Patent Publication Number: US-2020289089-A1

Title: Ultrasound device including a detachable acoustic coupling pad

Description:
BACKGROUND 
     Technical Field 
     The present disclosure pertains to physiological sensing devices, and more particularly to such devices for acquiring ultrasound data using an acoustic coupling between the device and a patient. 
     Description of the Related Art 
     Ultrasound imaging is typically performed in a clinical setting, by trained ultrasound experts, utilizing ultrasound systems or devices that are specifically designed to acquire ultrasound data. In order to enhance the reception of this physiological data, an ultrasound transmission gel or ultrasound gel is usually applied at the face of the ultrasound sensor device or on the skin of the patient by a physician or other clinician. The ultrasound gel is typically an electrically conductive material, such as a water-based gel, and when ultrasound gels are applied to an area of skin of the patient that covers a target tissue area, it eliminates any air between the sensor and the skin. The gel forms an acoustic pathway between the sensor and the skin and facilitates the transmission of ultrasound signals. 
     BRIEF SUMMARY 
     The present disclosure provides a multifunctional device capable of sensing ultrasound data and electrocardiogram (ECG) data with the same device. 
     In various embodiments, the present disclosure provides a device that incorporates an acoustic coupling pad capable of providing an acoustic pathway between the device and a patient, which facilitates acoustic coupling without the use of conventional ultrasound sensing gels. 
     Moreover, in various embodiments, the present disclosure provides an acoustic coupling pad that can be attached at the sensor face of an ultrasound device at a position that is spaced apart from one or more ECG sensor leads on the sensor face. The acoustic coupling pad provides acoustic coupling between the device and a patient during a diagnostic process, while preventing the ECG sensor leads from being electrically connected or short-circuited to each other through the acoustic coupling pad. 
     Additionally, in various embodiments, the present disclosure provides a general use acoustic coupling pad that can be easily attached and detached at the sensor face of any medical devices without having to use sensing gels that may discomfort the patient. 
     In an embodiment, a device is provided that includes an ultrasound sensor on a sensor face of the device, an electrocardiogram (ECG) sensor on the sensor face of the device, and an acoustic coupling pad on the ultrasound sensor, the ECG sensor being spaced apart from the acoustic coupling pad. The ultrasound sensor includes an ultrasound transducer array and an ultrasound lens on the ultrasound transducer array. The acoustic coupling pad is removably attached to the ultrasound lens. 
     In another embodiment, an acoustic coupling pad for an ultrasound device is provided that includes an acoustically conductive body having a first surface and a second surface opposite the first surface, a biocompatible coating layer on the first surface, and an adhesive layer on the second surface. The biocompatible coating layer includes biocompatible silicone. The thickness of the acoustic coupling pad is less than 10 mm. The acoustically conductive body includes a synthetic rubber. The acoustic coupling pad may be attached to a backing. The acoustic coupling pad may be removably secured to the backing by the adhesive layer. 
     In yet another embodiment, an ultrasound probe is provided that includes a housing, a sensor face exposed at one end of the housing, an ultrasound transducer array, an ultrasound lens on the ultrasound transducer array and adjacent to the sensor face, and an acoustic coupling pad removably attached to the ultrasound lens. The ultrasound lens defines at least a portion of the sensor face of the ultrasound probe, and the acoustic coupling pad extends outwardly beyond the sensing face. The ultrasound lens is recessed with respect to the sensor face of the ultrasound probe. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       For a better understanding of the embodiments, reference will now be made by way of example only to the accompanying drawings. In the drawings, identical reference numbers identify similar elements or acts. The sizes and relative positions of elements in the drawings are not necessarily drawn to scale. For example, the shapes of various elements and angles are not necessarily drawn to scale, and some of these elements may be enlarged and positioned to improve drawing legibility. Further, the particular shapes of the elements as drawn are not necessarily intended to convey any information regarding the actual shape of the particular elements, and may have been solely selected for ease of recognition in the drawings. 
         FIG. 1  is a perspective view illustrating a device having an ultrasound sensor, an electrocardiogram (ECG) sensor, and an acoustic coupling pad, in accordance with one or more embodiments of the present disclosure. 
         FIG. 2  is an enlarged perspective view of a sensor portion of the device shown in  FIG. 1  without the acoustic coupling pad, in accordance with one or more embodiments. 
         FIG. 3  is an enlarged perspective view of the pad portion and the sensor portion of the device shown in  FIG. 1 , in accordance with one or more embodiments. 
         FIG. 4  is a cross-sectional view taken along the cut-line  4 - 4  of  FIG. 3 , illustrating further details of the pad portion and the sensing portion of the device, in accordance with one or more embodiments. 
         FIG. 5  is a perspective view of an acoustic coupling pad, in accordance with one or more embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description, certain specific details are set forth in order to provide a thorough understanding of various disclosed embodiments. However, one skilled in the relevant art will recognize that embodiments may be practiced without one or more of these specific details, or with other methods, components, materials, etc. In other instances, well-known structures associated with ultrasound medical devices and electrocardiogram sensors have not been shown or described in detail to avoid unnecessarily obscuring descriptions of the embodiments. 
     Unless the context requires otherwise, throughout the specification and claims that follow, the word “comprise” and variations thereof, such as, “comprises” and “comprising” are to be construed in an open, inclusive sense that is as “including, but not limited to.” Further, the terms “first,” “second,” and similar indicators of sequence are to be construed as interchangeable unless the context clearly dictates otherwise. 
     Reference throughout this specification to “one embodiment” or “an embodiment” means 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 are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. 
     As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the content clearly dictates otherwise. It should also be noted that the term “or” is generally employed in its broadest sense that is as meaning “and/or” unless the content clearly dictates otherwise. 
     Further, the break lines in the drawings are used to indicate that there are more elements present but are omitted for the sake of simplicity. 
