Abstract:
A specialized ultrasound machine tailored for use by traditional birth attendants provides an ultrasound transducer configuration adapted to work with the traditional sweeping motion of the attendant&#39;s hands over the patient&#39;s abdomen. Automatic analysis of various obstetrical conditions is performed without the need for the user to view or interpret standard ultrasound images. This machine analysis is used to provide real-time guidance in the acquisition of data by the user greatly reducing the required operator skill.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. provisional application 62/187,079 filed Jun. 30, 2015, and hereby incorporated by reference in its entirety. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     BACKGROUND OF THE INVENTION 
       [0002]    The present invention relates to medical imaging equipment and in particular to ultrasound equipment adapted for use by operators untrained in conventional imaging. 
         [0003]    Despite significant global effort mothers and newborns continue to die from preventable causes. One common example is hemorrhage from poor uterine tone due to obstructed labor (from fetal malpresentation, multiple gestation, etc.) or placenta over the cervix (placenta pies la) A quick ultrasound exam establishes fetal presentation, number, size (gestational age), and placental location. Therefore, in high-income countries where the standard of pregnancy care includes at least one ultrasound exam, these potentially life-threatening situations are rarely a surprise. 
         [0004]    In low- and middle-income countries, however, where both ultrasound systems and personnel trained in image acquisition and interpretation ate a rarity, these conditions can be extremely dangerous. In such places, a simple diagnostic tool that is easily operated by the untrained user at the point of care could be literally life-saving. An example of a low-income country is Bangladesh, where most deliveries in rural areas (˜2/3) are attended by unskilled traditional birth attendants (TBAs, called Dais), and most of the others by (typically minimally skilled) nurses or midwives. Even in areas where skilled care is available, Dais are often preferred by rural women because they reside in the community, and are part of its social and cultural matrix. For this reason in the 1970s-90s the World Health Organization focused on training TBAs, but this practice has been abandoned because ultimately it had no effect on maternal death and minimal effect on peritneonatal death. Reasons include the lack of imaging equipment; even the best trained providers cannot look inside the uterus without an appropriate device. 
         [0005]    Technology that allows users untrained in ultrasound diagnostics to make point-of-care decisions would, in fact, be useful any place in the world where there is not immediate access to an ultrasound system and provider trained in its use; examples of this in the U.S.A. include places where rapid decisions are needed to provide optimal care, such as the site of an motor vehicle accident where emergency medical technicians must evaluate a pregnant woman, or a rural labor and delivery unit where nurses, but not radiology personnel, are in house. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention provides a medical imaging machine that is ultrasound-based and specifically tailored to unskilled users and their familiar practices and capabilities. The present invention may employ an ultrasound transducer redesigned to work better with the sweeping motion commonly used by obstetrical providers for assessing pain, fundal height, and fetal position. In addition, real-time guidance can be provided with respect to manipulation of the ultrasound transducer to obtain the necessary data. A conventional display of an ultrasound image, which requires skill and experience to interpret, is eliminated in favor of machine analysis providing an output in abbreviated or cartoon form. 
         [0007]    Specifically, then, the present invention provides, in one embodiment, an ultrasound machine having an ultrasound transducer communicating with an ultrasound processor. The ultrasound transducer has a transducer bar having an upper surface receivable against a palm of a hand placed there against to extend across a lateral axis of the palm and a hand retention element extendable upward from the transducer bar over the back of the hand to retain the transducer bar against the palm. A set of independently excitable transducer elements are displaced laterally within the transducer bar and exposed for ultrasonic transmission and reception at a lower surface of the transducer bar opposite the upper surface. 
         [0008]    The ultrasound processor includes transducer interface circuitry communicating with the independently excitable transducer elements for acquisition of a volume set of ultrasound echo signals, a display and an electronic processor receiving the volume set of ultrasound echo signals. The electronic processor executes a stored program to identify within the volume set of ultrasound echo signals indications of conditions selected from the group of: (i) placenta over cervix; (ii) fetus in non-head down presentation; (iii) multiple gestation; (iv) gestational age; (v) and fetal size; and to output at least one condition on the display. 
