Medical imaging devices

Abstract

A medical imaging device is disclosed. The medical imaging device includes an ultrasonic transducer having an acoustic stack including an active surface opposite to the backing surface, a magnetic tracking sensor assembly, and a multilayer circuit assembly electrically and mechanically coupled to the ultrasonic transducer and the magnetic tracking sensor assembly. The magnetic tracking sensor assembly includes a coupling surface. The backing surface is aligned with the coupling surface.

Description

Technical Field

[0001] The present disclosure relates to medical systems and methods for enabling visualization of tissue within a patient. More specifically, the present disclosure relates to a medical system, a catheter, and a method having an ultrasonic transducer device.

Background Art

[0002] Intracardiac echocardiography (ICE) is an ultrasonic imaging modality that is a common element of a plurality of percutaneous interventions and electrophysiological procedures. ICE can provide high-resolution and real-time visualization of cardiac structures, continuous monitoring of catheter positions within the heart, and early recognition of treatment complications such as pericardial fluid retention or thrombosis. The ICE catheter is inserted into a vein or artery, for example, via a standard femoral venous introducer into the femoral vein, and then advanced from the vein or artery to the heart in parallel with other tools without using fluoroscopy. Another common ultrasonic imaging modality includes transesophageal echocardiography (TEE) and fluoroscopy for imaging and visualizing tools within the heart, which requires an anesthesiologist and an additional echocardiographer to place the patient under general anesthesia and manipulate an ultrasonic probe within the airway. In contrast to TEE, ICE is performed under conscious sedation by the primary operator of the interventional procedure, without the need for endotracheal intubation, thereby reducing the risk of esophageal trauma. Furthermore, ICE reduces the exposure of both the patient and the operator to fluoroscopy. For these reasons, ICE has the potential to replace TEE as a preferred imaging modality in certain procedures such as atrial septal defect closure and catheter ablation of cardiac arrhythmias, and also has a new role in other procedures such as mitral valvuloplasty, transcatheter aortic valve replacement, and left atrial appendage closure.

[0003] Two forms of ICE are available. Radial or rotational ICE uses a single piezoelectric crystal attached to the tip of a 2-3.3 mm (6-10 French) catheter. The rotational transducer provides a cross-sectional image in a radial plane perpendicular to the longitudinal axis of the catheter. Rotational ICE operates at imaging frequencies useful for short-range imaging up to 6 or 8 centimeters, but is limited for long-range imaging. Phased-array ICE uses a multi-element transducer, such as a 64-element transducer, which is attached to the distal end of a maneuverable 2.7-3.3 mm (8-10 French) catheter and can often be deflected in four directions, including anterior, posterior, right, and left. This device can acquire wedge-shaped images, such as a 90-degree sector plane, from the side of the catheter and display them on a conventional ultrasound workstation. Compared to mechanical rotary ICE systems, phased array ICEs can offer greater image depth (up to 15 cm), improved maneuverability, and the ability to acquire Doppler and color flow imaging. [Overview of the Initiative]

[0004] In Example 1, the medical imaging device comprises an ultrasonic transducer having an acoustic stack including an active surface opposite to the backing surface, a magnetic tracking sensor assembly, and a multilayer circuit assembly electrically and mechanically coupled to the ultrasonic transducer and the magnetic tracking sensor assembly, wherein the magnetic tracking sensor assembly has a coupling surface, and the backing surface is aligned with the coupling surface.

[0005] In Example 2, the multilayer circuit assembly in the medical imaging device of Example 1 includes a flexible circuit. In Example 3, in a medical imaging device according to any of Examples 1 or 2, the flexible circuit is substantially planar and includes a first portion and a second portion, the magnetic tracking sensor assembly and the ultrasonic transducer are electrically coupled to the first portion, and the second portion is folded below the first portion.

[0006] In Example 4, the magnetic tracking sensor assembly is located within a sealing material in any of the medical imaging devices of Examples 1 to 3. In Example 5, the sealing material is epoxy in the medical imaging device of Example 4.

[0007] In Example 6, in any of the medical imaging devices of Examples 1 to 5, the magnetic tracking sensor assembly includes one of a plurality of tunnel magnetoresistive sensors and a plurality of inductive sensors.

[0008] In Example 7, in any of the medical imaging devices of Examples 1 to 6, the ultrasonic transducer includes a matching layer, and the matching layer includes the active surface.

[0009] In Example 8, in any of the medical imaging devices of Examples 1 to 7, the ultrasonic transducer includes a backing layer, the backing layer has a backing surface, and the backing surface includes a plurality of grooves in the backing layer.

[0010] In Example 9, the medical imaging device of any of Examples 1 to 8 includes a phased array transducer. In Example 10, in any of the medical imaging devices of Examples 1 to 9, the medical imaging device is included in a distal cover attached to a catheter shaft.

[0011] In Example 11, the catheter is included in an imaging system that further includes a plurality of magnetic field transmitting assemblies, in the medical imaging device of Example 10. In Example 12, the medical imaging device of Example 11 further includes a controller operably coupled to the medical imaging device, the controller being configured to receive a detection signal from the ultrasonic transducer and a tracking signal from the magnetic tracking sensor assembly, and to generate an image including the position and orientation of a two-dimensional imaging plane in three-dimensional space.

[0012] In Example 13, in the medical imaging device of Example 1, the magnetic tracking assembly is attached to the multilayer circuit assembly via a wire bonding process.

[0013] In Example 14, in the medical imaging device of Example 12, the multilayer circuit assembly is folded into a stack, and the stack is placed on the magnetic tracking assembly.

[0014] In Example 15, in any of the medical imaging devices of Examples 1 to 14, the ultrasonic transducer is configured as a two-dimensional imaging phased array assembly including a one-dimensional device.

[0015] In Example 16, the medical imaging device comprises an ultrasonic transducer having an acoustic stack including an active surface opposite to the backing surface; a magnetic tracking sensor assembly; and a multilayer circuit assembly electrically and mechanically coupled to the ultrasonic transducer and the magnetic tracking sensor assembly, wherein the magnetic tracking sensor assembly has a coupling surface, and the backing surface is aligned with the coupling surface.

[0016] In Example 17, the multilayer circuit assembly in the medical imaging device of Example 16 includes a flexible circuit. In Example 18, in the medical imaging device of Example 17, the flexible circuit includes a first portion coupled to a folded stack, the magnetic tracking sensor assembly and the ultrasonic transducer are electrically coupled to the first portion, and the folded stack is folded below the first portion.

[0017] In Example 19, the medical imaging device of Example 18 includes a set of longitudinally extending conductive elements arranged between a plurality of longitudinally extending perforations.

[0018] In Example 20, in the medical imaging device of Example 18, each of the ultrasonic transducer and the magnetic tracking sensor assembly includes a plurality of electrical connections electrically coupled to a plurality of conductive elements extending in the longitudinal direction.

[0019] In Example 21, the magnetic tracking sensor assembly is located within the sealing material in the medical imaging device of Example 16. In Example 22, the sealing material is epoxy in the medical imaging device of Example 21.

[0020] In Example 23, the medical imaging device of Example 16 includes one of a plurality of tunnel magnetoresistive sensors and a plurality of inductive sensors.

[0021] In Example 24, the medical imaging device of Example 23 includes longitudinal portions that are angled toward each other. In Example 25, in the medical imaging device of Example 23, the magnetic tracking sensor assembly includes the plurality of tunnel magnetoresistance sensors electrically coupled to the plurality of corresponding sensor circuits.