     Frequently used methods of diagnosis in medicine for physiological assessment, e.g., of the cardiothoracic cavity, include sonography, auscultation, and electrocardiography. These methods of diagnosis provide different kinds of information usable to assess the anatomy and physiology of the organs present in a region of interest, e.g., the cardiothoracic cavity. 
     Medical ultrasound imaging (sonography) has been one of the most effective methods for examining both the heart and the lungs. Ultrasound imaging provides anatomical information of the heart as well as qualitative and quantitative information on blood flow through valves and main arteries such as the aorta and pulmonary artery. One significant advantage of ultrasound imaging is that, with its high frame rate, it can provide dynamic anatomical and blood flow information, which is vital for assessing the condition of the heart, which is always in motion. Combined with providing blood flow information, ultrasound imaging provides one of the best available tools for assessing the structure and function of heart chambers, valves, and arteries/veins. Similarly, ultrasound imaging can assess fluid status in the body and is the best tool in assessing pericardial effusion (fluid around the heart). 
     In the case of lungs, ultrasound imaging provides information on the anatomical structure of the lungs with the ability to show specific imaging patterns associated with various lung diseases and with an ability to assess fluid status around the lung and within individual compartments of the lung including the assessment of pericardial effusion. 
     Auscultation allows for assessing the physiological condition and function of organs such as the heart and lungs by capturing audible sounds that are produced by or otherwise associated with these organs. The condition and function of these organs, or other organs as the case may be, can be evaluated based on clinical information indicating how different sounds are associated with various physiological phenomena and how the sounds change for each pathological condition. 
     Electrocardiography (ECG) is focused on the heart by capturing the electrical activity of the heart as it is related to the various phases of the cardiac cycle. The condition and function of the heart may be evaluated based on clinical knowledge indicating how the electrical activity of the heart changes based on various pathological conditions. 
     In order to sense the above mentioned physiological data of a patient, some medical sensing devices incorporate various sensors in one device to conveniently detect multiple data at the same time. Some devices are capable of detecting both ultrasound data and ECG data using the same device. For example, in various embodiments provided herein, an ultrasound device may include one or more ECG leads spaced apart from an ultrasound sensor on a sensor face of the device. In conventional ultrasound imaging, an ultrasound transmission gel or ultrasound gel is typically applied to the sensor or the patient to enhance reception of ultrasound signals. However, since ultrasound gels are typically electrically conductive water-based gels, such ultrasound gels could electrically connect or short circuit the ECG leads in devices having ECG leads arranged on or near the sensor face. When this occurs, the ECG data cannot be acquired correctly and the signals are likely to have noise or sometimes no signal at all. 
     The present disclosure provides devices and methods in which ultrasound and ECG signals may be acquired by a single handheld device that does not utilize any ultrasound sensing gels. 
       FIG. 1  is a perspective view illustrating a device  100  having an ultrasound sensor, an electrocardiogram sensor, and an acoustic coupling pad, in accordance with one or more embodiments of the present disclosure. 
     The device  100  can be connected to another device having a display screen to display relevant data acquired from diagnosing a patient. In some embodiments, the device  100  may include various circuitries, such as microprocessors, signal/data processing circuitry, etc., to process the acquired information (e.g., physiological data including ultrasound data or electrocardiography data of a patient). Additionally, or alternatively, the device  100  may transmit the acquired physiological data of the patient to another device for processing the data acquired by the device  100 . These connected devices may include microprocessors, various signal/data processing circuitries, or the like to process the physiological data of the patient. For example, the connected electronic device may include, but is not limited to, mobile phones, handheld devices, a personal computer (PC), notebook computers, laptops, tablet PCs, and any other devices capable of data processing. 
     In operation, a user may place the sensor face  130  of the device  100  in a desired location on a patient&#39;s body. Once suitably positioned, the device  100  may be operated to acquire signals using one or more sensors on the sensor face  130 , such as auscultation sensors (not shown), ECG sensors (not shown), and ultrasound sensors (not shown). In some embodiments, the signals acquired from one or more of the auscultation sensors, the ECG sensors, and the ultrasound sensors may be simultaneously acquired and synchronized with one another. With various sensors positioned on the sensor face  130 , the device  100  may be utilized to obtain various physiological data with one scan of a target area or region of the patient. 
     The device  100  may include a housing  105  that forms an exterior of the device  100 . The housing  105  may house any microprocessors, for example, signal processing circuitry, data processing circuitry, digital signal processors (DSP) for digital signal processing, and various sensors for sensing physiological data of the patient. In some embodiments, the housing  105  may include a pad portion  110 , a sensor portion  112  and handle portion  114 . 
     The pad portion  110  is near a first end  118  of the housing  105 . The first end  118  is proximate to the sensor face  130 , which will be in contact with the patient during use of the device  110 . The second end  122  is at an opposite side of the housing  105  than the first end  118 . The handle portion  114  is between the first end  118  and the second end  122  of the housing  105  to provide a convenient grip for the person using the device  100 . The sensor portion  112  is between the pad portion  110  and the handle portion  114 . The sensor portion  112  includes various sensors for acquiring physiological data from the patient. For example, the sensor portion  112  may include ECG sensors for acquiring electrocardiography data of the patient. The sensor portion  112  may also include ultrasound sensors for acquiring ultrasound data. In addition, the sensor portion  112  may include auscultation sensors for acquiring auscultation data. In  FIG. 1 , the handle portion  114  is shown as being positioned between the second end  122  and the sensor portion  112 . However, in different embodiments, the location of the sensor portion  112  and the handle portion  114  can change according to design needs or objectives and does not necessarily have to be fixed at certain locations. 
