intelligent beamforming.

[0184] In addition to the controller selectively controlling the bias voltage, the controller may also transmit ultrasound pulses at a particular imaging frequency into the tissue and then convert the received echoes into digital signals.

[0185] The systems and devices of the present invention provide flexible arrangements of controllers and associated components, flexibly accommodating various size embodiments of device designs to suit particular applications. For example, the controller's integrated circuit may be housed with analog front-end circuitry at the catheter tip adjacent to the imaging element. The integrated circuit may be housed with analog front-end circuitry operably coupled to and positioned directly adjacent to the imaging element. In some embodiments, the signal generator, signal transmitter, and / or switching circuitry are housed in a remote enclosure connected to the imaging element via circuitry. The circuitry may include, for example, a cable assembly, a printed circuit, and / or one or more flexible printed circuits.

[0186] FIG. 21 is a schematic diagram of another embodiment of a system of the present invention for producing ultrasound images using ultrafast imaging techniques.

[0187] As mentioned above, the multiple imaging elements may be acoustic sensors selectively activated by a controller based on row and / or column addresses of the acoustic sensors to transmit and / or receive multiple incident acoustic wave signals as wave data. The wave data may be, for example, at least one of plane wave data and diverging wave data associated with one or more plane wave transmit / receive cycles performed by the imaging elements. The active elements used for transmission and reception may comprise all elements in both transmission and reception, the same subset of elements used for transmission and reception, or different subsets (or complete sets) of elements used for transmission and reception of wave data.

[0188] The wave data may be full-circumference three-dimensional (3D) image data. For example, using matrix addressing in conjunction with bias activation, an array of acoustic sensors may be set to different transmit angular positions, thus transmitting multiple incident acoustic wave signals representing one or more plane waves of a group of plane waves, to help depict a 3D image over time.

[0189] The system transducer of the device may be cylindrical, and thus the array of individual imaging elements may be arranged in multiple rows longitudinally along the transducer and multiple columns circumferentially around the transducer. As noted above, the imaging array may include a number of rows (Nr), a number of individual imaging elements per row (Ne), a row spacing, and a number of columns (Nc), where the total number of imaging elements in the array is (Ne·Nr), and the individual imaging elements may be connected through a number of connections represented by Nr+Nc. The Nr connections may be used to transmit and receive ultrasound signals as ultrafast wave data, and the Nc connections may be used to control bias voltages to the elements.

[0190] Cylindrical transducers may have thousands of elements, enabling ultrafast plane wave or diverging wave imaging. For example, 64 columns (rings) and 1-degree angular spacing may result in 23,040 elements. Similarly, a cylindrical transducer may have 128 elements per row and 1-degree row spacing, resulting in 46,080 individual imaging elements. These elements may be connected through 488 connections (128 + 360), with 360 lines used to control bias voltages and 128 lines used to transmit and receive ultrasound signals as ultrafast wave data. Alternatively, both the 360 ​​lines and the 128 lines (for rows and columns) may be used for both transmitting and receiving bias and voltage signals. This number of connections can be easily managed using wired connections within the catheter, for example, through twisted pair, micro-coaxial, or flexible printed circuit cable assemblies. Thus, row (or column) activation allows flexible selection of groups of sub-elements (or rows of active elements) to define the angular imaging aperture.

[0191] The row spacing around the cylindrical array may be any planar angle. For example, the row spacing may be about 0.1 degrees to about 5 degrees in the angular direction. The number of rows required for diverging waves may depend on the row spacing (e.g., 5 degrees vs. 0.1 degrees) and the aperture of the imaging wave. In practice, the row spacing may be determined as a balance between the angular spacing (0.1 to 1 degree in the above example) and the geometric properties of the transducer elements and the pattern of the transducer elements. The size of the transducer elements may have a size or diameter of, for example, 10 to 150 micrometers, while the pattern may be appropriately selected to allow for the above spacing of 0.1 to 1 degree, as described above.

[0192] 22-25 and described above, a key differentiation of the present invention compared to other 2D array designs is that the present invention is not required to transmit / receive on the full array. In fact, this does not provide any benefit for imaging resolution due to the radial aperture, i.e., imaging of a particular side / view from the catheter may be sequential and not the entire cylinder at once.

[0193] FIG. 22 illustrates a cylindrical array transducer with 24 rows of elements radially around the transducer and a 9 element imaging aperture that can be used to image the side of the transducer.

[0194] Figure 23 illustrates the activation of a single element. Referring back to Figure 4, the physical sensitivity aperture of the activated element is illustrated. Further, referring back to Figure 5, the activation of three elements (or rows of elements) to define an active convex aperture is illustrated.

[0195] As noted above, a bias voltage may be applied to the first electrode and connected to the second electrode to activate transmit and / or receive functionality on the individual imaging elements such that the individual imaging elements transmit and / or receive ultrasound signals in the form of ultrafast wave data. In embodiments, the transducer array may include a number of individual imaging elements per row (Ne) in an array design that enables ultrafast plane wave and / or diverging wave imaging, such that plane wave and / or diverging wave imaging modes include capturing reflected signal data at a rate of at least 10 kHz.

[0196] Generally, the transducer probe and / or controller may be operably coupled to a console, which may generally control the operation of the transducer probe (i.e., transmission of acoustic waves from the probe) and / or the controller. The console may generally include one or more processors (e.g., a central processing unit (CPU), a graphics processing unit (GPU), or both) and storage devices, such as main memory, static memory, or a combination of both, which communicate with each other via a bus or the like. Memory according to embodiments of the present invention may include a machine-readable medium on which one or more sets of instructions (e.g., software) that embody any one or more of the methodologies or functions described herein are stored. Software may also reside, completely or at least partially, in the main memory and / or the processor during its execution by a computer system, with the main memory and the processor also constituting machine-readable media. Software may also be transmitted or received over a network via a network interface device.