[0022] In Example 26, in the medical imaging device of Example 16, the ultrasonic transducer includes a matching layer, and the matching layer includes the active surface. In Example 27, in the medical imaging device of Example 16, the ultrasonic transducer is configured as a two-dimensional imaging phased array assembly including a one-dimensional device.

[0023] In Example 28, in the medical imaging device of Example 16, the ultrasonic transducer includes a backing layer, the backing layer has a backing surface, and the backing surface includes a plurality of grooves in the backing layer.

[0024] In Example 29, the medical imaging system includes a magnetic field transmitting assembly configured to generate a magnetic field; a medical imaging catheter having a distal end region including a medical imaging module, wherein the medical imaging module comprises an ultrasonic transducer having an acoustic stack with an active surface on the opposite side of the backing surface, configured to convert acoustic energy received by the acoustic stack and to supply a corresponding detection signal; a magnetic tracking sensor assembly configured to detect the generated magnetic field and to supply a corresponding tracking signal related to the position of the magnetic tracking sensor assembly; a multilayer circuit assembly electrically and mechanically coupled to the ultrasonic transducer and the magnetic tracking sensor assembly, wherein the magnetic tracking sensor assembly has a coupling surface, the backing surface of the ultrasonic transducer is aligned with the coupling surface; and a controller operably coupled to the medical imaging module, configured to receive the detection signal and the tracking signal and to generate an image including the position of a two-dimensional imaging plane in three-dimensional space.

[0025] In Example 30, in the medical imaging system of Example 29, the controller is further configured to generate a three-dimensional map of the heart. In Example 31, in the medical imaging system of Example 29, the tracking signal further provides the orientation of the magnetic tracking sensor assembly, and the generated image includes the position and orientation of the two-dimensional imaging plane.

[0026] In Example 32, in the medical imaging system of Example 29, the ultrasonic transducer is configured as a two-dimensional imaging phased array assembly having a one-dimensional array device, and provides a plurality of two-dimensional images by manipulating acoustic beams across a two-dimensional plane.

[0027] In Example 33, a method of manufacturing a medical imaging device includes electrically coupling a magnetic tracking sensor assembly to a first portion of a flexible circuit, folding the remaining portion of the flexible circuit to form a flexible circuit stack, and electrically coupling an ultrasonic transducer to the flexible circuit, wherein the flexible circuit includes a first side surface of the first portion in contact with the backing surface and a second side surface opposite the first portion in contact with the magnetic tracking sensor assembly.

[0028] In Example 34, in the manufacturing method of Example 33, the flexible circuit stack is disposed on the magnetic tracking sensor assembly. In Example 35, in the manufacturing method of Example 34, the magnetic tracking sensor assembly is encapsulated in epoxy before folding the flexible circuit to form the flexible circuit stack.

[0029] Although several embodiments are disclosed, further embodiments of the present invention will become apparent to those skilled in the art from the following detailed description illustrating and describing exemplary embodiments of the invention. Accordingly, the drawings and detailed description should be considered as illustrative and not limiting. [Brief explanation of the drawing]

[0030] [Figure 1] Figure 1 is a schematic diagram showing an exemplary clinical setting for treating a patient and treating a patient's heart using a medical imaging system according to embodiments of the subject matter of this disclosure. [Figure 2] Figure 2 is a perspective view of a medical imaging device that can be used in conjunction with the exemplary medical imaging system shown in Figure 1. [Figure 3] Figure 3 is a schematic diagram showing the features of the medical imaging device shown in Figure 2. [Figure 4A] Figure 4A is a schematic diagram showing an example of the features of the medical imaging device shown in Figure 3, in a perspective view. [Figure 4B] Figure 4B is a schematic diagram showing a front view of an example of the features of the medical imaging device shown in Figure 4A. [Figure 4C] Figure 4C is a schematic diagram showing a side view of an example of the features of the medical imaging device shown in Figure 4A. [Figure 5] Figure 5 is a schematic diagram showing an example of the components of the medical imaging device shown in Figure 4A. [Figure 6] Figure 6 is a schematic diagram showing a perspective view of another example of the features of the medical imaging device shown in Figure 3. [Figure 7] Figure 7 is a schematic diagram showing an example of the components of the medical imaging device shown in Figure 6A. [Figure 8] Figure 8 is a block diagram showing an exemplary method for manufacturing the medical imaging device shown in Figure 3. [Figure 9]Figure 9 is a schematic diagram showing the components of an example of the features of the medical imaging device shown in Figure 4A, as a feature of the method for manufacturing the medical imaging device shown in Figure 8. [Modes for carrying out the invention]

[0031] While the present invention can accommodate various modifications and alternative forms, specific embodiments are shown as examples in the drawings and are described in detail below. However, the intention is not to limit the present invention to the specific embodiments described. Rather, the present invention is intended to encompass all modifications, equivalents, and alternative forms that fall within the scope of the invention as defined by the appended claims.

[0032] For the purpose of facilitating an understanding of the principles of this disclosure, examples shown in the drawings described below are provided for reference. The illustrated examples disclosed herein are not intended to be exhaustive or to limit this disclosure to the exact forms disclosed in the detailed description below. Rather, these exemplary embodiments are selected and described so that a person skilled in the art can utilize the teachings. It is also possible to use multiple (e.g., all) features in one example across all examples without departing from the scope of this disclosure. Accordingly, no drawing should be construed as having any dependency or requirement relating to any single component or combination of components shown in that drawing. Furthermore, various components shown in the drawings may be integrated in the examples with various other components shown in the drawings (or components not shown), all of which are included within the scope of this disclosure.

[0033] Figure 1 shows an exemplary clinical environment 10 for a medical procedure on a patient 20 using the medical imaging system 50 according to this disclosure, for example, a medical procedure on the patient 20's heart 30. The medical imaging system 50 includes a medical imaging catheter system 60 configured to be inserted into the patient 20 to image multiple parts of the patient's anatomical structure. The medical imaging catheter system 60 includes a medical imaging catheter 80, an introducer sheath 85, and an imaging console 90. Furthermore, the medical imaging catheter system 60 includes a variety of multiple connecting elements such as cables and tubes that operably connect multiple components of the medical imaging catheter system 60 to each other and to multiple components of the medical imaging system 50. In one example, the introducer sheath 85 is operable to provide a delivery conduit through which the medical imaging catheter 80 can be positioned at a specific target site within the patient's heart 30. Access to the patient's heart 30 can often be obtained via blood vessels, such as peripheral arteries or veins located in the groin, or possibly the shoulder or neck. Once access to the blood vessels is obtained, the medical imaging catheter 80 can be navigated into the patient's heart 30, for example, into the cardiac chambers.