     The pad portion  110  extends outwardly from the first end  118  of the housing  105  and the sensor portion  112 . The pad portion  110  is generally located close to the first end  118  so that the pad portion  110  may directly contact the skin surface of the patient during use of the device  100 . For example, one side of the pad portion  110  is in direct contact with the sensor portion  112  and the other side may be in direct contact with the patient. It will be explained later on in detail that this pad portion  110  having an acoustic coupling pad  116  may serve as a replacement for conventional ultrasound gels, which are typically water-based gels to transfer the acquired acoustic signals with low or no acoustic loss. 
     The handle portion  114  is a portion of the housing  105  that is gripped by a user to hold, control, and manipulate the device  100  during use. The handle portion  114  may include gripping features, such as one or more detents  120 , and in some embodiments, the handle portion  114  may have a same general shape as portions of the housing  105  that are distal to, or proximal to, the handle portion  114 . In general, the handle portion  114  refers to a portion of the housing  105  that is located between the sensor portion  112  and the second end  122  of the housing  105 , which will be described in further detail later herein. 
     In some embodiments, the housing  105  may further surround internal electronic components and/or circuitry of the device  100 , including, for example, electronics such as driving circuitry, oscillators, beamforming circuitry, filtering circuitry, and the like. The housing  105  may be formed to surround or at least partially surround externally located portions of the device  100 , such as the sensor face  130 , and the housing  105  may be a sealed housing, such that moisture, liquid or other fluids are prevented from entering the housing  105 . The housing  105  may be formed of any suitable materials, and in some embodiments, the housing  105  is formed of a plastic material. The housing  105  may be formed of a single piece (e.g., a single material that is molded surrounding the internal components) or may be formed of two or more pieces (e.g., upper and lower halves) which are bonded or otherwise attached to one another. 
     The pad portion  110  may include an acoustic coupling pad  116  that is placed on a portion of the sensor face  130 . The acoustic coupling pad  116  may be positioned to partially cover the sensor face  130 , such that the sensors located near the sensor face  130  are spaced apart from and do not directly contact the patient (e.g., the patient&#39;s skin) during use of the device  100 . For example, instead of the sensor face  130  directly contacting the patient&#39;s skin, the acoustic coupling pad  116  placed in between the patient and the sensor face  130  can acoustically couple the patient (more specifically the body part of the patient that is being imaged by the device) with the device  100  during use. The acoustic coupling pad  116  may serve as an acoustic pathway for physiological signals to be transmitted and received by the ultrasound sensor of the device  100  during use. While the acoustic coupling pad  116  may separate the sensor face  130  from the patient&#39;s body by a small distance, the various physiological signals may be effectively transmitted and received via the acoustic coupling pad  116  to the sensor portion  112  due to the acoustic pathway provided by the acoustic coupling pad  116 . The features of the acoustic coupling pad  116  and the various components within the sensor portion  112  will be described in further detail later herein. 
       FIG. 2  is an enlarged perspective view  200  of the sensor portion  112  of the device  100  shown in  FIG. 1 .  FIG. 2  shows the sensor portion  112  with the acoustic coupling pad  116  being detached from the sensor face  130  for illustration purposes for describing the components of the sensor portion  112  of the device  100 . The sensor portion  112  of the device  100  includes an ultrasound sensor  210 . In some embodiments, the sensor portion  112  includes a plurality of ECG electrodes  220   a ,  220   b ,  220   c  (which may be referred to collectively as an ECG sensor  220 ) positioned at various locations spaced apart from the ultrasound sensor  210 . Any number of ECG electrodes may be included in the sensor portion  112 , for example, in some embodiments the sensor portion  112  may include more than 3 ECG electrodes. 
     In some embodiments, the sensor portion  112  may include one or more auscultation sensors  240 , e.g., a first auscultation sensor positioned near or beneath a first membrane  262  and a second auscultation sensor positioned near or beneath a second membrane  264 . Each of the ultrasound sensor  210 , the auscultation sensors  240 , and the ECG sensor  220  is positioned adjacent to the sensor face  130  of the device  100 . In use, the sensor face  130  may be placed near or in contact with a patient&#39;s skin, and the device  100  may obtain ultrasound, auscultation signals, and ECG signals via the ultrasound sensor  210 , the auscultation sensors  240 , and the ECG sensor  220 , respectively. In some embodiments, there may be additional, various kinds of sensors incorporated in the sensor portion  112  of the device  100  to sense different physiological data according to various medical needs, and the sensors included in embodiments of the present disclosure are not limited to ultrasound sensors, auscultation sensors, and ECG sensors. 
     As shown in  FIGS. 1 and 2 , in some embodiments, the device  100  includes auscultation sensors  240  adjacent to the ultrasound sensor  210  at the sensor face  130 . The auscultation sensors  240  may be any sensors operable to detect internal body sounds of a patient, including, for example, body sounds associated with the circulatory, respiratory, and gastrointestinal systems. That is, target sounds such as heart sounds of a patient may be sensed by the auscultation sensors  240 . In one embodiment, the auscultation sensors  240  may be microphones. In some embodiments, the auscultation sensors  240  may be electronic or digital stethoscopes, and may include or otherwise be electrically coupled to amplification and signal processing circuitry for amplifying and processing sensed signals, as may be known in the relevant field. In another embodiment, the first auscultation sensor positioned near the first membrane  262  and the second auscultation sensor positioned near the second membrane  264  may be two identical auscultation sensors. However, in some embodiments, the device  100  may employ different kinds of auscultation sensors and the auscultation sensors may be different from one another. 
     The ultrasound sensor  210  includes an ultrasound array or ultrasound transducer  440  (see  FIG. 4 ) configured to transmit an ultrasound signal toward a target structure in a region of interest (ROI) of the patient. The transducer  440  is further configured to receive echo signals returning from the target structure in response to transmission of the ultrasound signal. To that end, the transducer  440  may include transducer elements that are capable of transmitting an ultrasound signal and receiving subsequent echo signals. In various embodiments, the transducer elements may be arranged as elements of a phased array (not shown). Suitable phased array transducers are known in the art. 