[0197] For example, in an exemplary embodiment, the console may generally include a computing device configured to communicate across a network. The computing device may include one or more processors and memory, as well as input / output mechanisms (i.e., keyboards, knobs, scroll wheels, or the like) with which an operator can interact to operate the machine, including making adjustments to the transmission characteristics of the probe, saving images, and performing other tasks described herein, including selecting particular regions of interest for subsequent reconstruction into 2D and / or 3D images.

[0198] During operation, the CPU and / or GPU may control the transmission and reception of electrical current, which subsequently results in the emission and reception of acoustic waves from the probe. The CPU and / or GPU may also analyze the electrical pulses made by the probe in response to returning reflected waves and then convert this data into an image (i.e., an ultrasound image), which can then be viewed on a display, which may be an integrated monitor. Such images may also be stored in memory and / or printed via a printer. The console may further provide control of the imaging assembly, including control of the emission (intensity, frequency, duration, etc.) of ultrasound pulses therefrom as well as control of the movement of the ultrasound transducer unit.

[0199] (Method for optimizing the imaging aperture) 24 illustrates an embodiment of a method 2400 for imaging of the present invention, as described in some embodiments herein, including step 2401 of providing an imaging device, step 2403 of applying bias voltages to selected electrodes to activate or deactivate selected imaging elements, and step 2405 of defining an angular imaging aperture.

[0200] Aspects of the invention provide a method for imaging comprising providing an imaging device as described herein comprising: a transducer comprising an array of individual imaging elements arranged in a plurality of rows vertically along the transducer and in a plurality of columns horizontally along the transducer, wherein signal connectivity of the individual imaging elements is defined by a row address and a column address of the array; a plurality of first electrodes, each first electrode connecting with a row of individual imaging elements; a plurality of second electrodes arranged at a non-zero angle relative to the plurality of first electrodes, each second electrode connecting with a column of individual imaging elements; and a controller capable of controlling bias voltages selectively applied to one or more of the plurality of first and / or second electrodes, wherein the bias voltages define voltages for rows or columns connected to the electrodes, activate or deactivate imaging by individual imaging elements in the row or column, and define an angular imaging aperture. The method further includes applying a bias voltage to selected electrodes to activate or deactivate selected imaging elements and define an angular imaging aperture.

[0201] FIG. 25 illustrates a method for optimizing the angular imaging aperture 2500 of the present invention.

[0202] Aspects of the invention also provide a method for optimizing an imaging aperture, comprising: providing 2501 a controller operatively associated with an imaging device as described herein, the controller comprising: a transducer comprising an array of individual imaging elements arranged in rows longitudinally along the transducer and in columns transversely along the transducer, wherein signal connectivity of the individual imaging elements is defined by row and column addresses of the array; a plurality of first electrodes, each first electrode connecting with a row of individual imaging elements; and a plurality of second electrodes arranged at a non-zero angle relative to the plurality of first electrodes, each second electrode connecting with a column of individual imaging elements. Further, the controller is coupled to a non-transitory computer-readable memory comprising instructions executable by a processor to cause 2503 the controller to selectively apply bias voltage levels to one or more of the plurality of first electrodes and / or the plurality of second electrodes. Thus, the method includes applying bias voltage levels to one or more selected electrodes such that the applied bias voltage levels define voltages for rows or columns connected to the electrodes, activate or deactivate imaging by individual imaging elements in the row or column 2405, and define an angular imaging aperture 2507. The angular imaging aperture may then be optimized 2509.

[0203] As discussed above, the systems and methods of the present invention employ matrix addressing to adjust the imaging aperture. Instead of connecting each element individually, all rows and all columns are connected together, allowing elements to be addressed in a matrix manner. For example, front electrodes on the imaging array may address the columns (or "rings" on a cylindrical array), and back electrodes on the imaging array may address the "rows." Notably, the front and back electrodes of the imaging array may be switched for ring / row addressing, respectively.

[0204] Additionally, the present method provides for the use of bias voltages to adjust the frequency range of the imaging array, with the sensitivity for the frequency range being driven by the bias voltage. The bias voltage can be used to completely deactivate the imaging elements. Importantly, using bias voltages to activate imaging elements (i.e., cells) enables imaging without multiplexing. The present method provides for the use of matrix addressing on the back (or front) electrodes to control the bias voltages applied to the imaging elements and dynamically activate specific groups of elements or adjust their frequency range sensitivity.

[0205] The bias voltage may be applied based on the row address and / or column address of one or more of the individual imaging elements. For example, a bias voltage may be applied to activate imaging in one or more rows. Similarly, a bias voltage may be applied to activate imaging in one or more columns.

[0206] Further, the method may include adjusting a bias voltage to adjust the frequency of the imaging element. The bias voltages selectively applied to the plurality of first electrodes and the plurality of second electrodes may be the same or different for each electrode, allowing the frequency of the imaging element to be adjusted higher and / or lower to achieve a desired frequency.

[0207] A bias voltage of 0 V may be applied to deactivate a row, i.e., attenuating the element sensitivity to -60 dB. For example, applying a bias voltage of 0 V or a voltage level at which the sensitivity of the imaging element is minimal may deactivate imaging in a row or column. For example, one or more columns and / or one or more rows may be deactivated, or alternatively, all but one or more columns and / or one or more rows may be deactivated to selectively activate the apertures of the imaging elements.

[0208] To define the angular imaging aperture, the method of the present invention allows access to specific imaging elements as needed without performing fixed motion on subapertures. As noted above, using row and column addressing to define (i.e., adjust) the angular imaging aperture of an array applies to any convex array surface with a specific radius. This concept may also be applied to the special case of a convex surface around the entire imaging probe, i.e., a cylindrical surface. Thus, the angular imaging aperture may be understood to mean the angular direction along the curvature.