[0034] Figure 2 shows an exemplary medical imaging catheter 80 suitable for use with a medical imaging catheter system 60. The medical imaging catheter 80 includes a proximal end region 202 and a distal end region 204. The medical imaging catheter 80 defines a longitudinal axis A passing through the centroid of the cross-section of the distal end region 204. The proximal end region 202 of the medical imaging catheter 80 includes a catheter hub 206, and the distal end region 204 is configured and positioned to be inserted into a patient 20. The medical imaging catheter 80 includes a shaft 208 sized to be inserted into areas of the patient 20 that are difficult to navigate, including blood vessels, cardiac chambers, gastrointestinal tract, urinary tract, and pulmonary system. The distal end region 204 includes an imaging module 100 that may extend, for example, into the patient's heart 30 and be located at the end of the shaft 208. The proximal end region 202 is configured to be connected to a medical imaging console 90. The imaging module 100 may be electrically connected to a plurality of elongated lead conductors extending along the catheter hub from the distal end region 204 to the proximal end region 202. The plurality of lead conductors may be insulated from each other within an insulating sheath, such as an insulating polymer sheath extending along the length of the shaft 208. The plurality of lead conductors may be electrically connected, for example, directly or via an intermediate electrical conductor such as a cable, to a plug configured to be mechanically and electrically connected to a medical imaging console 90 in the proximal end region 202. In one example, the imaging module 100 may include an imaging module cover 210 that forms the most distal tip 212, and the imaging module cover 210 is mechanically connected to the distal end 214 of the shaft 208.

[0035] Returning to Figure 1, the medical imaging console 90 includes one or more controllers, such as a controller, processor, or computer, which executes instructions or code, such as processor-executable instructions, stored in a non-temporary computer-readable medium such as a memory device or memory, to cause the operation of the medical imaging catheter system 60, for example, to be controlled or executed. In one example, the medical imaging console 90 may include a display 95. In one example, the medical imaging console 90 is configured to supply electrical signals, such as multiple simultaneous or temporally separated electrical signals, to an electrically connected medical imaging catheter 80 along multiple lead conductors to the imaging module 100. The medical imaging console 90 is also configured to receive electrical signals, such as multiple simultaneous or temporally separated electrical signals, from the electrically connected medical imaging catheter 80 along multiple lead conductors from the imaging module 100. The imaging module 100 includes an ultrasound imaging device. The medical imaging catheter system 60 is configured to send and receive acoustic energy to generate ultrasound images.

[0036] In one example, the ultrasound imaging device is configured as an intracardiac echocardiography (ICE) device. In other examples, the ultrasound imaging device can be configured as an endobronchial ultrasound (EBUS) device, an intravascular ultrasound (IVUS) device, or any other type of ultrasound imaging device. The ultrasound imaging device can acquire a wedge-shaped image, such as a 90-degree sector plane, from the side of the distal end of a medical imaging catheter 80 and display it on a medical imaging console 90. In one example of an ultrasound imaging device, a two-dimensional imaging phased array device, which includes multiple one-dimensional arrays, creates a two-dimensional image by steering an acoustic beam across a two-dimensional plane. Each acoustic beam, or scan line, generates an echo, which is measured and combined with other scan lines to form an ultrasound image. To create three-dimensional or four-dimensional (including time as a dimension) images, a two-dimensional array is applied to maneuver the beam across the entire three-dimensional volume, or two orthogonally positioned one-dimensional arrays scan each beam across their respective two-dimensional planes. Due to the physical properties of beamforming, exponentially more elements, interconnects, and power circuits are required, which includes increased costs and results in increased dimensions at the distal end of the medical imaging catheter. In many cases, the increased size of four-dimensional ICE transducers significantly reduces maneuverability in curved anatomical structures, making it more cumbersome to access many areas within the heart for closer imaging. Even when the increased cost and size are acceptable, medical imaging catheter systems still produce wedge-shaped images, such as a 90-degree sector plane with a plus / minus 45-degree angle on an axis perpendicular to the longitudinal axis of the distal end of the medical imaging catheter in side-firing ICE devices.In such a configuration, a typical medical imaging catheter system cannot generate images of the area anterior to the medical imaging catheter, i.e., in the longitudinal axis direction beyond the distal end.

[0037] To create three-dimensional or four-dimensional images using the medical imaging system 50 of this disclosure, the imaging module 100 includes a phased array ultrasound transducer, such as a one-dimensional phased array transducer combined with a magnetic tracking sensor assembly, and the medical imaging system 50 includes a magnetic tracking system 70, such as a magnetic tracking system 70 incorporated into a medical imaging catheter system 60. As included in the imaging module 100, the one-dimensional phased array ultrasound transducer provides signals for a two-dimensional image on a single plane, and the magnetic tracking sensor provides signals for position and orientation in six degrees of freedom. Using the imaging module 100, the medical imaging system 50 can generate and provide a two-dimensional image plane whose plane is located and oriented in three-dimensional space. The medical imaging system 50 allows the user to move and rotate the distal end region 104 to scan and image a three-dimensional volume. Furthermore, images generated using the medical imaging system 50 can be integrated with computed tomography (CT) images and magnetic resonance images (MRI) to provide additional information during treatment. Phased array ultrasound transducers, such as one-dimensional phased array transducers, are arranged in combination with a magnetic tracking sensor assembly within an imaging module cover 208 attached to the shaft 208 of the medical imaging catheter 80.

[0038] As shown in Figure 1, the magnetic tracking system 70 includes magnetic field transmitting assemblies 110a, 110b, ..., 110n, etc., a magnetic field controller 114, and a signal processor 116. The schematically shown magnetic field transmitting assemblies 110a, 110b, ..., 110n are configured to transmit or radiate electromagnetic signals that generate a magnetic field, and the patient 20 is placed within the magnetic field. The magnetic field controller 114 is configured to manage the operation of the magnetic field transmitting assemblies 110. For example, the magnetic field controller 114 includes a signal generator configured to supply a drive current, such as a variable drive current, to each magnetic field transmitting assembly 110a, 110b, ..., 110n in order to cause each magnetic field transmitting assembly 110 to transmit an electromagnetic field. In one example, to increase the signal-to-noise ratio, at least one transmitting assembly is placed near the magnetic tracking assembly module, for example, below the patient 20 (or below the patient's bed). The magnetic tracking system 70, including the magnetic field controller 114 and the signal processor 116, includes one or more controllers, processors, or computers that control or execute the operation of the magnetic tracking system 70 by executing instructions or code, such as processor-executable instructions, stored in a memory device or a non-temporary computer-readable medium such as memory.

[0039] In this example, the magnetic tracking sensor assembly of the imaging module 100 is configured to generate an electrical response to one or more magnetic fields generated by the magnetic field transmission assembly 110. For example, the magnetic tracking sensor assembly includes a magnetic field sensor such as an inductive sensing coil, or various sensing elements such as magnetoresistive (MR) sensing elements (e.g., anisotropic magneto-resistive (AMR), giant magneto-resistive (GMR), tunneling magneto-resistive (TMR), Hall effect sensing elements, colossal magneto-resistive (CMR), extraordinary magneto-resistive (EMR), and spin Hall sensing elements), giant magneto-impedance (GMI), or flux-gate sensing elements. In one example, the magnetic tracking sensor assembly includes multiple magnetic field sensors.