     The transducer  440  of the ultrasound sensors  210  may be a one-dimensional (1D) array or a two-dimensional (2D) array of transducer elements. The transducer array may include piezoelectric ceramics, such as lead zirconate titanate (PZT), or may be based on microelectromechanical systems (MEMS). For example, in various embodiments, the ultrasound sensors  210  may include piezoelectric micromachined ultrasonic transducers (PMUT), which are microelectromechanical systems (MEMS)-based piezoelectric ultrasonic transducers, or the ultrasound sensor  210  may include capacitive micromachined ultrasound transducers (CMUT) in which the energy transduction is provided due to a change in capacitance. 
     The ultrasound sensor  210  may further include an ultrasound focusing lens  450  (see  FIG. 4 ), which is positioned distally with respect to the ultrasound transducer  440 , and which may form a part of the sensor face  130 . The acoustic coupling pad  116  may be disposed on the ultrasound focusing lens  450  and may replace the conventional water-based ultrasound gels which may cause the ECG electrodes  220   a ,  220   b ,  220   c  to be electrically connected to each other. This will be explained in more detail in relation with  FIG. 3 . The focusing lens  450  may be any lens operable to focus a transmitted ultrasound beam from the ultrasound transducer  440  toward a patient and/or to focus a reflected ultrasound beam from the patient to the transducer  440 . The ultrasound focusing lens  450  may have a substantially flat shape as shown in  FIG. 4 . In some embodiments, the ultrasound focusing lens  450  may have a front surface that is substantially coplanar with the first membrane  262  and the second membrane  264 . However, in other embodiments, the ultrasound focusing lens  450  may have a curved surface shape, or an oval shape. That is, the ultrasound focusing lens  450  may have different shapes depending on a desired application, e.g., a desired operating frequency, or the like. The ultrasound focusing lens  450  may be formed of any suitable material, and in some embodiments, the ultrasound focusing lens  450  is formed of a room-temperature-vulcanizing (RTV) rubber material. 
     The ECG sensor  220  may be any sensor that detects electrical activity, e.g., of a patient&#39;s heart, as may be known in the relevant field. For example, the ECG sensor  220  may include any number of ECG electrodes  220   a ,  220   b ,  220   c , which in operation are placed in contact with a patient&#39;s skin and are used to detect electrical changes in the patient that are due to the heart muscle&#39;s pattern of depolarizing and repolarizing during each heartbeat. 
     As shown in  FIG. 2 , the ECG sensor  220  may include a first electrode  220   a  that is positioned adjacent to a first side of the ultrasound sensor  210  (e.g., adjacent to the left side of the ultrasound sensor  210  which may correspond to the location where the first membrane  262  is positioned), and a second electrode  220   b  that is positioned adjacent to a second side of the ultrasound sensor  210  that is opposite to the first side (e.g., adjacent to the right side of the ultrasound sensor  210  which may correspond to the location where the second membrane  264  is positioned). The ECG sensor  220  may further include a third electrode  220   c  that is positioned adjacent to a third side of the ultrasound sensor  210  (e.g., adjacent to the lower side of the ultrasound sensors  210  which is located between the first membrane  262  and the second membrane  264 ). This third side may extend between the first side and the second side, and a membrane adjacent to the third side may also be referred to as the third membrane (not shown). In some embodiments, the third electrode  220   c  may be exposed through the third membrane and the first and second electrodes  220   a  and  220   b  may be exposed through the first and second membrane  262 ,  264  respectively. In some embodiments, each of the first, second, and third ECG electrodes  220   a ,  220   b ,  220   c  have different polarities. For example, the first ECG electrode  220   a  may be a positive (+) electrode, the second ECG electrode  220   b  may be a negative (−) electrode, and the third ECG electrode  220   c  may be a ground electrode. 
     The number and positions of the ECG sensor electrodes  220  may vary in different embodiments. As shown in  FIG. 2 , the ECG electrodes  220   a ,  220   b ,  220   c  may be approximately equidistant from one another. The first and second ECG electrodes  220   a ,  220   b  may be positioned near a top edge of the sensor face  130 , while the third ECG electrode  220   c  may be positioned between the lower side of the ultrasound sensor  210  and a bottom edge of the sensor face  130 . In other embodiments, the ECG electrodes  220   a ,  220   b ,  220   c  the spacing between and the individual locations of the ECG electrodes  220   a ,  220   b ,  220   c  may be differently placed based on design needs. 
     In some embodiments, the ultrasound sensor  210 , the ECG sensor  220 , or the auscultation sensors  240  may be located differently than as shown in  FIG. 2 . The various sensors may be located adjacent to each other to effectively obtain the patient&#39;s physiological data but the individual sensor components can be placed in a different pattern or location. For example, depending on the specific part of the patient that is being diagnosed and according to other various medical needs, the device  100  can have auscultation sensors located only on or beneath the first membrane  262 , and the ECG sensor  220  located only on or beneath the second membrane  264 . In some embodiments, the ultrasound sensor  210  may be located near a first side area of the sensor face, with the auscultation sensors  240  located in the center area of the sensor face  130 , and the ECG sensor  220  located near a second side of the sensor face opposite the first side. The ultrasound sensor  210 , the auscultation sensors  240 , and the ECG sensors  220  may be positioned in any suitable arrangement on or adjacent the sensor face  130 , and embodiments provided herein are not limited to the arrangement shown in  FIG. 2 . 
     In some embodiments, first and second membranes  262 ,  264  are positioned adjacent to opposite sides of the ultrasound sensor  210  and may form a part of the sensor face  130 . The first and second membranes  262 ,  264  may be formed of any suitable material, and in one embodiment, the first and second membranes  262 ,  264  are formed of a room-temperature-vulcanizing (RTV) rubber material. In some embodiments, the first and second membranes  262 ,  264  are formed of a same material as the ultrasound focusing lens  450 . 
     In some embodiments, the sensor face  130  includes a sealant which seals the sensor face  130  of the device  100  so that it is compliant with ingress protection specifications of IPX7 of the IP Code (as published by the International Electrotechnical Commission) (e.g., it is liquid tight when submerged to a depth of at least one meter). The sealant may be provided, for example, between the membranes  262 ,  264  and the respective sides of the ultrasound sensor  210 , and/or between the ultrasound sensor  210 , the membranes  262 ,  264  and the side surfaces of the housing  105 . In some embodiments, the sealant is provided over the ultrasound focusing lens  450  of the ultrasound sensor  210  and the membranes  262 ,  264 . In such embodiments, the acoustic coupling pad  116  may be overlain on top of the sealant overlapping the face of the ultrasound focusing lens  450  of the ultrasound sensor  210 . The sealant may be a RTV rubber material, and in some embodiments, the sealant may be formed of a same material as the ultrasound focusing lens  450  and/or the first and second membranes  262 ,  264 . 