[0209] In the methods of the present invention, the angular imaging aperture may be defined as one or more rows or one or more columns of the imaging array based on the beam aperture sensitivity of the individual imaging elements of the array. Specifically, the imaging aperture may be defined by the number of rows (Nr) and / or the number of columns (Nc) to which a bias voltage is applied, and the number of interconnections between the imaging elements may be Nr + Nc.

[0210] For example, the angular imaging aperture may be defined as 1 row or 1 column to approximately 10 rows or 10 columns. The individual beam aperture sensitivities may be known so that they are included in the calculation of the desired angular imaging aperture. For example, the individual beam aperture sensitivities of the imaging elements may be obtained through measurements and / or simulations based on the geometric and acoustic properties of the ultrasound imaging sensor array.

[0211] The bias voltage may be applied to the front electrode or the back electrode. As an example, with Nr back electrodes, the electrodes may address rows for transmission and reception. In addition, the bias voltage may be adjustable to adjust the center frequency of the imaging element. The bias voltages selectively applied to the plurality of first electrodes and the plurality of second electrodes may be the same or different for each electrode, allowing the imaging frequency of the imaging element to be adjusted higher and / or lower to achieve a desired frequency.

[0212] For example, a bias voltage of 35V may be applied to the row as a nominal voltage (adjusted for 10 MHz imaging). Bias adjustment (up or down) may be used to adjust the center frequency. Nc front electrodes may address the columns / rings for transmission and reception. A transmit pulse may be sent and data may be received for all rings / columns in a selected row. This allows elements in a row to be addressed as a single element. Positive and / or negative bias voltage levels selectively applied to the multiple first electrodes and / or multiple second electrodes may adjust the imaging operation mode.

[0213] In some embodiments of the present method, the imaging device may include multiple interface modules, such that each interface module is operably connected to both the controller and one electrode connecting to a row or column. Further, for bias voltage selection, each row and column bias voltage may be individually enabled, disabled, or set using a digital-to-analog converter (DAC) specific to each imaging element. The DACs may be addressable via a common transmit (Tx) and voltage bias (Vbias) control serial bus.

[0214] In some embodiments, one or more bias voltage selection circuits are connected to the controller using one or more multipoint communication interfaces. In some embodiments, control of the transmit and / or receive functions uses one or more interfaces that are common to or separate from the interface used for bias voltage selection.

[0215] The controller may also include protection circuitry operatively connected in series with each row and column of individual imaging elements so that multiple bias voltage levels cannot be applied to a given electrode simultaneously. For example, the protection circuitry may be a fuse or a circuit breaker or other circuit protection device. In some embodiments, the ORing circuitry utilizes diodes and / or transistors.

[0216] One or more ORing diodes may be placed in series with each DAC output to protect each element from simultaneous activation of the bias voltages at its row and column address locations. In this example, the ORing diodes are in series with the DACs to protect the element at address (i,j) from simultaneous activation of Vbias_i and Vbias_j. For non-CMUT elements, the DACs may be disabled to achieve Vbias_i = Vbias_j = 0V or Hz.

[0217] The controller may be configured to activate single or multiple rows at a time using the same or different bias voltage levels to achieve the intended angular imaging aperture. In some embodiments, the controller may be configured to activate single or multiple columns at a time using the same or different bias voltage levels to achieve the intended angular imaging aperture. The controller may be configured to activate multiple individual imaging elements simultaneously based on the row and column address locations of the individual individual imaging elements. Thus, simultaneously activated individual imaging elements may have the same or different bias voltage levels.

[0218] For example, in embodiments, bias voltages selectively applied to one or more of the plurality of first electrodes and / or the plurality of second electrodes enable or disable transmit and / or receive functions and define transmit / receive events, such that each transmit / receive event comprises an activation and / or adjustment scheme. Thus, the controller is configured to control the activation and / or adjustment scheme individually for each transmit / receive event, such that multiple transmit / receive events can have the same or alternating activation and / or adjustment schemes.

[0219] The controller may include a computer program comprising an algorithm for evaluating, calculating, and optimizing the angular imaging aperture. For example, using the defined algorithm, the controller may be configured to provide feedback to an operator before or during operation of the imaging array to evaluate, calculate, and optimize the angular imaging aperture. The controller may also be configured to provide feedback after operation of the imaging array. The algorithm 201 may be part of a computer program executable by the computing system 203 and in communication with the controller of the imaging device.

[0220] In this embodiment, the controller may be configured to activate single or multiple rows at a time using the same or different bias voltage levels to achieve an optimized angular imaging aperture. The controller may be configured to activate single or multiple columns at a time using the same or different bias voltage levels to achieve an optimized angular imaging aperture.

[0221] To activate a desired row of the imaging element, the controller may select a transmission address corresponding to the desired row and send a signal with a desired bias voltage level to the interface for the desired row. Similarly, to activate a desired column of the imaging element, the controller may select a transmission address corresponding to the desired column and send a signal with a desired voltage level for the desired column to the interface.

[0222] A bias voltage applied to the first electrode may activate imaging elements connected to the second electrode for both transmit and receive functions. Transmission to only the desired row of elements may be achieved by selecting a transmit address on the Tx and Vbias control bus to activate all elements in a row. For example, to activate all elements in row i, a transmit address corresponding to row i on the Tx and Vbias control bus may be selected. This enables and sets the value of the row bias voltage. For row i, the bias voltage is designated as Vbias_i. Thus, the value of the row i bias voltage (Vbias_i) may be enabled and set. Furthermore, the column bias voltage for column j, designated as Vbias_j, may be disabled by setting Vbias_j equal to 0V or Hz for all columns. Notably, multiple rows may be activated simultaneously using the same or different bias voltage levels. In this manner, an imaging aperture for ultrafast imaging may be defined.