[0040] The magnetic tracking sensor assembly of the imaging module 100 is configured to detect the generated magnetic field and supply a tracking signal indicating the position and orientation of the magnetic tracking sensor assembly, i.e., the imaging module 100, in up to six degrees of freedom (i.e., movement in the x, y, and z axis directions, as well as pitch, yaw, and roll rotations). Generally, the number of degrees of freedom that a tracking system can track depends on the number of magnetic field sensors and magnetic field generators. For example, a tracking system with a single magnetic field sensor may not be able to track the roll angle and is therefore limited to tracking only five degrees of freedom (i.e., x, y, and z coordinates, as well as pitch and yaw angles). This is because even if a single magnetic field sensor "rolls" (rotates), the magnetic field detected by the single magnetic field sensor does not change. Multiple magnetic field sensors can be powered by voltage or current to drive or excite multiple elements of the multiple magnetic field sensors. The magnetic tracking sensor assembly of the imaging module 100 is communicably coupled to the signal processor 116, for example, via multiple leads to the imaging module 100 that are electrically coupled to the signal processor 116. Multiple magnetic field sensors receive voltage or current and generate a tracking signal in response to one or more of the generated magnetic fields, which is then supplied to the signal processor 116.

[0041] The tracking signal may include multiple magnetic field signals, each of which may be processed to extract a magnetic field component corresponding to one or more magnetic field transmitting assemblies 110a, 110b, ..., 110n. The tracking signal is communicated to a signal processor 116, which is configured to analyze the detected magnetic field signals to determine positional information, or positional and orientation information, corresponding to the magnetic tracking sensor assemblies of the imaging module 100. The positional information may include any kind of information associated with the position or location of the imaging module 100, such as position, relative position (e.g., position relative to another device), location, orientation, velocity, and acceleration. In some examples, the signal processor 116 may also be communicatively coupled to a reference magnetic sensor assembly to detect the magnetic field generated by the magnetic field transmitting assembly 110. The reference magnetic sensor assembly may be, for example, a reference sensor attached to a patient 20 or a bed, and in some examples, the reference sensor may be attached to or coupled to the magnetic field transmitting assembly 110 and communicatively coupled to the signal processor 116.

[0042] Figure 3 shows an exemplary medical imaging device 300 corresponding to the imaging module 100 described above. The medical imaging device 300 includes an ultrasonic transducer 302, a magnetic tracking sensor assembly 304, and a layered circuit assembly 306 electrically and mechanically coupled to the ultrasonic transducer 302 and the magnetic tracking sensor assembly 304. The magnetic tracking assembly includes a coupling surface. In one example, the medical imaging device 300 includes a longitudinal axis X, which corresponds to and may be coaxial with longitudinal axis A when the medical imaging device is positioned on the distal end region 204 of the medical imaging catheter 80. The ultrasonic transducer 302 and the magnetic tracking assembly 304 are coupled to the layered circuit assembly 306 such that they are aligned (for example, along an axis perpendicular to longitudinal axis A). In various examples, the multilayer circuit assembly 306 is one or more flexible printed circuit boards or integrated circuits (such as ASICs).

[0043] The ultrasonic transducer 302 includes an acoustic stack 308 comprising a plurality of layers forming an active surface or active side 310 opposite to the backing surface or backing side 312. For example, the acoustic stack is formed as layers along a vertical axis Z that is substantially perpendicular to the longitudinal axis X in the radial direction. In one example, the ultrasonic transducer 302 includes an active layer 314 positioned in contact with the backing layer 316. The active layer 314 may be formed from one or more known materials that can convert applied electrical signals into acoustic energy radiated from the surface of the active layer 314, such as an active side, and conversely convert acoustic energy absorbed by the active layer 314 into electrical signals. Several examples of materials suitable for the active layer 314 include piezoelectric ceramic materials, piezoelectric composite materials, piezoelectric plastics, barium titanate, lead zirconate titanate, lead metaniobate, and polyvinylidene fluoride. Other transducer technologies may include composite materials, single-crystal composite materials, and semiconductor devices (e.g., capacitive micromachined ultrasonic transducers (cMUTs) and piezoelectric micromachined ultrasonic transducers (pMUTs)). The backing layer 316 may be formed from a material suitable for absorbing, scattering, or attenuating acoustic energy, such as polymers, composite materials containing metal scattering particles or ceramic oxide scattering particles, and viscoelastic materials. The backing layer 316 attenuates the vibration of the active layer 314 to control the pulse length and pulse duration or vibration of the active layer 314 during radiation. When positioned adjacent to the active layer 314, the backing layer 316 absorbs, scatters, or attenuates the acoustic energy radiated from the active layer 314 to rapidly stop vibration when the application of an electrical signal is stopped.In some examples, the acoustic stack 308 may include matching layers, such as multiple matching layers, placed on the active layer 314 to form the active side. Matching layers are used in the acoustic stack of an ultrasonic transducer, for example, to facilitate the transfer of acoustic energy from the active layer to the propagation medium, or vice versa, within a bandwidth of frequencies around the center frequency of the device.

[0044] In one example, the ultrasonic transducer 302 is configured as a two-dimensional imaging phased array assembly, which includes multiple one-dimensional arrays and creates multiple two-dimensional images by steering an acoustic beam across a two-dimensional plane. Other configurations of the ultrasonic transducer 302 are also possible, and the ultrasonic transducer 302 may include linear arrays, curved arrays, 1.25-dimensional phased arrays, 1.5-dimensional phased arrays, 1.75-dimensional phased arrays, or two-dimensional arrays. In one example, the ultrasonic transducer 302 is configured as a side-firing ultrasonic transducer in the imaging module 100 of a medical imaging device 300 and a medical imaging catheter 80. Other configurations of the medical device 300 are also possible, such as a front-facing transducer, a radial transducer, or a combination thereof.

[0045] The magnetic tracking sensor assembly 304 includes a plurality of magnetic field sensors and a plurality of corresponding sensor circuits. For example, the magnetic tracking sensor assembly 304 includes first, second, and third magnetic field sensors and first, second, and third sensor circuits. Each sensor circuit may include a plurality of circuits having diodes and capacitors. The magnetic field sensors and sensor circuits may be mounted on separate dies and arranged adjacent to or near each other. The magnetic field sensors and sensor circuits may be electrically coupled to each other. In some examples, each magnetic field sensor and corresponding sensor circuit may be mounted on the same die or substrate in a monolithic design or the like. For example, a magnetic field sensor may be manufactured on top of a corresponding sensor circuit. The magnetic field sensor includes an inductive sensing coil or various sensing elements, such as an MR sensing element, GMI sensing element, or fluxgate sensing element, which may include AMR sensing elements, GMR sensing elements, TMR sensing elements, Hall effect sensing elements, CMR sensing elements, EMR sensing elements, and spin Hall sensing elements. Multiple magnetic field sensors are configured to detect magnetic fields, such as those generated by the magnetic field transmission assembly 110, and to generate response detection signals.

[0046] Multiple magnetic field sensors may be arranged in a dual-axis, six-degree-of-freedom configuration. For example, the first and second magnetic field sensors are oriented so that their primary sensing direction aligns with the longitudinal axis X of the medical imaging device 300. The third magnetic field sensor is oriented so that its primary sensing direction aligns with an axis perpendicular to the longitudinal axis X. In some examples, the multiple magnetic field sensors are arranged in a three-axis, six-degree-of-freedom configuration. In such examples, the primary sensing directions of the multiple magnetic field sensors are orthogonal to each other. In some examples, one or more of the multiple magnetic field sensors are dual-axis sensors with two primary sensing directions or tri-axis sensors with three primary sensing directions. The first, second, and third magnetic field sensors are configured to generate response sensing signals in response to a magnetic field. The sensing signals are used to determine the position and orientation of the sensor assembly 300.