       FIG. 3  is an enlarged perspective view  300  of the pad portion  110  and the sensor portion  112  of the device  100  shown in  FIG. 1 , in accordance with one or more embodiments. Since most of the common elements were explained in detail in relation to  FIG. 2 , descriptions of previously explained elements will be omitted and the following description of  FIG. 3  will focus on the features related to the pad portion  110  and the acoustic coupling pad  116 . 
     As shown in  FIG. 3 , the pad portion  110  includes an acoustic coupling pad  116 . The acoustic coupling pad  116  is positioned on the ultrasound focusing lens  450  of the ultrasound sensor  210 . In one embodiment, the size (e.g., length and width) of the acoustic coupling pad  116  may match the size (e.g., length and width) of the ultrasound focusing lens  450  and the acoustic coupling pad  116  may be disposed on top of the lens  450 . In some embodiments, the size of the acoustic coupling pad  116  may be smaller than the size of the ultrasound focusing lens  450 , for example, such that the acoustic coupling pad  116  only partially covers the ultrasound focusing lens  450 . In other embodiments, the size of the acoustic coupling pad  116  may be larger than the size of the ultrasound focusing lens  450 , for example, such that the acoustic coupling pad  117  completely overlaps the ultrasound focusing lens  450  with portions of the acoustic coupling pad  116  extending laterally beyond side edges of the ultrasound focusing lens  450 . The acoustic coupling pad  116  may have any shape or size, which may be determined based on the design needs or medical applications of the acoustic coupling pad  116  and the device  100 , but will have a suitable size to provide the function of serving as an acoustic pathway for the ultrasound sensor  210 . In some embodiments, the acoustic coupling pad  116  may have a suitable size to cover the ultrasound focusing lens  450 , while being spaced apart from the plurality of ECG electrodes  220   a ,  220   b , and  220   c  thereby preventing short circuits of the ECG electrodes  220   a ,  220   b , and  220   c  through the acoustic coupling pad  116 . Electrical shorts between ECG electrode leads will result in little to no ECG signals, and the size of the acoustic coupling pad  116  may be designed to not cause the short between the ECG electrode leads. This will be explained in more detail later. 
     The device  100  is a multifunctional device that is capable of acquiring different types of data, such as ultrasound data, auscultation data, and electrocardiography data, at the same time. The device  100  achieves this by placing various sensors (e.g., ultrasound sensor, ECG sensor, auscultation sensors) in the sensor portion  112  of the device  100 . However, by placing ECG electrode leads  220   a ,  220   b ,  220   c  on the same surface as the ultrasound sensor  210 , when the water-based ultrasound scanning gels are used for ultrasound scanning, the water-based gels may electrically connect between one or more ECG electrode leads. These unwanted connections between the ECG electrode leads  220   a ,  220   b ,  220   c  through the scanning gels causes the ECG signals to have noise or possibly produce unclear and incorrect ECG signals. These unclear ECG signals collected from the patient can prevent the medical practitioner from correctly diagnosing the patient based on the acquired signals. Therefore, in utilizing the device  100 , the technical problem raised from using the water-based ultrasound scanning gels is overcome due to the presence of the acoustic coupling pad  116 . 
     The proposed acoustic coupling pad  116  which serves as a replacement for the water-based gel for the ultrasound sensor  210  is placed on the ultrasound focusing lens  450  and spaced apart from the plurality of ECG electrodes  220   a ,  220   b ,  220   c . In one embodiment, the plurality of ECG electrodes  220   a ,  220   b ,  220   c  may be disposed on the sensor face  130  and the acoustic coupling pad  116  may be placed in a location that does not electrically connect the respective ECG electrodes  220   a ,  220   b ,  220   c  with each other. By placing the acoustic coupling pad  116  over the ultrasound focusing lens  450  while spacing the acoustic coupling pad  116  away from the plurality of ECG electrodes  220   a ,  220   b ,  220   c , the positional relationship ensures that the ECG electrodes will not be electrically connected to each other. Also at the same time, the acoustic coupling pad  116  may provide the ultrasound sensor  210  with an acoustic pathway for improving the reception of ultrasound data of the patient. The acoustic coupling pad  116  eliminates the air gap that may be formed between the ultrasound sensors  210  and the patient&#39;s skin and transfers ultrasound signals with minimum or reduced acoustic loss. 
     In some embodiments, the acoustic coupling pad  116  may have properties for providing adequate ultrasound coupling. These properties ensure that the ultrasound signals from the patient will be properly obtained from the acoustic coupling pad  116  to the ultrasound sensor  210  with high quality ultrasound image. In one embodiment, the acoustic coupling pad  116  may be an acoustically transparent silicone gel pad. For example, the acoustically transparent silicone gel pad has shown promising results of increasing ultrasound sensitivity as compared to the ultrasound gels and eliminated the need to use ultrasound gels. In some embodiments, synthetic rubber may be used in forming the acoustic coupling pad  116 . The synthetic rubber may include substances such as cis-1,4-polybutadiene for the acoustic coupling pad  116 , which has been shown to reduce acoustic loss. The acoustic coupling pad  116  formed utilizing these materials has the capability of clearly transmitting the ultrasound signals from the patient&#39;s bodily organs to the ultrasound sensor  210  of the device  100  with minimum or low acoustic loss and the device  100  is able to clearly amplify and cancel any noise from the signals to reproduce a definite ultrasound image. 
     In some embodiments, the acoustic coupling pad  116  may be formed using materials taking into account the appropriate acoustic impedance for the specific ROI of the patient to be imaged (e.g., certain tissues such as heart, kidney, liver, muscle, etc.). The acoustic impedance may be based on the density of a certain tissue and the speed of sound within that tissue. The acoustic impedance of a tissue or material such as blood, fat, liver, heart, brain, kidney, muscle, etc., may all differ. A typical density, speed of sound, and acoustic impedance values of various tissues or materials are shown in Table 1. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Examples of Typical Density, Speed of Sound, and 
               