[0223] A bias voltage applied to the first electrode may activate (i) the receive function of each imaging element connected to the first electrode and the transmit function of each imaging element connected to the second electrode, or (ii) the transmit function of each imaging element connected to the first electrode and the receive function of each imaging element connected to the second electrode.

[0224] A bias voltage applied to the second electrode may activate (i) the receive function of each imaging element connected to the second electrode and the transmit function of each imaging element connected to the first electrode, or (ii) the transmit function of each imaging element connected to the second electrode and the receive function of each imaging element connected to the first electrode.

[0225] A bias voltage applied to the first electrode may activate the transmit or receive functions of the individual imaging elements connected to the first electrode and the transmit or receive functions of the individual imaging elements connected to the second electrode.

[0226] A bias voltage applied to the first electrode may activate the transmit or receive functions of the individual imaging elements connected to the first electrode and the transmit or receive functions of the individual imaging elements connected to the second electrode.

[0227] The present method provides a flexible arrangement of the controller and associated components, flexibly accommodating various size embodiments of the device design to suit a particular application. For example, the controller's integrated circuit may be housed with the analog front-end circuitry at the catheter tip adjacent to the imaging element. The integrated circuit may be housed with the analog front-end circuitry operably coupled to and positioned directly adjacent to the imaging element. The signal generator, signal transmitter, and / or switching circuitry are housed in a remote enclosure connected to the imaging element via circuitry. The circuitry may include, for example, a cable assembly, a printed circuit, and / or one or more flexible printed circuits.

[0228] The device of the method may provide a plurality of first electrodes connecting with rows of individual imaging elements, and a plurality of second electrodes arranged at a non-zero angle relative to the plurality of first electrodes.

[0229] The plurality of second electrodes may be arranged orthogonally relative to the plurality of first electrodes. For example, the transmit and receive functions may be on the same electrode, with activation of individual elements through bias (on / off) on the orthogonal electrode. This, in combination with the orthogonal electrodes, allows for addressing of individual elements by bias voltage. Note that the transmit and receive functions may be on the same electrode or on orthogonal electrodes.

[0230] Additionally, the second set of electrodes may not be orthogonal to the first set of electrodes, but instead may be at any non-zero angle relative to the first set of electrodes. Furthermore, the front and / or back electrodes may be switched in terms of interconnection (bias injection vs. AC signal for transmission function).

[0231] The controller may include an integrated circuit housed in an enclosure with the imaging element or positioned on a substrate with the imaging element. For example, the substrate may be a flexible substrate such as a polymer substrate, a compliant silicone elastomer, or other material capable of housing both the integrated circuitry and the imaging element, as known to those skilled in the art. In this embodiment, the controller may also include an analog front-end circuit housed separately from the imaging element, and may include one or more signal generators and / or one or more signal transmitters, and / or one or more switching circuits. For example, the analog front-end circuit (i.e., a set of analog conditioning circuitry using high-sensitivity analog amplifiers) may use operational amplifiers, filters, or ASICs for sensors or other circuits to interface with the sensors, analog-to-digital converters (ADCs), or microcontrollers.

[0232] Alternatively, in some embodiments, the controller may be stored separately from the imaging element and operably coupled to the imaging element via circuitry. For example, the circuitry may include at least one of one or more cable assemblies, one or more printed circuits, and / or one or more flexible printed circuits. Furthermore, the controller may include analog front-end circuitry stored separately from the imaging element, including an ultrasound signal generator and transmitter, an ultrasound signal amplifier and receiver, and switching circuitry, which may be packaged separately from the imaging element or may be packaged in a remote enclosure connected to the imaging element via a cable assembly.

[0233] The device of this method may have more than one controller. For example, in addition to the controller that selectively controls the bias voltage, there may be a second (or the same) controller that transmits ultrasound pulses at a certain imaging frequency into tissue and then converts the received echoes into digital signals. This may be understood as an ultrasound analog front end that provides transmit and receive capabilities, which may be integrated with bias activation or implemented separately. The transmit and receive functions of the ultrasound transmit and receive sequences may be controlled in synchronization with the controller for bias adjustment and selection, enabling intelligent beamforming.

[0234] The transducer of the present method may be a microelectromechanical system (MEMS)-based capacitive micromachined ultrasonic transducer (CMUT) configured in a two-dimensional (2D) array structure. In a non-limiting example, the 2D array may be a flexible structure. The device of the present method may include a cylindrical imaging array, which in a CMUT design may consist of a flexible 2D array structure. The transducer may be made of an electrostrictive material configured in the two-dimensional (2D) array structure, or different MEMS-based transducers may be configured in the two-dimensional (2D) array structure.

[0235] The transducers may be made from electrostrictive materials arranged in a two-dimensional (2D) array structure.

[0236] The multiple imaging elements may be acoustic sensors selectively activated by a controller based on row and / or column addresses of the acoustic sensors to transmit and / or receive multiple incident acoustic wave signals as wave data. The wave data may be, for example, at least one of plane wave data and diverging wave data associated with one or more plane wave transmit / receive cycles performed by the imaging elements. The active elements used for transmission and reception may comprise all elements in both transmission and reception, the same subset of elements used for transmission and reception, or different subsets (or complete sets) of elements used for transmission and reception of wave data.

[0237] The wave data may be full-circumference three-dimensional (3D) image data. For example, using matrix addressing in conjunction with bias activation, an array of acoustic sensors may be set to different transmit angular positions, thus transmitting multiple incident acoustic wave signals representing one or more plane waves of a group of plane waves, to help depict a 3D image over time.