         [0009]    It is thus a feature of at least one embodiment of the invention to provide an ultrasound machine that accommodates the practice of existing providers who are untrained in imaging (or even obstetrics) rather than requiring the traditional birth attendants or point-of-care healthcare workers (such as emergency medical technicians) to conform to the requirements of complex ultrasound technology. By offering limited functionality related to obstetrical care, the complexity of ultrasound diagnosis can be largely managed automatically. By adapting the transducer to be compatible with current practices of the attending assistant, training time is substantially reduced and acceptance of the equipment into the practice of those actually available to provide healthcare is greatly increased. 
         [0010]    The hand retention element and transducer bar may be substantially symmetric across the lateral axis to receive either the left or right hand. 
         [0011]    It is thus a feature of at least one embodiment of the invention to provide a transducer that may be employed in a familiar hand position with palm toward the patient when used in either the left or right hand, allowing for complete data acquisition 
         [0012]    The ultrasound producer may include indicia indicating preferred movement direction. 
         [0013]    It is thus a feature of at least one embodiment of the invention to assist in the automatic identification of the orientation of the acquired data through enforcement of a single orientation of the transducer on the hand, left or right. 
         [0014]    The ultrasound machine may output the measured condition independent of a representation of an image of the volume set of ultrasonic echo signals. 
         [0015]    It is thus a feature of at least one embodiment of the invention to eliminate the need for interpreting an image to obtain the needed clinical information. 
         [0016]    In some embodiments, the invention may output the measured condition without outputting a representation of an image of the volume set of ultrasonic echo signals and in a way that is free from information identifying gender. 
         [0017]    It is thus a feature of at least one embodiment of the invention to avoid enabling gender selection. 
         [0018]    The electronic processor may further output on the display indications guiding movement of the ultrasonic transducer to obtain the volume set of ultrasonic echo signals. 
         [0019]    It is thus a feature of at least one embodiment of the invention to provide a system that may be used with little or no training by providing real-time user instructions directly into the display. 
         [0020]    The indications guiding movement of the ultrasonic transducer may be based on concurrent, analysis of the received ultrasound signals by the electronic processor, for example, as to quantity and location and/or based on real-time analysis of fetal structure. In this latter case, the indications guiding movement of the ultrasound transducer may be based on identified fetal structure that must be measured for identification of the at least one condition. 
         [0021]    It is thus a feature of at least one embodiment of the invention to provide guidance in using the ultrasound machine that is responsive to the ongoing data collection process and thus that provides continued guidance to the user. It is a thither feature of this embodiment to inform the guidance provided by the user, on a real-time basis, using the same features that allow for automatic ultrasound analysis, that is, to allow concurrent automatic analysis of the data to adjust the user&#39;s actions toward the goal of improving the intended measurements of the automatic analysis. 
         [0022]    The indications guiding movement of the ultrasound transducer provide a representation of the ultrasonic transducer positioned, on a representation of the mother&#39;s abdomen. 
         [0023]    It is thus a feature of at least one embodiment of the invention to provide a simple, intuitive, and largely language-free guidance to the user. 