               
                 Acoustic Impedance Values of Tissues/Materials 
               
            
           
           
               
               
               
               
               
            
               
                   
                   
                   
                 Speed of 
                 Acoustic 
               
               
                   
                 Tissue or 
                 Density 
                 Sound 
                 Impedance 
               
               
                   
                 Material 
                 (g/cm 3 ) 
                 (m/sec) 
                 [kg/(sec · m 2 )] × 10 6   
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                   
                 Water 
                 1 
                 1480 
                 1.48 
               
               
                   
                 Brain 
                 1.03 
                 1550 
                 1.60 
               
               
                   
                 Heart 
                 1.045 
                 1570 
                 1.64 
               
               
                   
                 Kidney 
                 1.05 
                 1570 
                 1.65 
               
               
                   
                 Liver 
                 1.06 
                 1590 
                 1.69 
               
               
                   
                   
               
            
           
         
       
     
     Accordingly, based on which ROI of the patient being examined, the acoustic coupling pad  116  may be variously designed so that the acoustic impedance of the acoustic coupling pad  116  is matched or is substantially similar to the acoustic impedance of tissue between the acoustic coupling pad  116  and a particular structure or organ to be imaged. 
     In general, a portion of ultrasound energy output by an ultrasound imaging device is reflected at any interface between media having different acoustic impedances. The difference in acoustic impedance between the patient&#39;s skin and the outer surface of an ultrasound imaging device which contacts the patient&#39;s skin therefore at least partially dictates how much ultrasound energy will be transmitted into and out of the patient, as well as how much of the ultrasound energy will be reflected at the interface with the patient&#39;s skin. In some embodiments, the acoustic coupling pad  116  may be formed to have an impedance that is substantially the same or similar to an impedance of human tissue, which facilitates efficient transmission of the ultrasound energy through the tissue (which may include, for example, skin, fat, water, etc.) and to a desired structure of the patient to be imaged. For example, by adjusting the ratio or amount of cis-1,4-polybutadiene in the synthetic rubber which may be utilized in the acoustic coupling pad  116 , the acoustic impedance of the acoustic coupling pad  116  may be formed to substantially match the impedance of the patient&#39;s skin, thereby reducing or minimizing undesired reflection of ultrasound energy at the interface between the acoustic coupling pad  116  and the patient&#39;s skin. This may ensure efficient transmission of the ultrasound energy through the skin and tissue, and reduce or minimize loss (e.g., reflection) of the acoustic signals as they are transmitted through the skin and tissue toward and from a particular structure or organ under diagnosis. 
     In  FIGS. 3, 4 and 5 , the acoustic coupling pad  116  has been described as being a thin rectangular pad, or a rectangular pad that has a round corner on the edges to have a cylindrical edge. However, the shape of the acoustic coupling pad  116  is not limited to these shapes and the acoustic coupling pad  116  may have various shapes according to design needs. For example, the acoustic coupling pad  116  may be of a circular pad shape, triangular shape, or polygonal shape, etc. In other embodiments, the shape of the acoustic coupling pad  116  may depend on the shape of the lens  450 . 
     In some embodiments, the acoustic coupling pad  116  may be a silicone pad or a synthetic rubber pad including cis-1,4-polybutadiene with a thickness less than 10 mm. More preferably, the acoustic coupling pad  116  may be made of a silicone pad or a synthetic rubber pad including cis-1,4-polybutadiene and may have a thickness less than 6 mm. In one embodiment, the height of the acoustic coupling pad  116  may be measured from the distance between a first surface (e.g., top surface) and a second surface (e.g., bottom surface) of the acoustic coupling pad  116 . In another embodiment, the height of the acoustic coupling pad  116  may be measured from the surface of the lens  450  in which the acoustic coupling pad  116  is disposed over to the first surface (e.g., top surface) of the acoustic coupling pad  116 . Since the human skin that will contact the acoustic coupling pad  116  is generally soft, elastic and curvy, the acoustic coupling pad  116  may be formed to have an oval shape. For example, the acoustic coupling pad  116  may be of a convex shape where the center of the top surface is protruding outwards. In this example, the height of the acoustic coupling pad  116  may be determined based on the distance between the central point of the top convex surface to the top surface of the lens  450 . On the other hand, the acoustic coupling pad  116  may be of a concave shape where the center of the top surface is protruding inwards (towards more closer to the lens  450 ). In this example, the height of the acoustic coupling pad  116  may be determined based on the distance between the central point of the top concave surface to the top surface of the lens  450 . In this particular example, due to the concave shape of the acoustic coupling pad  116 , the height in the periphery of the pad  116  will be higher than the height in the center of the pad  116 . However, in some embodiments, the height of the pad  116  may be determined based on the central point of the concave shaped pad. 
     The thickness of the acoustic coupling pad  116  needs to take into account that if the pad is too thick, it may space the ECG sensor  220  apart from the patient&#39;s skin, thereby limiting the detection of adequate ECG signals. As such, the thickness of the acoustic coupling pad  116  may be designed to ensure that the device  100 , when in use would allow the plurality of ECG electrodes  220   a ,  220   b ,  220   c  on the sensor face  130  to touch the skin of the patient. Since skin is soft and elastic, even though the ECG electrodes  220   a ,  220   b ,  220   c  may be spaced apart from the exposed surface of the acoustic coupling pad  116 , when the sensor face  130  is applied to the patient&#39;s skin with a small amount of force, the ECG electrode leads  220   a ,  220   b ,  220   c  may still contact the patient&#39;s skin, ensuring accurate measure of ECG signals. For example, with the acoustic coupling pad  116  having a thickness of 10 mm or less, the ECG electrode leads  220   a ,  220   b , and  220   c  can contact the patient&#39;s skin and can appropriately and accurately obtain ECG signals of the patient, while the acoustic coupling pad  116  also contacts the skin such that the ultrasound sensor  210  can acquire ultrasound signals/images through the acoustic coupling pad  116 . 
     An adhesive may be applied between the acoustic coupling pad  116  and the ultrasound focusing lens  450  to improve the mechanical coupling of the acoustic coupling pad  116  to the lens  450 . For example, a light adhesive may be used to couple the acoustic coupling pad  116  with the ultrasound focusing lens  450 . When the adhesive is applied at one side of the acoustic coupling pad  116  (e.g., the array or transducer side  440 ), the acoustic coupling pad  116  may cover the ultrasound focusing lens  450  or even the auscultation sensors  240 . However, the adhesive does not cover the ECG electrode leads  220   a ,  220   b ,  220   c  so that the acoustic coupling pad  116  is overlain over the ECG electrode leads  220   a ,  220   b ,  220   c  which may cause unwanted electrical short circuits. 