[0238] For a cylindrically shaped transducer, an array of individual imaging elements may be arranged in rows longitudinally along the transducer and in columns circumferentially around the transducer. The imaging array may include a number of rows (Nr), a number of individual imaging elements per row (Ne), a row spacing, and a number of columns (Nc), such that the total number of imaging elements in the array is (Ne·Nr), and the individual imaging elements may be connected through a number of connections represented by Nr+Nc. Thus, in some embodiments, Nr connections are used to transmit and receive ultrasound signals as ultrafast wave data, and Nc connections are used to control bias voltages to the elements.

[0239] A cylindrical transducer may have thousands of elements, enabling ultrafast plane wave imaging. For example, with 64 rows (rings) and 1 degree angular spacing, this would result in 23,040 elements. Similarly, in one embodiment, a cylindrical transducer may have 128 elements per row and 1 degree row spacing, resulting in 46,080 individual imaging elements. These elements may be connected through 488 connections (128 + 360), with 360 lines used to control bias voltages and 128 lines used to transmit and receive ultrasound signals as ultrafast wave data.

[0240] The row spacing around the cylindrical array can be any planar angle, for example, the row spacing can be from about 0.1 degrees to about 5 degrees in the angular direction.

[0241] A bias voltage may be applied to the first electrode and connected to the second electrode to activate transmit and / or receive functionality on the individual imaging elements such that the individual imaging elements transmit and / or receive ultrasound signals in the form of ultrafast wave data. In certain embodiments, the transducer array may include a number (N) of individual imaging elements per row in an array design that enables ultrafast plane wave and / or diverging wave imaging, where the plane wave and / or diverging wave imaging modes capture reflected signal data at a rate of at least 10 kHz.

[0242] As used in any embodiment herein, the term “module” may refer to software, firmware, and / or circuitry configured to perform any of the operations described above. Software may be embodied as a software package, code, instructions, an instruction set, and / or data recorded on a non-transitory computer-readable storage medium. Firmware may be embodied as hard-coded (e.g., non-volatile) code, instructions, or an instruction set, and / or data in a memory device. “Circuitry,” as used in any embodiment herein, may comprise, for example, wired circuitry, programmable circuitry such as a computer processor with one or more individual instruction processing cores, state machine circuitry, and / or firmware that stores instructions executed by the programmable circuitry, either alone or in any combination. Modules may collectively or individually be embodied as circuitry that forms part of a larger system, for example, an integrated circuit (IC), a system-on-chip (SoC), a desktop computer, a laptop computer, a tablet computer, a server, a smartphone, etc.

[0243] Any of the operations described herein may be implemented in a system that includes one or more storage media having instructions stored thereon, individually or in combination, that, when executed by one or more processors, perform the method, where the processors may include, for example, a server CPU, a mobile device CPU, and / or other programmable circuitry.

[0244] It is also contemplated that the operations described herein may be distributed across multiple physical devices, such as processing structures, in more than one different physical location. The storage medium may include, for example, any type of disk, including hard disks, floppy disks, optical disks, compact disk-read-only memories (CD-ROMs), rewritable compact disks (CD-RWs), and magneto-optical disks; semiconductor devices, such as read-only memories (ROMs); random access memories (RAMs), such as dynamic and static RAMs; erasable programmable read-only memories (EPROMs); electrically erasable programmable read-only memories (EEPROMs); flash memory; solid-state disks (SSDs); magnetic or optical cards; or any type of tangible medium suitable for storing electronic instructions. Other embodiments may be implemented as software modules executed by a programmable control device. The storage medium may be non-transitory.

[0245] As described herein, various embodiments may be implemented using hardware elements, software elements, or any combination thereof. Examples of hardware elements may include processors, microprocessors, circuits, circuit elements (e.g., transistors, resistors, capacitors, inductors, etc.), integrated circuits, application specific integrated circuits (ASICs), programmable logic devices (PLDs), digital signal processors (DSPs), field programmable gate arrays (FPGAs), logic gates, registers, semiconductor devices, chips, microchips, chipsets, etc.

[0246] References throughout this specification to "one embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification do not necessarily all refer to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0247] The term "non-transitory" should be understood to exclude only propagating, ephemeral signals per se from the scope of the claims, and does not disclaim all standard computer-readable media other than propagating, ephemeral signals per se. In other words, the terms "non-transitory computer-readable medium" and "non-transitory computer-readable storage medium" should be interpreted to exclude only those types of ephemeral computer-readable media that In Re Nuijten found to fall outside the scope of patentable subject matter under 35 U.S.C. § 101.

[0248] The terms and expressions employed herein are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions to exclude any equivalents of the features (or portions thereof) shown and described, recognizing that various modifications are possible within the scope of the claims. The claims are therefore intended to cover all such equivalents. Incorporation by Reference

[0249] References and citations to other documents, such as patents, patent applications, patent publications, journals, books, papers, web content, etc. are made throughout this disclosure. All such documents are incorporated herein by reference in their entirety for all purposes. equivalent

[0250] Various modifications of the invention and many further embodiments thereof, in addition to those shown and described herein, will become apparent to those skilled in the art from the complete contents of this document, including by reference to the scientific and patent literature cited herein. The subject matter of this specification contains important information, exemplification, and guidance that can be adapted to the practice of this invention in its various embodiments and equivalents thereof.