[0047] The multilayer circuit assembly 306 includes a first side 320 in contact with the backing side 312 of the ultrasonic transducer 302, and the multilayer circuit assembly 306 includes a second opposite side 322 in contact with the magnetic tracking sensor assembly 304. In one example, the multilayer circuit assembly 306 may include a printed circuit or flex circuit electrically coupled to the ultrasonic transducer 302 and the magnetic tracking sensor assembly 304. In this example, the magnetic tracking sensor assembly 304 includes a cover 324, such as an epoxy sealant, for rigidity. The first side 320 and the second side 322 may be on opposing surfaces of the multilayer circuit assembly 306. Alternatively, if the multilayer circuit assembly 306 is folded on itself (or folded an odd number of times on itself), the first side 320 and the second side 322 are on the same surface when the multilayer circuit assembly 306 is not folded, and such a structure ensures that the ultrasonic transducer 302 and the magnetic tracking sensor assembly 304 are on opposing surfaces of the multilayer circuit assembly 306. The multilayer circuit assembly 306 can be folded multiple times to form a folded stacked circuit assembly, for example, by being folded multiple times between the ultrasonic transducer 302 and the magnetic tracking sensor assembly 304, or by being folded below the magnetic sensor assembly 304, and stacked along the vertical axis Z.

[0048] The ultrasonic transducer 302 includes multiple electrical connectors attached to multiple mounting pads of the multilayer circuit assembly 306. Multiple electrical signals can be applied to the active layer 314 via the multiple electrical connectors 306. For example, a voltage can be applied to the active layer 314 via the multiple electrical connectors of the flex circuit of the multilayer circuit assembly 306 to generate a pulse of acoustic energy that is radiated from the active layer 314 toward an imaging target. The pulse of acoustic energy may include one or more acoustic waves and may have associated pulse duration and pulse length. When the pulse of acoustic energy is reflected by the imaging target and this reflection is received by the active layer 314, the active layer 314 may generate an electrical signal, which can be measured or detected and supplied from a medical imaging device via the electrical connectors 306. This electrical signal can be used to generate an ultrasonic image of the target via a medical imaging system 50. Similarly, the magnetic tracking sensor assembly 304 includes multiple electrical connectors attached to multiple mounting pads on the second side 322 of the multilayer circuit assembly 306, which receive multiple sensing signals and supply them to the medical imaging system 50 to determine the position and orientation of the medical imaging device 300.

[0049] When supplied from the medical imaging device 300, multiple detection signals for ultrasound imaging are combined with multiple tracking signals in the medical imaging system 50, for example, via a controller, thereby enabling the determination of both the two-dimensional imaging plane and the position, or both position and orientation, of the two-dimensional imaging plane in three-dimensional space for the image. The medical imaging device 300 is fitted with a tracking system and software program executed by the medical imaging system 50 to enable movement and rotation to scan and image a three-dimensional volume and construct a three-dimensional image. Furthermore, the medical device 300 can enable image integration with CT or MRI images to provide additional information during the procedure. By generating multiple signals that provide information for generating two-dimensional and four-dimensional images and maps, the medical imaging device 300 addresses previous problems with two-dimensional and four-dimensional TEE and ICE devices, enabling clinicians to guide procedures at a cost and size comparable to two-dimensional imaging ICE devices. For example, an ultrasound transducer 302 consisting of a one-dimensional phased array transducer applied to a medical imaging device 300 can provide robust imaging in a low-cost, compact form factor. In one example, the imaging device may be mounted on a 3.0 mm (9 French) catheter. Alternatively, for example, applying an ultrasound transducer 302 consisting of a two-dimensional phased array for four-dimensional ultrasound imaging to the medical imaging device 300 can provide additional information useful when generating a three-dimensional map of anatomical structures, such as the anatomical structure of the heart.

[0050] Figures 4A to 4C show an exemplary medical imaging device 400 configured according to a medical imaging device 300. In this example, the medical imaging device 400 is mounted on a medical imaging catheter 80. The medical imaging device 400 includes an ultrasonic transducer 402, a magnetic tracking sensor assembly 404, and a flexible circuit 406 electrically coupled to the ultrasonic transducer 402 and the magnetic tracking sensor assembly 404. In one example, the medical imaging device 400 includes a longitudinal axis X1, which corresponds to and may be coaxial with longitudinal axis A when the medical imaging device 400 is positioned on the distal end region 204 of the medical imaging catheter 80. In one example, the medical imaging device 400 may include a distal tip cover 450 suitable for attachment to the distal end region 204 of the medical imaging catheter 80 (e.g., abutting against the catheter shaft 208), or in some examples, may be covered by the distal tip cover 450. In some cases, the distal tip cover 450 may be formed as a focusing lens.

[0051] The ultrasonic transducer 402 is formed as an acoustic stack 408 having, for example, an active layer 414, a backing layer 416, and a matching layer 418. The matching layer 418 provides the active side 410 of the acoustic stack 408, and the backing layer 416 provides the backing side 412 of the acoustic stack 408. The acoustic stack 408 is arranged as layers along a vertical axis Z1 that is substantially perpendicular to the longitudinal axis X1 in the radial direction. The length is measured along the longitudinal axis X1, and the height is measured along axis Z1. The width, such as the width of the backing side 412, is measured along a transverse axis Y1 that is perpendicular to the longitudinal axis X1 and the vertical axis Z1. In one example, the backing side 412 includes a plurality of spaced grooves having a depth along the vertical axis Z1 within the backing layer 416 in order to reduce the thickness of the backing layer 416 and the acoustic stack 408. Although not limited to any particular theory, the spaced grooves can reduce reflections by causing phase cancellation of acoustic energy as it reflects off the backing side 412 and returns to the active layer 414. The configuration of the ultrasonic transducer 402 and the acoustic stack 408 is illustrated and described in the U.S. Patent Application Publication No. 2022 / 0409170 by Andrew Graveley et al., titled "ULTRASOUND TRANSDUCER," which has been assigned to the current assignee, and is incorporated herein by reference in its entirety.

[0052] The magnetic tracking sensor assembly 404 in this example incorporates multiple TMR sensors directly mounted to a flex circuit 406. For example, the magnetic tracking sensor assembly 404 includes a biaxial configuration having three magnetic field sensors 430a, 430b, and 430, and corresponding sensor circuits 432a, 432b, and 432c. For example, the sensor circuits 432a, 432b, and 432c may include multiple diodes and capacitors. The configuration of the magnetic tracking sensor assembly 404 having the magnetic field sensors 430a, 430b, and 430c and the sensor circuits 432a, 432b, and 432c is illustrated and described in U.S. Patent No. 11,141,567 by Steven J. Meyer et al., titled "ELECTRICAL ARRANGEMENTS FOR SENSOR ASSEMBLIES IN ELECTROMAGNETIC NAVIGATION SYSTEMS," which is incorporated herein by reference in its entirety.