         [0024]    These particular objects and advantages may apply to only some embodiments falling within the claims and thus do not define the scope of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]      FIG. 1  is a perspective view of the ultrasound machine of the present invention showing the transducer design as is adapted for better compatibility with traditional obstetrical practice, and further showing a remote display unit communicating with this transducer: 
           [0026]      FIG. 2  is a block diagram of the transducer and display unit of  FIG. 1  showing positioning of the ultrasound transducer elements and showing a first and second electronic computer for processing ultrasound data in the transducer and generating a display in the remote display unit; 
           [0027]      FIG. 3  is a flowchart showing a program executed jointly or individually by the computers of  FIG. 2  in implementing the present invention; 
           [0028]      FIG. 4  is a representation of a first display provided by the display unit of  FIG. 1  guiding movement of the ultrasound transducer by the operator according to real-time measurements and analysis of received ultrasound signals; 
           [0029]      FIG. 5  is a representation of a second display provided by the display unit of  FIG. 1  providing output indication of fetal conditions; 
           [0030]      FIG. 6  is a perspective view of the transducer and data acquired by the transducer within a desired volumetric data set with respect to stitching data together to provide the volumetric data set; and 
           [0031]      FIG. 7  is a flowchart of a segmentation procedure used by the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0032]    Referring now to  FIG. 1 , an ultrasound system  10  of the present invention may include an ultrasound transducer  12  for acquiring ultrasound echo data and communicating that ultrasound data with a display unit  14  for the display of information related to acquired ultrasound data. As shown, the transducer  12  and display unit  14  are separate so as to aid in the viewing of the display unit  14  during scanning of the transducer  12 : however, it is contemplated that these two elements can be integrated into a single device. When separate, the transducer  12  may communicate with the display unit  14 , for example, wirelessly by radio, ultrasound, or optical signals  16  or by means of a flexible electrical conductor. 
         [0033]    Referring now to  FIGS. 1 and 2 , the transducer  12  may include a transducer bar  18  receivable against a palm of the user&#39;s hand  20  to extend generally along a lateral axis  22  with respect to the hand  20  across the width of the hand  20  over the palm. A hand retention bar  24  may be spaced above the transducer bar  18 , generally parallel to the transducer bar  18 , as supported by left and right side pillars  26   a  and  26   b.  In this way, the hand retention bar  24  may fit against the back of the user&#39;s hand  20  when the user&#39;s hand  20  is placed within an opening  28  between the pillars  26   a,    26   b  and between the upper surface of the transducer bar  18  and the lower surface of the hand retention bar  24 . The hand retention bar  24  and the pillars  26   a  and  26   b  allow the transducer  12  to be manipulated with a light grip by the user&#39;s hand  20  in a manner that orients the user&#39;s hand in a traditional orientation for a sweeping of the abdomen  21  of a patient. The pillars  26   a  and  26   b  on the underside of hand retention bar  24  may be lightly padded to help the user retain possession of the transducer  12  during use and to prevent the need for a tight grip on the transducer bar  18  in order to control lateral and vertical motion of the transducer  12 . 
         [0034]    As shown in  FIG. 1 , an upper surface of the hand retention bar  24  may provide a directional indicia  30  indicating a preferred sweep direction of the transducer  12  generally perpendicular to the lateral axis  22 . The transducer  12  is generally symmetrical across a central plane perpendicular to the lateral axis  22  to he equally received by the user&#39;s left or right hand. The indicia  30  helps preserve the consistent orientation of the transducer  12  when the user switches hands. 
         [0035]    An upper surface of the hand retention bar  24  may also include control features such as an indicator light  32  indicating activation and proper functioning of the ultrasound system  10  in communication with the display unit  14 , and an activation button  34  that may control the application of power to internal electronics of the transducer  12  in the manner of a conventional on-off switch. 
         [0036]    Referring still to  FIG. 2 , positioned within the transducer bar  18  are a set of independent transducer elements  36  each capable of emitting ultrasonic acoustic waves into tissue in contact with the underside of the transducer bar  18  and of receiving and detecting echo signals from those emitted ultrasonic acoustic waves for the generation of ultrasonic data. The transducer elements  36  are independently controllable so as to provide separate diverging ultrasonic beams  38  that may be controlled in amplitude and phase for beamforming and other known techniques and are spaced along the lateral axis  22 . 
         [0037]    The transducer elements  36  may communicate with driver circuitry  40  of a type known in the art for providing appropriate voltage signals for driving the transducer elements  36  and for detecting voltage signals representing received echo signals from the transducer elements  36 . 