Claims

1. 1. A system for optimizing an imaging aperture, comprising: a controller operatively associated with an imaging device, the imaging device comprising: a transducer comprising an array of individual imaging elements arranged in rows lengthwise along the transducer and in columns widthwise along the cylindrical transducer, the signal connectivity of the individual imaging elements being defined by row and column address locations of the array; a plurality of first electrodes, each of the plurality of first electrodes connecting with a respective row of imaging elements; a plurality of second electrodes arranged at a non-zero angle relative to the plurality of first electrodes, each of the plurality of second electrodes connecting to a respective column of imaging elements; Equipped with The controller is coupled to a non-transitory computer-readable memory including instructions executable by the processor to cause the controller to selectively apply bias voltage levels to one or more of the plurality of first electrodes and / or the plurality of second electrodes, the bias voltage levels defining voltages for the rows or columns connected to the electrodes, activating or deactivating imaging by the individual imaging elements in the rows or columns, and defining an angular imaging aperture.

2. 2. The system of claim 1, wherein the angular imaging aperture is defined by a number of rows (Nr) and / or columns (Nc) to which the bias voltage is applied, and the number of interconnections between imaging elements is Nr+Nc.

3. The system of claim 1 , further comprising a plurality of interface modules, each interface module operatively connected to both the controller and one electrode connecting to a row or column.

4. 4. The system of claim 3, wherein bias voltage levels for each row and / or column are individually enabled, disabled, and set using the interface module for the row or the column.

5. 4. The system of claim 3, wherein to activate a desired row of imaging elements, the controller selects a transmission address corresponding to the desired row and sends a signal with a desired bias voltage level to the interface for the desired row.

6. 4. The system of claim 3, wherein to activate a desired column of imaging elements, the controller selects a transmission address corresponding to the desired column and sends a signal to the interface at a desired voltage level for the desired column.

7. 4. The system of claim 3, wherein the interface further comprises one or more ORing circuits in series with digital-to-analog converter (DAC) outputs to protect each imaging element from simultaneous activation of bias voltages at its row and column address locations.

8. The system of claim 7 , wherein the ORing circuit utilizes a diode and / or a transistor.

9. The system of claim 1 , wherein the controller further comprises a computer program comprising an algorithm for evaluating, calculating, and optimizing the angular imaging aperture.

10. 10. The system of claim 9, wherein the controller is configured to activate single or multiple rows at a time using the same or different bias voltage levels to achieve the optimized angular imaging aperture.

11. 10. The system of claim 9, wherein the controller is configured to activate single or multiple columns at a time using the same or different bias voltage levels to achieve the optimized angular imaging aperture.

12. The system of claim 1 , wherein the controller is configured to activate single or multiple rows at a time using the same or different bias voltage levels to achieve an intended angular imaging aperture.

13. The system of claim 1 , wherein the controller is configured to activate single or multiple columns at a time using the same or different bias voltage levels to achieve an intended angular imaging aperture.

14. The system of claim 1 , wherein the controller activates multiple individual imaging elements simultaneously based on the row address location and the column address location of the individual imaging elements.

15. The system of claim 14 , wherein the simultaneously activated individual imaging elements have the same or different bias voltage levels.

16. 10. The system of claim 1, wherein bias voltages selectively applied to one or more of the plurality of first electrodes and / or the plurality of second electrodes enable or disable transmit and / or receive functions and define transmit / receive events, each transmit / receive event comprising an activation and / or coordination scheme.

17. 17. The system of claim 16, wherein the controller is configured to control the activation and / or coordination scheme for each transmit / receive event individually, such that multiple transmit / receive events can have the same or alternating activation and / or coordination schemes.

18. 10. The system of claim 1, wherein the controller comprises protection circuitry operatively connected in series with each row and each column of individual imaging elements so that multiple bias voltage levels cannot be applied to a given electrode simultaneously.

19. The system of claim 1 , wherein the controller comprises an integrated circuit housed in an enclosure with the imaging element or located on a substrate with the imaging element.

20. The system of claim 1 , wherein the controller is housed separately from the imaging element and operably coupled to the imaging element via circuitry.

21. 21. The system of claim 20, wherein the circuitry comprises at least one of one or more cable assemblies, one or more printed circuits, and / or one or more flexible printed circuits.

22. The controller further comprises: an integrated circuit for bias voltage generation and control, said integrated circuit housed in an enclosure with said imaging element or located on a substrate with said imaging element; an analog front-end circuit housed separately from the imaging element and including one or more signal generators and / or one or more signal transmitters and one or more switching circuits; The system of claim 1 , comprising:

23. 23. The system of claim 22, wherein the integrated circuit, along with the analog front-end circuitry, is housed in a catheter tip adjacent the imaging element.

24. 23. The system of claim 22, wherein the integrated circuit is housed with the analog front-end circuitry operably coupled to and located directly adjacent to the imaging element.

25. 23. The system of claim 22, wherein at least one of the one or more switching circuits, the one or more signal transmitters, and the one or more switching circuits are housed in a remote enclosure connected to the imaging element via circuitry comprising one or more cable assemblies, one or more printed circuits, and / or one or more flexible printed circuits.

26. The system of claim 1 , wherein the bias voltage level is adjustable to adjust the frequency of the imaging element.

27. 27. The system of claim 26, wherein the bias voltage levels selectively applied to the plurality of first electrodes and the plurality of second electrodes may be the same or different for each electrode, allowing the imaging frequency of the imaging element to be adjusted higher and / or lower to achieve a desired frequency.

28. 27. The system of claim 26, wherein positive and / or negative bias voltage levels selectively applied to the plurality of first electrodes and / or the plurality of second electrodes adjust an imaging mode of operation.

29. The system of claim 1 , wherein applying a bias voltage of 0V or a voltage level to which the imaging element is minimally sensitive deactivates imaging in the row or column.

30. 30. The system of claim 29, wherein one or more columns and / or one or more rows are deactivated.

31. The system of claim 1 , wherein the angular imaging aperture is one or more rows or columns defined based on the beam aperture sensitivity of individual imaging elements of the array.