[0053] The flex circuit 406 includes a first side 420 in contact with the backing side 412 of the ultrasonic transducer 402, and the flex circuit 406 includes a second opposite side 422 in contact with the magnetic tracking sensor assembly 404. In this example, the first side 420 and the second side 422 are located on opposing surfaces of the flex circuit 406. The ultrasonic transducer 402 includes a plurality of electrical coupling members 440, which are operably coupled to the active layer 414 and extend along the longitudinal sides 460, 462 of the ultrasonic transducer 402. These electrical coupling members 440 are attached to the flex circuit on the first side 420 of the flex circuit 406, such as on the first surface of the flex circuit 406. The magnetic tracking sensor assembly 404, in particular the magnetic field sensors 430a, 430b, 430c and the sensor circuits 432a, 432b, 432c, includes a plurality of electrical connectors 442 mounted on a second side 422 of the flex circuit 406, such as on the opposite surface of the flex circuit 406. The flex circuit 406 includes a distal portion 452 having a plurality of exposed electrical mounting pads 444 on the surface of the flex circuit 406. The plurality of electrical mounting pads 444 are conductively coupled via a plurality of conductive elements 448 to a plurality of electrical lead pads (not shown) located on the proximal portion 454 of the flex circuit 406. The plurality of electrical lead pads may be electrically coupled to a plurality of leads in the catheter shaft 208 extending to the proximal end 202 of the catheter in order to supply electrical signals to a plurality of connectors on the proximal end 202 of the catheter.

[0054] When the first side 420 and the second side 422 of the flex circuit 406 are on opposing surfaces, one or both surfaces may include a plurality of exposed electrical mounting pads 444. The magnetic tracking sensor assembly 404 is coupled to the second side 422 of the flex circuit 406 by attaching the magnetic field sensors 430a, 430b, 430c and the electrical connectors 442 of the sensor circuits 432a, 432b, 432c, etc., to the associated electrical mounting pads 444. The backing side 416 of the ultrasonic transducer 402 may abut or be attached to the first side 420 of the flex circuit 406 so that the active side 414 of the acoustic stack does not face the flex circuit 406, and the plurality of electrical connectors 440 of the ultrasonic transducer 402 are electrically coupled to the associated plurality of electrical mounting pads 444. In one example, the electrical coupling members and connectors 440, 442 are coupled to the associated electrical connectors via wire bonds or other suitable connections. Other examples include electrically coupling the ultrasonic transducer 402 and the magnetic tracking sensor assembly via flip chips, through-silicon vias, and fan-out wafer-level packaging. In this example, the magnetic tracking sensor assembly 404, electrically coupled to the flex circuit 406, is covered with an epoxy sealant 424 placed on the second side surface 422 of the magnetic tracking sensor assembly 404 and the flex circuit 406 for purposes such as rigidity or protection of the components of the magnetic tracking sensor assembly 404.

[0055] In many cases, the width of a flexible circuit 406 having multiple conductive elements 448 spaced laterally apart may be several times greater than the width of the acoustic stack 408 (e.g., measured along the width of the backing side 412) or the width of the magnetic tracking sensor assembly 404 placed on the flexible circuit 406. In such cases, the width of the medical imaging device 400 may be reduced by folding, rolling, or repeatedly folding or rolling the flexible circuit 406 so that it fits within the distal tip cover 450. In one example, the flexible circuit 406 is folded to form a flexible circuit stack 466 such that the width of the medical imaging device 400 is approximately the width of the backing side 412 or the width between the vertically extending electrical connectors 440 of the ultrasonic transducer 402.

[0056] These examples illustrate a medical imaging device 400 having a flexible circuit stack 466 positioned below an ultrasonic transducer 402 and a magnetic tracking sensor assembly 404. The flexible circuit 406 folds to form a flexible circuit stack 466 and includes a plurality of flexible circuit layers 468 arranged along a vertical axis Z1. The flexible circuit 406 includes a first portion 470, which includes a first side 420 in contact with the backing side 412 of the ultrasonic transducer 402 and a second side 422 electrically coupled to the magnetic tracking sensor assembly 404 and containing a sealant 424. The first portion 470 of the flexible circuit 406 extends to a second portion 472, i.e., a vertical portion 472 folded approximately perpendicular to the first portion 470, which has a height along the Z1 axis sufficient to exceed the height of the magnetic tracking sensor assembly 404 or (if included) the sealant 424. The second portion 472 is folded from the first portion 470 so that it fits within the width of, for example, the backing side 412 within the electrical connector 440. The second portion 472 extends to a folded flex circuit stack 466 located below the magnetic tracking sensor assembly 404 (not between the ultrasonic transducer 402 and the magnetic tracking sensor assembly 404). The flex circuit stack 466 includes a third portion 474 that extends from the second portion 472 and is folded substantially perpendicular to the magnetic tracking sensor assembly 404. The flex circuit stack 466 may include an additional layer folded on top of the third portion 474.

[0057] Figure 5 shows a cross-section of an exemplary flex circuit 406 before bending, after the magnetic tracking sensor assembly 404 has been electrically coupled to a plurality of mounting pads 444 and covered with epoxy sealant 424. The flex circuit 406 includes a distal portion 502 which may extend to the distal end of the distal tip cover 450 and a proximal portion 504 which may be positioned near the catheter shaft 208. The flex circuit 406 includes a plurality of conductive elements 448, for example, a first group of substantially longitudinally extending conductive elements 506 which are associated with and electrically coupled to the magnetic tracking sensor assembly 404, and a second set of substantially longitudinally extending conductive elements 508 which are associated with and electrically coupled to a plurality of electrical connectors 440 of the ultrasonic transducer 402. The flex circuit 406 includes a first portion 470 which contains the magnetic tracking sensor assembly 404 electrically coupled to a plurality of mounting pads 444 covered with epoxy sealant 424 on a second side surface 422. The second portion 472 is adjacent to the first portion 470. The boundary between the second portion 472 and the remaining third portion 474 includes a first perforation set 510 that extends longitudinally. Similarly, the boundaries between additional remaining portions 476, 478, 480, which can form additional layers of the flex circuit stack 466, may include additional perforation sets 512, 514, 516. During manufacturing, the flex circuit 406 can be folded longitudinally along the perforation sets 510-516 to create the flex circuit stack 466. Also, an exemplary flex circuit 406 includes a distal region 520 containing the distal ends of a second set of conductive elements 508, which may be folded laterally toward the proximal portion 504 to provide the ends of the second set of conductive elements 508 for mounting to multiple electrical connectors 440 of the ultrasonic transducer 402.

[0058] Figure 6 shows an exemplary medical imaging device 600 configured according to the medical imaging device 400. In this example, the medical imaging device 600 is mounted on a medical imaging catheter 80. The medical imaging device 600 includes an ultrasonic transducer 602, a magnetic tracking sensor assembly 604, and a flexible circuit 606 electrically coupled to the ultrasonic transducer 602 and the magnetic tracking sensor assembly 604. In this example, the medical imaging device 600 includes a longitudinal axis X2, which corresponds to and may be coaxial with longitudinal axis A when the medical imaging device 600 is positioned on the distal end region 204 of the medical imaging catheter 80. In this example, the medical imaging device 600 may include a distal tip cover 650 suitable for mounting to the distal end region 204 of the medical imaging catheter 80 (e.g., abutting against the catheter shaft 208), or in some examples, may be covered by the distal tip cover 650.

[0059] The ultrasonic transducer 602 is formed, for example, as an acoustic stack 608 having an active layer 614, a backing layer 616, and a matching layer 618. The matching layer 618 provides the active side 610 of the acoustic stack 608, and the backing layer 616 provides the backing side 612 of the acoustic stack 608. The acoustic stack 608 is arranged as layers along a vertical axis Z2 that is substantially perpendicular to the longitudinal axis X2 in the radial direction.