         [0038]    An internal cavity in the transducer bar  18  holding the transducer elements  36  and the driver circuitry  40  may communicate, for example, through an interconnected cavity in pillar  26   a  with additional circuitry held in a corresponding cavity of the hand retention bar  24 . This latter cavity may include a battery  41  and processing circuitry  42  and communication interface  44 , the latter two elements powered by the battery  41 . As is understood in the art, the processing circuitry  42  may be an electronic computer having nonvolatile memory for holding a stored program as will be described below. The communication interface  44  may be a conductor driver or a wireless transceiver operating to produce the signal  65  discussed above. 
         [0039]    Referring still to  FIG. 2 , communication interface  44  may communicate the corresponding communication interface  46  in the display unit  14 . Like the transducer  12 , the display unit  14  may include a battery  48  providing power to the communication interface  44  as well as power to processing circuitry  50  and display screen  52  for displaying image data  53  and/or text and numeric data  54 . As with processing circuitry  42 , processing circuitry  50  may include an electronic computer holding a stored program held in computer memory for controlling other elements of the display unit  14 , in one embodiment, the display unit  14  may be implemented through the use of a smart phone tablet or the like. 
         [0040]    Referring now to  FIG. 3 , in operation, the user may activate the display unit  14  and transducer  12 , for example, by conventional switches on each, to receive, as indicated by process block  56 , ultrasound acquisition instructions to begin an examination. Processing circuitry  42  within the transducer  12  may automatically detect contact of the transducer  12  with the patient so that the operator is not concerned with control of the ultrasound system  10  after activation and before measurements have been reported. 
         [0041]    Referring now to  FIG. 4 , the instructions for acquiring ultrasound data may be provided to the user during the scanning process. Preferably this is done by depicting on the screen  52  a modeled image  55  of the patient&#39;s abdomen, represented internally in three dimensions, so that a two-dimensional image projection can be displayed in various rotations as shown by rotational arrow  57  to show the left and right side of the abdomen for better indicating a range of desired scanning trajectory. Superimposed on this modeled image  55  is a representation of the hand  20  of the operator placed in the transducer  12 , the latter depicting the indicia  30 . The representation of the hand  20  may be placed at the end of a desired sweeping trajectory  58  or may be animated to move along the desired sweeping trajectory  58 . The modeled image  55  may include a phantom outline of a cartoon fetus  60  to provide additional visual reference although it should be emphasized that the model of the patient&#39;s abdomen and the phantom outline of the fetus  60  are preferably cartoons and not derived from actual ultrasound data. 
         [0042]    Referring to  FIGS. 3 and 6 , as the transducer  12  is moved along various trajectories  58 , it will obtain at each point in the trajectory  58  a fan beam slice  62  of ultrasonic echo data caused by successive excitations of the transducer elements  36  and reception of echo signals as is generally understood in the art. As indicated by process block  64 , these slices may be “stitched” together into partial volumes  66  of a desired volumetric data set  67 , for example, by correlating features at adjacent sides of each slice  62 . At this time a superior/interior axis  68  is determined based on knowledge of the order of acquisition of the slices  62  from the user following the trajectory  58 . Alternatively this superior/inferior axis  68  may be determined from anatomical landmarks extracted from the volume set that will be acquired. 
         [0043]    At the conclusion or during each sweep collecting slices  62  of a partial volume  66 , the instructions of process block  56  may be revised, for example, to show a new trajectory  58 . This depiction of the trajectory  58  may include rotation of the modeled image  55  as appropriate and a changing of the image of the hand of the user as well as rotation of the orientation of the representation of the transducer  12  indicated by arrow  63 . In addition, and as shown in  FIG. 4 , a three-dimensional shading  72  may be placed over the outline of the fetus  60  showing roughly the acquired data of each partial volume  66  to guide the user in obtaining data over the entire volumetric data set  67 . 