32. 32. The system of claim 31, wherein the angular imaging aperture is defined as 1 row or 1 column to about 10 rows or columns.

33. 10. The system of claim 1, wherein the transducers are micro-electromechanical systems (MEMS)-based capacitive micro-machined ultrasonic transducers (CMUTs) configured as a two-dimensional (2D) array structure.

34. 34. The system of claim 33, wherein the 2D array structure is a flexible structure.

35. The system of claim 1 , wherein the transducer comprises an electrostrictive material configured in a two-dimensional (2D) array structure.

36. 2. The system of claim 1, wherein the plurality of imaging elements are acoustic sensors that receive a plurality of incident acoustic wave signals as wave data and are selectively activated by the controller based on the row address and / or the column address of the acoustic sensor.

37. 37. The system of claim 36, wherein the wave data comprises at least one of plane wave data and / or diverging wave data associated with one or more plane wave transmit / receive cycles performed by the imaging element.

38. 37. The system of claim 36, wherein the wave data is full-circumference three-dimensional (3D) image data.

39. The system of claim 1 , wherein the transducer is cylindrically shaped.

40. 40. The system of claim 39, wherein the array of individual imaging elements is arranged in rows longitudinally along the transducer and in columns circumferentially around the transducer.

41. 40. The system of claim 39, wherein the array comprises a number of rows (Nr), a number of individual imaging elements per row (Ne), a row spacing, and a number of columns (Nc), wherein the total number of imaging elements in the array is (Ne·Nr), and the individual imaging elements are connected through a number of connections represented by Nr+Nc.

42. 40. The system of claim 39, wherein the row spacing is between about 0.1 degrees and about 1 degree in an angular orientation.

43. 40. The system of claim 39, wherein the bias voltage is applied to a first electrode to activate a transmit and / or receive function on the individual imaging elements connected to the second electrode such that the individual imaging elements transmit and / or receive ultrasound signals in the form of ultrafast wave data.

44. 44. The system of claim 43, wherein the transducer array comprises a number of individual imaging elements (Ne) per row in an array design that enables ultrafast plane wave and / or diverging wave imaging, and wherein the plane wave and / or diverging wave imaging mode includes capturing plane wave reflected signal data at a rate of at least 10 kHz.

45. The system of claim 1 , wherein the plurality of second electrodes are arranged orthogonally to the plurality of first electrodes.

46. The system of claim 1 , wherein one or more bias voltage selection circuits are connected to the controller using one or more multipoint communication interfaces.

47. The system of claim 1 , wherein the control of the transmit and / or receive functions uses one or more interfaces that are common to or separate from an interface used for bias voltage selection.

48. 1. A method for optimizing an imaging aperture, comprising: A controller operatively associated with an imaging device, the imaging device comprising: a transducer comprising an array of individual imaging elements arranged in a plurality of rows vertically along the transducer and a plurality of columns horizontally along the transducer, signal connectivity of the individual imaging elements being defined by row and column address locations of the array; a plurality of first electrodes, each of the plurality of first electrodes connecting with a respective row of imaging elements; a plurality of second electrodes arranged at a non-zero angle relative to the plurality of first electrodes, each of the plurality of second electrodes connecting to a respective column of imaging elements; the controller is coupled to a non-transitory computer-readable memory comprising instructions executable by the processor to cause the controller to selectively apply bias voltage levels to one or more of the plurality of first electrodes and / or the plurality of second electrodes; applying a bias voltage level to one or more selected electrodes, the applied bias voltage level defining a voltage for the row or column connected to the electrode, activating or deactivating imaging by the individual imaging elements in the row or column, and defining an angular imaging aperture; A method comprising:

49. 49. The method of claim 48, wherein the angular imaging aperture is defined by the number of rows (Nr) and / or columns (Nc) to which the bias voltage is applied, and the number of interconnects between individual imaging elements is Nr + Nc.

50. 49. The method of claim 48, wherein the imaging device further comprises a plurality of interface modules, each interface module operatively connected to both the controller and to one electrode connecting with a row or column.

51. 51. The method of claim 50, wherein bias voltage levels for a selected row and / or a selected column are individually enabled, disabled, and set using the interface module for the row or the column.

52. 51. The method of claim 50, wherein to activate a desired row of imaging elements, the controller selects a transmission address corresponding to the desired row and sends a signal with a desired bias voltage level to the interface for the desired row.

53. 51. The method of claim 50, wherein to activate a desired column of imaging elements, the controller selects a transmission address corresponding to the desired column and sends a signal to the interface at a desired voltage level for the desired column.

54. 51. The method of claim 50, wherein the interface further comprises one or more ORing circuits in series with digital-to-analog converter (DAC) outputs to protect each imaging element from simultaneous activation of bias voltages at its row and column address locations.

55. 55. The method of claim 54, wherein the ORing circuit utilizes a diode and / or a transistor.

56. 49. The method of claim 48, wherein the controller further comprises a computer program comprising an algorithm for evaluating, calculating, and optimizing the angular imaging aperture.

57. 57. The method of claim 56, wherein the controller is configured to activate single or multiple rows at a time using the same or different bias voltage levels to achieve the optimized angular imaging aperture.

58. 57. The method of claim 56, wherein the controller is configured to activate single or multiple columns at a time using the same or different bias voltage levels to achieve the optimized angular imaging aperture.

59. 49. The method of claim 48, wherein the controller is configured to activate single or multiple rows at a time using the same or different bias voltage levels to achieve the intended angular imaging aperture.

60. 49. The method of claim 48, wherein the controller is configured to activate single or multiple columns at a time using the same or different bias voltage levels to achieve the intended angular imaging aperture.

61. 49. The method of claim 48, wherein the controller activates multiple individual imaging elements simultaneously based on the row address location and the column address location of the respective individual imaging elements.