[0060] The magnetic tracking sensor assembly 604 in this example incorporates multiple guide sensors directly mounted to a second side 622. For example, the magnetic tracking sensor assembly 604 has a two-axis configuration with two guide sensors, which are angled away from the longitudinal axis X2 toward the proximal end 654 and converge toward the distal end 652 at a selected angle W. In one example, these guide sensors are angled at least 11 degrees W for effective orientation sensitivity along the longitudinal axis X2, which the catheter shaft 208 is likely to rotate around during normal use, and are housed in a medical imaging device 600.

[0061] The flex circuit 606 includes a first side 620 in contact with the backing side 612 of the ultrasonic transducer 602, and the flex circuit 606 includes a second opposite side 622 in contact with the inductive sensors of the magnetic tracking sensor assembly 604. The ultrasonic transducer 602 includes a plurality of electrical connectors 640 attached to the flex circuit on the first side 620 of the flex circuit 606, and the plurality of inductive sensors of the magnetic tracking sensor assembly 604 include a plurality of electrical connectors 642 attached to the second side 622 of the flex circuit 606. The flex circuit 606 includes a distal portion 652 having a plurality of exposed electrical mounting pads 644 on the surface of the flex circuit 606. The plurality of electrical mounting pads 644 are conductively coupled via a plurality of conductive elements 648 to a plurality of electrical lead pads (not shown) located in the proximal portion 654 of the flex circuit 606. The magnetic tracking sensor assembly 404 is coupled to the second side 622 of the flexible circuit 606, for example, by attaching the electrical connectors 640 of the multiple induction sensors to the associated electrical mounting pads 644. The backing side 612 of the ultrasonic transducer 602 may abut or be attached to the first side 620 of the flexible circuit 606, and the multiple electrical connectors 640 of the ultrasonic transducer 602 are electrically coupled to the associated electrical mounting pads 644. In one example, the electrical connectors 640, 642 are coupled to the associated electrical connectors via wire bonds. In this example, the magnetic tracking sensor assembly 604 electrically coupled to the flexible circuit 606 is covered with an epoxy sealant 624, which is placed on the magnetic tracking sensor assembly 604 and the second side 622 of the flexible circuit 606 for purposes such as rigidity or protection of the components of the magnetic tracking sensor assembly 604.

[0062] These examples illustrate a medical imaging device 600 having a flexible circuit stack 666 positioned below an ultrasonic transducer 602 and a magnetic tracking sensor assembly 604. The flexible circuit 606 folds to form the flexible circuit stack 666 and includes a plurality of flexible circuit layers 668 arranged along the vertical axis Z2. The flexible circuit 606 includes a first portion 670, which includes a first side 620 in contact with the backing side 612 of the ultrasonic transducer 602 and a second side 622 electrically coupled to the magnetic tracking sensor assembly 604 and containing a sealant 624. The first portion 670 of the flexible circuit 606 extends to a second portion 672, i.e., a vertical portion 672 folded approximately perpendicular to the first portion 670, which has a height along the Z2 axis sufficient to exceed the height of the magnetic tracking sensor assembly 604 or (if included) the sealant 624. The second portion 672 is folded from the first portion 670 so that it fits within the width of, for example, the backing side 612 within the electrical connector 640. The second portion 672 extends to a folded flex circuit stack 666 located below the magnetic tracking sensor assembly 604 (not between the ultrasonic transducer 602 and the magnetic tracking sensor assembly 604). The flex circuit stack 666 includes a third portion 674 that extends from the second portion 672 and is folded substantially perpendicular to the magnetic tracking sensor assembly 604. The flex circuit stack 666 may include an additional layer folded on top of the third portion 674.

[0063] Figure 7 shows a cross-section of an exemplary flex circuit 606 before bending, after the magnetic tracking sensor assembly 604 has been electrically coupled to a plurality of mounting pads 644 and covered with epoxy sealant 624. The flex circuit 606 includes a distal portion 702 which may extend to the distal end of the distal tip cover 650 and a proximal portion 704 which may be positioned near the catheter shaft 208. The flex circuit 606 includes a plurality of conductive elements 648, for example, a first group of conductive elements 706 that extends substantially longitudinally and is associated with and electrically coupled to the magnetic tracking sensor assembly 604, and a second set of conductive elements 708 that extends substantially longitudinally and is associated with and electrically coupled to a plurality of electrical connectors 640 of the ultrasonic transducer 602. The flex circuit 606 includes a first portion 670 which contains the magnetic tracking sensor assembly 604 electrically coupled to a plurality of mounting pads 644 covered with epoxy sealant 624 on a second side surface 622. The second portion 672 is adjacent to the first portion 670. The boundary between the second portion 672 and the third portion 674 includes a first set of perforations 710 that extends longitudinally. Similarly, the boundaries between the remaining portions 676, 678, and 680 that form additional layers of the flex circuit stack 666 may include additional sets of perforations 712, 714, and 716. During manufacturing, the flex circuit 606 can be folded longitudinally along the sets of perforations 710-716 to create the flex circuit stack 666.

[0064] Figure 8 shows an exemplary method 800 for manufacturing medical devices 300 or 400, 600. In 802, a magnetic tracking sensor assembly is electrically coupled to a first portion of a flexible circuit. In one example, the first portions of the flexible circuit are first portions 470, 670 on flexible circuits 406, 606, respectively. The magnetic tracking sensor assembly may be wire-bonded to several exposed pads on the flexible circuit and, in some examples, then epoxy-sealed. In 804, the remaining portion of the flexible circuit is folded to form a flexible circuit stack. For example, the flexible circuit stack is placed on the magnetic tracking sensor assembly, and the magnetic tracking sensor assembly may be epoxy-sealed before folding. In 806, an ultrasonic transducer is electrically coupled to the flexible circuit, and the flexible circuit includes a first side of the first portion in contact with a backing side and a second side opposite the first portion in contact with the magnetic tracking sensor assembly. In one example, the ultrasonic transducer is electrically coupled to the flexible circuit in 804 before the flexible circuit is folded to form a flexible circuit stack. In this example, the portion of the flexible circuit extending from the longitudinal side of the ultrasonic transducer is folded before the ultrasonic transducer is diced to separate the multiple bulk layers into individual elements. In another example, the ultrasonic transducer is electrically coupled to the flexible circuit before the magnetic tracking sensor assembly in 802.

[0065] Figure 9 shows an embodiment in which an assembly 900 containing a flexible circuit is folded to form a flexible circuit stack, such as in 804 of Method 800. The assembly 900 includes a magnetic tracking sensor assembly 902 electrically coupled to the flexible circuit 904, as in 802. This assembly further includes an ultrasonic transducer 906 electrically coupled to the flexible circuit 904. In the embodiment shown in Figure 9, the flexible circuit 904 is cut along a plurality of perforation lines 908 and folded along fold lines FOLD1 to FOLD12 to form a flexible circuit stack. For example, the flexible circuit 904, which includes the attached magnetic tracking sensor assembly 902 and ultrasonic transducer 906, is cut along a plurality of perforation lines 908 and folded along fold line FOLD1, then along fold line FOLD2, then along fold line FOLD3, ..., then along fold line FOLD12 in that order.

[0066] Various modifications and additions can be made to the exemplary embodiments described without departing from the scope of this disclosure. For example, while the embodiments described above refer to specific features, the scope of the invention also includes embodiments having different combinations of features, and embodiments that do not include all of the described features. Accordingly, the scope of the invention is intended to encompass all such alternative forms, modifications, and variations included in the claims, along with all their equivalents.