         [0044]    As indicated by process block  70 , as additional partial volumes  66  are obtained at process block  69 , those volumes are stitched together at process block  76 . Again this process may make use of a correlation of adjacent partial volumes  66  and/or common anatomical references. In this latter case, for example, the border between the amniotic fluid and uterine wall provides a sharp contrast reference point for the alignment of images. This technique is described in “A three-dimensional, extended field of view ultrasound method for estimating large strain mechanical properties of the cervix during pregnancy” by Michael House, Helen Feltovich Timothy J Hall, Trevor Stack, Atur Patel, and Simona Socrate in Ultrasound Imaging. 2012 January; 34(1): 1-14, hereby incorporated by reference together with the references cited therein. 
         [0045]    As these partial volumes  66  are collected at process block  76 , instructions of process block  56  are again updated to show new trajectories  58  or repetitions of old trajectories  58  and to update the shading  72 . Note that generally the shading  72  may include several intensities, for example, reflecting the desire for oversampling through multiple passes by the transducer  12 . 
         [0046]    As the partial volumes  66  are collected, analysis can begin as indicated by process block  80  in which the acquired data is segmented to identify the anatomical structure of the fetus. The early stages of the segmentation and analysis may further be used to modify the instructions for acquisition of process block  56  as indicated by dotted line  78  which may lead to more acquisition along additional trajectories  58  with different orientations. For example, in measurement of the fetal femur length or the crown-rump length of the fetus, an evolving understanding of the segmentation of volumetric data set  67  and the position of the fetus may be used to promote additional acquisition along different planes that better reveal data for this measurement. 
         [0047]    Referring now also to  FIG. 5 , when the completion of data acquisition of the desired volumetric data set  67  is complete, as indicated by process block  82 , an output may be provided on the screen  52  of the display unit  14  providing an indication of one or more conditions relevant to the developing fetus including (i) placenta over cervix; (ii) fetus in non-head down presentation; (iii) multiple gestation; (iv) gestational age; and (v) fetal size. As is generally understood in the art, the placenta over the cervix (placenta previa) occurs when the placenta partially or totally covers the opening in the cervix which can cause bleeding or infection from obstructed labor. The fetus in the non-head down presentation (fetal malpresentation) refers to any position of the fetus other than a vertex presentation with the top of the head closest to the pelvic inlet of the birth canal such as can present difficulties in labor. Multiple gestation, for example, indicates the presence of twins or the like. Gestational age is the amount of time since conception and fetal size may be measured in a variety of ways including head size, femur size, and crown-to rump-length. 
         [0048]    Desirably, this information is communicated either quantitatively as a number  84 , or is a quantitative graphic, for example, a marker arrow showing the desired value and position within a bar  86  that establishes both a range of possible values and indicates sub-ranges associated with desired values. The meaning of each measurement, for example, measures of fetal size such as head size or femur length, may be diagrammically illustrated on a cartoon  88  of the fetus. Preferably no image derived from the ultrasound data that is collected will be displayed, to prevent attempts to diagnose with the use of the image; however, thumbnail images may be provided in a form that doesn&#39;t allow for gender identification. 
         [0049]    When the output value is described against the range, for example, in a quantitative graphic, the range or sub-ranges may be adjusted according to other measured conditions, for example, gestational age. In this way, for example, the values may be provided in the context of desired values for a given gestational age. With respect to the conditions (i)-(iii), the cartoon  88  may be altered to illustrate those conditions, for example, by adding a cartoon  90  of the placenta for (i), inverting the image of the cartoon  88  within a cartoon perimeter  92  of the uterus for (ii). Or adding a second fetal cartoon  88  in the case of multiple gestations of condition 
         [0050]    Referring now to  FIG. 7 , the process of segmentation and analysis of  FIG. 3  is desirably performed automatically by segmentation and analysis programs that eliminate the need for the user to have acquired skills in reading ultrasound images. Accuracy in this process is enabled by the constrained use of the ultrasound system  10  for detecting specific conditions. The automatic segmentation analysis problem may be treated as an “ordered detection problem” in which more easily identified anatomical structures are identified first and then these structures are used as reference points to locate subsequent harder to identify structures. Thus, the approach provides a multi-resolution approach that computes the likelihood that a structure is in a particular location given the structures already identified and their relative locations. 
         [0051]    As indicated by process block  100 , the superior/inferior axis  68  shown in  FIG. 6  that will be used for the analysis process is first identified either as discussed above or through a general analysis of the volumetric data for anatomical features such as pelvic bone structures and the like. 
         [0052]    At process block  102 , fetal head structure is identified, for example, by correlating against a model of the fetal head at various sizes that captures the bright reflection of the skull bone against the dark shadow of surrounding amniotic fluid, the generally spherical shape of the skull, and the expected ultrasonic characteristics of the brain tissue. Various fetal head sizes may be applied and at this point multiple heads may be identified for the purposes of identifying condition (iii) of multiple gestations. For each identified head, per process block  102 , body structure may be identified per process block  104  as a tissue mass extending from an identified head by an expected distance and volume based on head diameter. The portion of the identified fetal body structure may then be analyzed to find an appropriate length femur structure consistent with the head size and location in the body structure according to empirically established zones within the body structure. 
         [0053]    Measurement of the head size, femur length and crown-rump length may then be performed for condition (v). At this point the relationship between the head and the body structure and the known superior/inferior axis  68  developed at process block  100  will provide for an indication of condition (ii) of the fetal in the non-head down presentation. The known superior/inferior axis  68  together with an identification of the head and body structure of the fetus may be used to determine whether there is a placental structure over the cervix per condition (i). Gestational age may be computed according to the fetal size measurements in light of whether there are multiple gestations completing the measurements of process block  106 . These conditions may then be output as described above with respect to process block  82  of  FIG. 3   
         [0054]    Segmentation techniques for fetal measurement are described generally in U.S. Pat. No. 8,556,814 “Automated fetal measurement from three-dimensional ultrasound data”; U.S. Pat. No. 7,995,820 “System and method for detection of fetal anatomies from ultrasound images using a constrained probabilistic boosting tree”; U.S. Pat. No. 7,783,095 “System and method for fetal biometric measurements from ultrasound data and fusion of same for estimation of fetal gestational age”; and U.S. Pat. No. 7,400,767 “ System and method for graph cuts image segmentation using a shape prior”; all hereby incorporated by reference. 
         [0055]    Certain terminology is used herein for purposes of reference only, and thus is not intended to be limiting. For example, terms such as “upper”, “lower”, “above”, and “below” refer to directions in the drawings to which reference is made. Terms such as “front”, “back”, “rear”, “bottom” and “side”, describe the orientation of portions of the component within a consistent but arbitrary frame of reference which is made clear by reference to the text and the associated drawings describing the component under discussion. Such terminology may include the words specifically mentioned above, derivatives thereoff, and words of similar import. Similarly, the terms “first”, “second” and other such numerical terms referring to structures do not imply a sequence or order unless clearly indicated by the context. 
         [0056]    When introducing elements or features of the present disclosure and the exemplary embodiments, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of such elements or features. The terms “comprising” ;  “including” and “having” are intended to be inclusive and mean that there may be additional elements or features other than those specifically noted. It is further to be understood that the method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed. 
         [0057]    References to “a microprocessor” and “a processor” or “the microprocessor” and “the processor,” can he understood to include one or more microprocessors that can communicate in a stand-alone and/or a distributed environment(s), and can thus be configured to communicate via wired or wireless communications with other processors, where such one or more processor can be configured to operate on one or more processor-controlled devices that can be similar or different devices. Furthermore, references to memory, unless otherwise specified, can include one or more processor-readable and accessible memory elements and/or components that can be internal to the processor-controlled device, external to the processor-controlled device, and can be accessed via a wired or wireless network. 
         [0058]    It is specifically intended that the present invention not be limited to the embodiments and illustrations contained herein and the claims should be understood to include modified forms of those embodiments including portions of the embodiments and combinations of elements of different embodiments as come within the scope of the following claims. All of the publications described herein, including patents and non-patent publications, are hereby incorporated herein by reference in their entireties.