62. 62. The method of claim 61, wherein the simultaneously activated individual imaging elements have the same or different bias voltage levels.

63. 49. The method of claim 48, wherein bias voltages selectively applied to one or more of the plurality of first electrodes and / or the plurality of second electrodes enable or disable transmit and / or receive functions and define transmit / receive events, each transmit / receive event comprising an activation and / or adjustment scheme.

64. 64. The method of claim 63, wherein the controller is configured to control the activation and / or coordination scheme for each transmit / receive event individually, such that multiple transmit / receive events may have the same or alternating activation and / or coordination schemes.

65. 49. The method of claim 48, wherein the controller comprises protection circuitry operatively connected in series with each row and each column of individual imaging elements so that multiple bias voltage levels cannot be applied to a given electrode simultaneously.

66. 49. The method of claim 48, wherein the controller comprises an integrated circuit housed in an enclosure with the imaging element or located on a substrate with the imaging element.

67. 49. The method of claim 48, wherein the controller is stored separately from the imaging element and operably coupled to the imaging element via circuitry.

68. 68. The method of claim 67, wherein the circuitry comprises at least one of one or more cable assemblies, one or more printed circuits, and / or one or more flexible printed circuits.

69. The controller further comprises: an integrated circuit for bias voltage generation and control, said integrated circuit housed in an enclosure with said imaging element or located on a substrate with said imaging element; an analog front-end circuit housed separately from the imaging element and including one or more signal generators and / or one or more signal transmitters and one or more switching circuits; 49. The method of claim 48, comprising:

70. 70. The method of claim 69, wherein the integrated circuit, along with the analog front-end circuitry, is housed in a catheter tip adjacent to the imaging element.

71. 70. The method of claim 69, wherein the integrated circuit is housed with the analog front-end circuitry operably coupled to and located immediately adjacent to the imaging element.

72. 70. The method of claim 69, wherein at least one of the one or more switching circuits, the one or more signal transmitters, and the one or more switching circuits are housed in a remote enclosure connected to the imaging element via circuitry comprising one or more cable assemblies, one or more printed circuits, and / or one or more flexible printed circuits.

73. 49. The method of claim 48, further comprising adjusting the bias voltage level to tune the frequency of the imaging element.

74. 74. The method of claim 73, wherein the bias voltage levels selectively applied to the plurality of first electrodes and the plurality of second electrodes are the same or different for each electrode, allowing the imaging frequency of the imaging element to be adjusted higher and / or lower to achieve a desired frequency.

75. 74. The method of claim 73, wherein positive and / or negative bias voltage levels selectively applied to the plurality of first electrodes and / or the plurality of second electrodes adjust an imaging mode of operation.

76. 49. The method of claim 48, wherein applying a bias voltage of 0V or a voltage level to which the imaging element is minimally sensitive deactivates imaging in the row or column.

77. 77. The method of claim 76, wherein one or more columns and / or one or more rows are deactivated.

78. 49. The method of claim 48, wherein the angular imaging aperture is one or more rows or columns defined based on the beam aperture sensitivity of individual imaging elements of the array.

79. 79. The method of claim 78, wherein the angular imaging aperture is defined as 1 row or 1 column to about 10 rows or columns.

80. 49. The method of claim 48, wherein the transducers are micro-electromechanical systems (MEMS)-based capacitive micro-machined ultrasonic transducers (CMUTs) configured in a two-dimensional array structure.

81. 81. The method of claim 80, wherein the two-dimensional array structure is a flexible structure.

82. 49. The method of claim 48, wherein the transducer comprises an electrostrictive material configured in a two-dimensional array structure.

83. 49. The method of claim 48, wherein the plurality of imaging elements are acoustic sensors that receive a plurality of incident acoustic wave signals as wave data and are selectively activated by the controller based on the row address and / or the column address of the acoustic sensor.

84. 84. The method of claim 83, wherein the wave data comprises at least one of plane wave data and / or diverging wave data associated with one or more plane wave transmit / receive cycles performed by the imaging element.

85. 84. The method of claim 83, wherein the wave data is full-circumference three-dimensional (3D) image data.

86. 49. The method of claim 48, wherein the transducer is cylindrically shaped.

87. 87. The method of claim 86, wherein the array of individual imaging elements is arranged in a plurality of rows longitudinally along the transducer and in a plurality of columns circumferentially around the transducer.

88. 87. The method of claim 86, wherein the array comprises a number of rows (Nr), a number of individual imaging elements per row (Ne), a row spacing, and a number of columns (Nc), wherein the total number of imaging elements in the array is (Ne·Nr), and the individual imaging elements are connected through a number of connections represented by Nr+Nc.

89. 87. The method of claim 86, wherein the row spacing is between about 0.1 degrees and about 1 degree in an angular direction.

90. 87. The method of claim 86, wherein the bias voltage is applied to a first electrode to activate a transmit and / or receive function on the individual imaging elements connected to the second electrode such that the individual imaging elements transmit and / or receive ultrasound signals in the form of ultrafast wave data.

91. 91. The method of claim 90, wherein the transducer array comprises a number of individual imaging elements (Ne) per row in an array design that enables ultrafast plane wave and / or diverging wave imaging, and the plane wave and / or diverging wave imaging mode includes capturing plane wave reflected signal data at a rate of at least 10 kHz.

92. 49. The method of claim 48, wherein the plurality of second electrodes are arranged orthogonal to the plurality of first electrodes.

93. 49. The method of claim 48, wherein one or more bias voltage selection circuits are connected to the controller using one or more multipoint communication interfaces.

94. 49. The method of claim 48, wherein the control of the transmit and / or receive functions uses one or more interfaces that are common to or separate from an interface used for bias voltage selection.

Images