Claims

1. A medical imaging device, An ultrasonic transducer having an acoustic stack including an active surface opposite to the backing surface, Magnetic tracking sensor assembly and A multilayer circuit assembly electrically and mechanically coupled to the ultrasonic transducer and the magnetic tracking sensor assembly, wherein the magnetic tracking sensor assembly has a coupling surface, comprising: A medical imaging device in which the backing surface is aligned with the bonding surface.

2. The medical imaging device according to claim 1, wherein the multilayer circuit assembly includes a flexible circuit.

3. The medical imaging device according to claim 1 or 2, wherein the flexible circuit is substantially planar and comprises a first portion and a second portion, the magnetic tracking sensor assembly and the ultrasonic transducer are electrically coupled to the first portion, and the second portion is folded below the first portion.

4. The medical imaging device according to any one of claims 1 to 3, wherein the magnetic tracking sensor assembly is disposed within a sealing material.

5. The medical imaging device according to claim 4, wherein the sealing material is epoxy.

6. The medical imaging device according to any one of claims 1 to 5, wherein the magnetic tracking sensor assembly includes one of a plurality of tunnel magnetoresistive sensors and a plurality of inductive sensors.

7. The medical imaging device according to any one of claims 1 to 6, wherein the ultrasonic transducer includes a matching layer, and the matching layer includes the active surface.

8. The medical imaging device according to any one of claims 1 to 7, wherein the ultrasonic transducer includes a backing layer, the backing layer has a backing surface, and the backing surface includes a plurality of grooves in the backing layer.

9. The medical imaging device according to any one of claims 1 to 8, wherein the ultrasonic transducer includes a phased array transducer.

10. The medical imaging device according to any one of claims 1 to 9, wherein the medical imaging device is included in a distal cover attached to a catheter shaft.

11. The medical imaging device according to claim 10, wherein the catheter is included in an imaging system further comprising a plurality of magnetic field transmitting assemblies.

12. The medical imaging device according to claim 11, further comprising a controller operably coupled to the medical imaging device, the controller configured to receive a detection signal from the ultrasonic transducer and a tracking signal from the magnetic tracking sensor assembly, and to generate an image including the position and orientation of a two-dimensional imaging plane in three-dimensional space.

13. The medical imaging device according to claim 1, wherein the magnetic tracking assembly is attached to the multilayer circuit assembly via a wire bonding process.

14. The medical imaging device according to claim 12, wherein the multilayer circuit assembly is folded into a stack, and the stack is arranged on the magnetic tracking assembly.

15. The medical imaging device according to any one of claims 1 to 14, wherein the ultrasonic transducer is configured as a two-dimensional imaging phased array assembly including a one-dimensional device.

16. A medical imaging device, An ultrasonic transducer having an acoustic stack including an active surface opposite to the backing surface, Magnetic tracking sensor assembly and A multilayer circuit assembly electrically and mechanically coupled to the ultrasonic transducer and the magnetic tracking sensor assembly, wherein the magnetic tracking sensor assembly has a coupling surface, comprising: A medical imaging device in which the backing surface is aligned with the bonding surface.

17. The medical imaging device according to claim 16, wherein the multilayer circuit assembly includes a flexible circuit.

18. The medical imaging device according to claim 17, wherein the flexible circuit includes a first portion connected to a folded stack, the magnetic tracking sensor assembly and the ultrasonic transducer are electrically coupled to the first portion, and the folded stack is folded below the first portion.

19. The medical imaging device according to claim 18, wherein the flexible circuit includes a plurality of longitudinally extending sets of conductive elements arranged between a plurality of longitudinally extending perforations.

20. The medical imaging device according to claim 18, wherein each of the ultrasonic transducer and the magnetic tracking sensor assembly includes a plurality of electrical connections electrically coupled to a plurality of sets of conductive elements extending in the longitudinal direction.

21. The medical imaging device according to claim 16, wherein the magnetic tracking sensor assembly is disposed within a sealing material.

22. The medical imaging device according to claim 21, wherein the sealing material is epoxy.

23. The medical imaging device according to claim 16, wherein the magnetic tracking sensor assembly includes one of a plurality of tunnel magnetoresistive sensors and a plurality of inductive sensors.

24. The medical imaging device according to claim 23, wherein each of the plurality of induction sensors includes longitudinal portions that are angled toward each other.

25. The medical imaging device according to claim 23, wherein the magnetic tracking sensor assembly includes a plurality of tunnel magnetoresistance sensors electrically coupled to a plurality of corresponding sensor circuits.

26. The medical imaging device according to claim 16, wherein the ultrasonic transducer includes a matching layer, and the matching layer includes the active surface.

27. The medical imaging device according to claim 16, wherein the ultrasonic transducer is configured as a two-dimensional imaging phased array assembly including a one-dimensional device.

28. The medical imaging device according to claim 16, wherein the ultrasonic transducer includes a backing layer, the backing layer has a backing surface, and the backing surface includes a plurality of grooves in the backing layer.

29. A medical imaging system, A magnetic field transmitting assembly configured to generate a magnetic field, A medical imaging catheter having a distal end region including a medical imaging module, wherein the medical imaging module is An ultrasonic transducer having an acoustic stack including an active surface on the opposite side of the backing surface, wherein the ultrasonic transducer is configured to convert acoustic energy received by the acoustic stack and supply a corresponding detection signal, A magnetic tracking sensor assembly configured to detect a generated magnetic field and to supply a corresponding tracking signal related to the position of the magnetic tracking sensor assembly, A multilayer circuit assembly electrically and mechanically coupled to the ultrasonic transducer and the magnetic tracking sensor assembly, wherein the magnetic tracking sensor assembly has a coupling surface, and the multilayer circuit assembly comprises The backing surface is aligned with the bonding surface, and the medical imaging catheter A medical imaging system comprising: a controller operably coupled to the medical imaging module, configured to receive the detection signal and the tracking signal, and to generate an image including the position of a two-dimensional imaging plane in three-dimensional space.

30. The medical imaging system according to claim 29, wherein the controller is further configured to generate a three-dimensional map of the heart.

31. The medical imaging system according to claim 29, wherein the tracking signal further provides the orientation of the magnetic tracking sensor assembly, and the generated image includes the position and orientation of the two-dimensional imaging plane.

32. The medical imaging system according to claim 29, wherein the ultrasonic transducer is configured as a two-dimensional imaging phased array assembly having a one-dimensional array device, and provides a plurality of two-dimensional images by manipulating an acoustic beam across a two-dimensional plane.

33. A method for manufacturing a medical imaging device, The magnetic tracking sensor assembly is electrically coupled to the first part of the flexible circuit, The remaining portion of the flexible circuit is folded to form a flexible circuit stack, A method for manufacturing a medical imaging device, comprising electrically coupling an ultrasonic transducer to a flexible circuit, wherein the coupling includes a first side surface of the first portion in contact with a backing surface and a second side surface opposite to the first portion in contact with the magnetic tracking sensor assembly.

34. The method for manufacturing a medical imaging device according to claim 33, wherein the flexible circuit stack is arranged on the magnetic tracking sensor assembly.

35. The method for manufacturing a medical imaging device according to claim 34, wherein the magnetic tracking sensor assembly is sealed in epoxy before the flexible circuit is folded to form the flexible circuit stack.

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