     The exposed side of the acoustic coupling pad  116  (e.g., the side that directly contacts the patient) may be coated with a biocompatible coating material, which may improve lubricity and coupling with the ROI of the patient. This will be explained in more detail in relation with  FIG. 5 . 
       FIG. 4  is a cross-sectional view  400  taken along the cut-line  4 - 4  of  FIG. 3 , illustrating further details of the pad portion  110  and the sensing portion  112  of the device  100 , in accordance with one or more embodiments. 
     As shown in  FIG. 4 , the first and second membranes  262 ,  264  are positioned in front of the auscultation sensors  240  and adjacent to the ultrasound focusing lens  450 . The acoustic coupling pad  116  is on the ultrasound focusing lens  450  of the ultrasound sensors  210 . In some embodiments, the auscultation sensors  240  are spaced apart from the membranes  262 ,  264  by respective gaps  410 , which may be air gaps. These air gaps may provide an acoustic tunnel for clearly receiving the auscultation data through the auscultation sensors  240 . 
     The auscultation sensors  240  may be positioned in respective auscultation sensor sockets  420 , which may fix a position of the auscultation sensors  240  so that they are spaced apart from the respective membranes  262 ,  264  by a desired gap  410 . In some embodiments, the gaps  410  have a distance within a range of about 0.5 mm to about 1.5 mm. In some embodiments, the gaps  410  have a distance of about 1 mm. In some embodiments, the auscultation sensor sockets  420  are formed as an internal piece of the housing  105 . For example, the auscultation sensor sockets  420  may be molded into the housing  105 . The auscultation sensor sockets  420  may be sized to accommodate the auscultation sensors  240 , and the auscultation sensors  240  may be securely held in the auscultation sensor sockets  420 . In some embodiments, the auscultation sensors  240  may be secured within the auscultation sensor sockets  420  by an adhesive material. 
     The auscultation sensor sockets  420  may fasten or affix the auscultation sensors  240  to the housing  105  so that it impedes any movement of the auscultation sensors  240  in any direction. If there is a room or gap between the auscultation sensor sockets  420  and the auscultation sensors  240 , this room or gap may create unnecessary noises that are irrelevant to the physiological signals or sounds of the patient. The fixed position of the auscultation sensors  240  eliminates any movements so that the auscultation sensors  240  can clearly obtain the physiological signals or sounds of the patient during use. 
     In addition, in some embodiments, with the auscultation sensors  240  positioned in the auscultation sensor sockets  420  and spaced apart from the membranes  262 ,  264  by a desired gap  410 , the membranes  262 ,  264  may operate as diaphragms which convert mechanical vibrations (e.g., from motion against the membranes  262 ,  264  and/or in response to receiving acoustic vibrations) into sounds which are detectable by the auscultation sensors  240 . 
     In one embodiment, the first and second membranes  262 ,  264  are positioned adjacent to opposite sides of the ultrasound sensor  210  and may form a part of the sensor face  130 . The first and second membranes  262 ,  264  may be formed of any suitable material, and in one embodiment, the first and second membranes  262 ,  264  are formed of a room-temperature-vulcanizing (RTV) rubber material. In some embodiments, the first and second membranes  262 ,  264  are formed of a same material as the ultrasound focusing lens  450 . 
     In some embodiments, the ultrasound focusing lens  450  may be substantially coplanar with the first membrane  262  and the second membrane  264 . By positioning the ultrasound focusing lens  450  in the same plane as the first and second membrane  262 ,  264 , the distance between the ECG electrode leads  220   a ,  220   b ,  220   c  also positioned on the first and second membrane  262 ,  264  and the patient&#39;s skin can be maintained at a desired, suitable distance even after the acoustic coupling pad  116  is attached to the ultrasound focusing lens  450 . If the distance between the outer surface of the acoustic coupling pad  116  that is in contact with the patient&#39;s skin and the plane of lens  450  (which may be coplanar with the first and second membrane  262 ,  264 ) is spaced apart beyond a suitable distance, the ECG electrode leads  220   a ,  220   b ,  220   c  may not directly contact the patient&#39;s skin which may prevent the leads from effectively receiving ECG data. 
     In other embodiments, the ultrasound focusing lens  450  may be placed to so that the acoustic coupling pad  116  may be substantially coplanar with the first membrane  262  and the second membrane  264 . By placing the ultrasound focusing lens  450  so that the acoustic coupling pad  116  is in the same plane as the first and second membranes  262 ,  264 , the ECG electrode leads  220   a ,  220   b ,  220   c  and the acoustic coupling pad  116  may directly contact the patient&#39;s skin without applying any additional force to reduce a gap between the ECG electrode leads  220   a ,  220   b ,  220   c  and the patient&#39;s skin. This configuration may increase the quality of the ECG data received from the ECG electrode leads  220   a ,  220   b ,  220   c  since there will be no air gap between the leads  220   a ,  220   b ,  220   c  and the patient&#39;s skin. The ultrasound focusing lens  450  may be recessed in a direction towards the ultrasound transducer  440  which may decrease the space between the lens  450  and the transducer  440 . For example, the ultrasound focusing lens  450  may be recessed with respect to the membranes  262 ,  264  by a distance that is about the same as the thickness of the acoustic coupling pad  116 . In one embodiment, the acoustic coupling pad may have a thickness of about 5 mm. In this embodiment, the lens  450  may be recessed with respect to outer or exposed surfaces of the membranes  262 ,  264  by a distance of about 5 mm. When the acoustic coupling pad  116  is attached to the lens  450 , the outer surface of the acoustic coupling pad  116  may be substantially coplanar with the outer surfaces of the first and second membranes  262 ,  264  and the ECG electrode leads  220   a ,  220   b ,  220   c  may directly contact the patient&#39;s skin to provide improved acquisition of ECG data. While providing an entirely coplanar surface at the sensor face  130  may be beneficial in the reception of the patient&#39;s physiological data, due to the soft and cushion-like surface of the human skin, in some embodiments, the impact of the spaced distance between the plane of the membranes  262 ,  264  and the acoustic coupling pad  116  may have minimum impact on the quality of the ECG data received through the ECG electrode leads  220   a ,  220   b ,  220   c.    
       FIG. 5  is a perspective view  500  of an acoustic coupling pad  116 , in accordance with one or more embodiments. 
     As shown in  FIG. 5 , an acoustic coupling pad  116  is placed on a backing  510 . The backing  510  is adhered to a first surface (e.g., a surface that directly faces and contacts the backing  510 ) of the acoustic coupling pad  116  with an adhesive material. The adhesive material may remain on the acoustic coupling pad  116  as an adhesive layer after the acoustic coupling pad  116  is peeled off from the backing  510 . The adhesive material forms a film-like thin adhesive layer on the first surface of the acoustic coupling pad  116  and this material may be any suitable material that can enhance the mechanical or physical coupling between the ultrasound focusing lens  450  and the acoustic coupling pad  116 . That is, the backing  510  may leave adhesives on the first surface of the acoustic coupling pad  116  that can be easily attached with the ultrasound focusing lens  450  which is formed of a room-temperature-vulcanizing (RTV) rubber material. In addition, these adhesive materials may be any suitable materials having characteristics that are strong enough to be coupled with the lens  450  but is capable of being easily peeled off by a medical practitioner after use or after the diagnosis is completed. Some examples of adhesive materials which may be provided on the first surface of the acoustic coupling pad  116  may include, but is not limited to, tape, paste, glue, or any other suitable material. 
     The acoustic coupling pad  116  includes a second surface  520 , that is opposite of the first surface. In some embodiments, the second surface  520  may be parallel to the first surface. However, in other embodiments, depending on the shape of the acoustic coupling pad  116 , the second surface  520  is not necessarily parallel to the first surface and the second surface  520  may have a curvature depending on the various application and design needs of the acoustic coupling pads. For example, while the first surface may have a flat surface to improve the adhesion with the lens  450 , the second surface  520  may have a wave-shape surface to improve smoothness or lubricity with the patient&#39;s skin during ultrasound imaging. 
     The second surface  520  directly contacts the patient or the patient&#39;s skin during use of the device  100 . When the device  100  is in use, the second surface  520  contacts the skin or surface of the region that is to be diagnosed or imaged. The second surface  520  of the acoustic coupling pad  116  may be coated with a biocompatible coating, which may be a coating of any biocompatible material which is compatible with living tissue and which does not produce a toxic or immunological response when exposed to the body. Moreover, the biocompatible coating may decrease friction between the acoustic coupling pad  116  and the patient&#39;s skin. The biocompatible coating may be provided as a thin film-like layer on the second surface  520  of the acoustic coupling pad  116 . In one embodiment, the biocompatible coating is provided to improve lubricity of the acoustic coupling pad  116 . Biocompatible coatings may include substances having smooth and slippery oil-like materials. These biocompatible coatings normally do not have any impact or effect that will alter or change the physiological data (e.g., ultrasound data). That is, the ultrasound data received through the ultrasound sensor  210  may not be affected by the biocompatible coating applied on the second surface  520  of the acoustic coupling pad  116 . The biocompatible coating may be a medical grade coating that serves as an acoustic channel that will easily pass through any ultrasound signals to and from the ultrasound transducers  440 . The biocompatible coating is capable of relaying the ultrasound signals with minimum acoustic loss or no acoustic loss. In other embodiments, the biocompatible coating may have hydrophilic characteristics. In another embodiment, the biocompatible coating may have abrasion resistant characteristics. For example, the biocompatible coating may include any bio-coating material that is IEC10993 compliant. Further examples may include, but are not limited to, silicone-based biocompatible materials, biocompatible polymers, synthetic polymers, phenolic resin and the like. 
     In some embodiments, as long as the acoustic coupling pad  116  has a shape to provide the lens  450  of the ultrasound sensors  210  with a non acoustic-loss pathway, the acoustic coupling pad  116  may be of a circular pad shape, triangular shape, or polygonal shape, etc. In other embodiments, the shape of the acoustic coupling pad  116  may depend on the shape of the lens  450  and the area that the acoustic coupling pad  116  needs to cover. In some embodiments, the bottom surface of the acoustic coupling pad  116  (e.g., the first surface) may be a flat surface and the top surface of the acoustic coupling pad  116  (e.g., the second surface  520 ) may be a wave-shaped or wavy surface. The acoustic coupling pad  116  may have various shapes and sizes depending on the application and the design needed. 
     In one embodiment, the acoustic coupling pad  116  is a silicone pad. For example, this silicone pad may be a silicone that is IEC10993 compliant. However, the acoustic coupling pad  116  is not limited to these silicone pads. In other embodiments, the acoustic coupling pad  116  may be a synthetic rubber pad including cis-1,4-polybutadiene. In some embodiments, the acoustic coupling pad  116  may be formed with any material that has characteristics of minimum or low acoustic loss which is capable of relaying the ultrasound signals to produce a quality ultrasound image. 
     The thickness of the acoustic coupling pad  116  can be manufactured to have a thickness less than 10 mm. More preferably, the acoustic coupling pad  116  may have a thickness less than 6 mm. In one embodiment, the thickness of the acoustic coupling pad  116  may be measured from a distance between the first surface (e.g., the surface adhered to the backing  510 ) and the second surface  520  of the acoustic coupling pad  116 . In use, the acoustic coupling pad  116  may contact human skin, which is generally soft, elastic and curvy. Accordingly, the acoustic coupling pad  116  may be formed to have an oval shape. For example, the acoustic coupling pad  116  may be of a convex shape where the center of the second surface  520  is protruding outwards (direction opposite of the backing  510 ). In this example, the height of the acoustic coupling pad  116  may be determined based on the distance between the central point (or the highest point) of the top convex surface (e.g., second surface  520  with a convex surface) to the surface of backing  510 . On the other hand, the acoustic coupling pad  116  may be of a concave shape where the center of the second surface  520  is protruding inwards (direction towards the backing  510 ). In this example, the height or the thickness of the acoustic coupling pad  116  may be determined based on the distance between the central point (or the lowest point) of the top concave surface (e.g., second surface  520  with a concave surface) to the surface of the backing  510 . In this particular example, due to the concave shape of the acoustic coupling pad  116 , the thickness in the periphery of the pad  116  will be thicker than that in the center of the pad  116 . Based on various needs, the thickness of the pad  116  may be determined based on multiple points of the concave shaped pad or other shaped pads. 
     In some embodiments, the acoustic coupling pad  116  may be labeled with a radio-frequency identification tag (RFID) to ensure that the acoustic coupling pad  116  is not used multiple times. The RFID tag attached to the acoustic coupling pad  116  may use electromagnetic fields to easily and automatically identify and track the use of the acoustic coupling pad  116 . The RFID tags attached contain electronically stored information. Examples of electronically stored information may include information indicating when the acoustic coupling pad  116  was first manufactured, whether the acoustic coupling pad  116  has been used before or not, the location (e.g., hospital or other medical organization) where the pad  116  was used, and which medical practitioner used the acoustic coupling pad  116  to diagnose a patient, etc. The RFID tag may be provided on any surface of the acoustic coupling pad  116 , or may be embedded within the acoustic coupling pad  116 . The RFID tag can be provided in any suitable location in the acoustic coupling pad  116  which does not affect or otherwise impede the transmission of the ultrasound signals. For example, the RFID tag may be located in a side surface of the acoustic coupling pad  116  or in the bottom surface of the acoustic coupling pad  116  to not hinder the transfer of ultrasound signals to and from the transducers  440 . In other embodiments, a barcode may be used in place of RFID tags. In further embodiments, any form of codes, identification tags capable of being read by a machine-readable and utilizes encoded or encrypted symbols may be used and the sources for identifying is not necessarily limited to barcodes and RFID tags. 
     The various embodiments described above can be combined to provide further embodiments. All of the U.S. patent applications referred to in this specification and/or listed in the Application Data Sheet are incorporated herein by reference, in their entirety. Aspects of the embodiments can be modified, if necessary to employ concepts of the various patents, applications and publications to provide yet further embodiments. 
     These and other changes can be made to the embodiments in light of the above-detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure.