Abstract:
A low profile large aperture matrix based ultrasound transducer fixably attached to the human body by a disposable pad and is used to image the human anatomy. The image tuning and field of view is controlled remotely by inputs to the ultrasound imaging system.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a method and apparatus for providing a continuous imaging by an ultrasound transducer system. In particular the present invention relates to a method and apparatus for ultrasound imaging that controls the tuning and positioning of scan lines generated by an array without the need for a manual transducer manipulation. 
         [0003]    2. The Prior Art 
         [0004]    For transthoracic imaging ultrasound transducers are typically hand held against the chest or abdomen. 
         [0005]    In order to provide a continuous imaging of human anatomy for evaluation or therapy, an ultrasound transducer needs to be positioned and held in with very good acoustic coupling and precisely aligned with the targets of interest. Remote transducers have been described by Chanderatna (5598845) and Clancy (5022410) but in both cases mechanical adjustment of the transducer assembly relative to the human anatomy is required for image acquisition. It would be desirable to develop a methodology and an apparatus that permits remote transducer usage without the need for manual adjustment. 
       SUMMARY OF THE INVENTION 
       [0006]    The invention described here is a low profile large aperture matrix based ultrasound transducer fixably attached to the human body by a disposable pad and is used to image the human anatomy. The image tuning and field of view is controlled remotely by inputs to the ultrasound imaging system. 
         [0007]    The matrix array pad applied transducer described here removes the need for mechanical adjustment by utilizing electronic control of scan lines that are positioned by the user controlling the ultrasound imaging system so that it is no longer necessary to manipulate the imaging transducer. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0008]      FIG. 1  is a block diagram of the present invention showing a matrix array sensor assembly controlled by a phased array ultra sound imaging system and a disposable pad is attached to the transducer housing and acoustically coupled to the array; 
           [0009]      FIG. 2  illustrates the patch of  FIG. 1  being attached to a patient&#39;s body in an area of interest; 
           [0010]      FIG. 3  is an alternative embodiment to  FIG. 2  showing multiple patches attached to multiple areas of interest; 
           [0011]      FIGS. 4A and 4B  show an alternative patch—a reusable matrix array patch in which the patch is a reusable patch shown in top and side views, respectively; 
           [0012]      FIGS. 5A and 5B  are top and side views, respectively of the disposable patch of  FIG. 1 ; 
           [0013]      FIGS. 6A and 6B  illustrate a matrix array patch applied to a patient&#39;s body for imaging where imaging is cannot be visualized due to a rib&#39;s shadowing; 
           [0014]      FIGS. 7A and 7B  illustrate how the present invention over comes the problems of imaging in  FIGS. 6A and 6B  due to rib shadowing; and 
           [0015]      FIG. 8  illustrates the phased array ultra sound imaging system control panel of the present invention and the controls for adjusting the imaging by the transducer patch including removing rib shadowing as described in  FIGS. 6A ,  6 B,  7 A and  7 B. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0016]    Referring now to the drawings of  FIGS. 1-8 , a low profile large aperture matrix array sensor assembly controlled by a phased array ultrasound imaging system is shown in  FIG. 1 . The array is held captive in a low profile rigid housing and connected to the imaging system by conventional transducer wiring (although a wireless connection could be any commercially known wireless technology such as but not limited to Bluetooth® technology). A matrix patch lo can be formed as a disposable pad and made of suitable low acoustic loss material such as silicon or equivalent is attached to the transducer housing and acoustically coupled to the array with ultrasound gel. The disposable pad, described in more detail in  FIGS. 5A and 5B , is then attached to the human body in the area of interest with adhesive on its perimeter and acoustically couple to the body with ultrasonic gel. 
         [0017]    Images obtainable from the matrix array include both standard 2D phased or linear array formats as well as 3D real-time volume imaging as described in U.S. Pat. No. 6,679,849. The images may be tuned and manipulated electronically from the ultrasound imaging system. Keyhole imaging may be used for example to image in between ribs if the array pad was inadvertently placed over one during cardiac imaging. Multiple transducers may be envisioned running on the same system depending upon the clinical imaging requirements at hand. 
         [0018]    The low profile matrix array may be of a Capacitive Micromachined Ultrasound Transducer (CMUT)—see U.S. Pat. No. 6,585,653, a Piezoelectric Micromachined Ultrasound Transducer (PMUT)—see U.S. Pat. No. 6,659,954, micro machined ultrasound transducer construction, or of a piezo based construction as described in U.S. Pat. No. 6,679,849. The CMUT would be manufactured using standard integrated circuit processes where capacitively coupled micro machined drums would create the acoustic beams. The ASIC is integrally fabricated as part of the CMUT. The PMUT would be manufactured using integrated circuit processes where piezoelectric elements would create the acoustic beams. The ASIC is fabricated first then the piezo material would be doped afterwards. 
         [0019]    The matrix array assembly would be attached to a rigid transducer housing and preferably a low profile rigid housing, using standard techniques. The acoustic interface materials are known in the art. A low loss pad whose thickness is sufficient to absorb minor changes in human body contours would be manufactured as a disposable such that it could be attached to and later removed from the transducer housing and applied with acoustic gel to insure very good acoustic coupling between transducer and pad. A release film would be applied at the perimeter of the human to pad adhesive interface. Once the transducer position of interest was determined acoustic gel would be applied to the pad and the release film removed and the transducer applied to the patient imaging area. Once good acoustic contact was obtained all imaging control would be input at the imaging system without the need to manipulate the transducer array. 
         [0020]    The imaging system  5  can be phased array ultrasound imaging system  5  for controlling the array  10  so that images from the array  10  include both standard 2D phased and linear array formats as well as 3D real-time imaging as described in U.S. Pat. No. 6,679,849. The ultra sound imaging system  5  could be any suitable commercially known ultrasound imaging system such as but not limited to Philip&#39;s Sonos 7500. The images may be tuned and manipulated electronically from the ultrasound imaging system  5 . This system includes a monitor  6  and a console control  7 . The ultra sound imaging system  5  is connected by wire  8  as shown in  FIG. 1  or wirelessly to the ultra sound transducer  10 . 
         [0021]    The matrix ultrasound transducer can be formed as a patch that adheres to a portion of patient&#39;s for imaging such as cardiac imaging as shown in  FIG. 2 . The wire  8  transmits the images to the ultra sound imaging system  5  for viewing on the monitor  6 . 
         [0022]      FIG. 3  is an alternative embodiment in which several matrix ultra sound transducer patches are affixed to a patient. Such multiple array patches might prove useful for cardiac monitoring by locating the patches over standard cardiac imaging windows on the patient&#39;s body such as the suprasternal, parasternal, and subcostal areas. It is understood that this embodiment is not limited to cardiac imaging but may be used whenever placement of multiple patches may prove useful perhaps when monitoring a pregnant woman and her fetus. 
         [0023]      FIGS. 4  A and  4  B illustrate a reusable patch for the matrix array  10  which matrix array is described in U.S. Pat. No. 6,685,647 using a de-matching layer for low profile assembly. The reusable matrix array is formed of a standard piezoelectric based acoustic stack connected through a ball grid or equivalent interconnect to an ASIC. 
         [0024]      FIG. 4A  shows the top view of the reusable patch  10 .  FIG. 4B  shows the sectional view illustrating the construction of the matrix array reusable patch  10 . As seen in  FIG. 4B  there is an acoustic window  21 ; acoustic matching layers  30 ; a piezoelectric element  31 ; a removable double-sided grade tape  32 ; a plastic housing  22 ; a microbeamforming silican ASIC  25 ; an acoustic de-matching layer  26 ; a stud bump or ball grid array in conductive epoxy used to connect array acoustic elements to microbeamforming ASIC  27  and therefore provides conductivity between the two; an epoxy backfill  33  that isolates the individual conductive elements from each other; a heat sink bonded to ASIC and flexible circuit  23 ; a wire band ASIC to flexible circuit interconnect  24 ; flexible circuits  28 ; and a coax cable array  29 . 
         [0025]      FIGS. 5  A and  5  B illustrate a disposable patch for the matrix array  10  which matrix array is described in U.S. Pat. No. 6,685,647 using a de-matching layer for low profile assembly.  FIG. 5A  shows the top view of the disposable patch  10 .  FIG. 5B  shows the sectional view illustrating the construction of the matrix array disposable patch  10 . As seen in  FIG. 5B  there is an acoustic window  21   a ; a microbeamforming ASIC with active CMUT or PMUT acoustic matrix array integrally attached  30   a ; a permanent double sided medical grade tape affixed in a plastic housing  32   a , a plastic housing  22   a ; a heat sink bonded to ASIC and flexible circuit  23   a ; a wire band ASIC to flexible circuit interconnect  24   a ; flexible circuits  28   a ; an acoustic de-matching layer  35 ; microbeamforming silicon ASIC  36 ; and micro flat ribbon cable assembly  29   a . The patch can be made of silicon or equivalent material with adhesive around its perimeter and acoustically coupled to a patient&#39;s body in the area of interest with ultrasonic gel. 
         [0026]      FIGS. 6A and 6B  illustrate the problem with ultra sound imaging and 3D ultrasound imaging in an imaging mode with a matrix patch that is positioned over an imaging target. The present invention provides for imaging and this includes 2D or 3D imaging. The present invention provides for a novel solution such problems by first providing a system and method for imaging over one or more imaging targets having an obstruction without the need for any mechanical adjustment of the matrix patch but by remote operation of the controls on the ultrasound imaging system  5 . In the example presented rib shadowing is caused by one or more ribs but it is understood that the invention is not limited to this one obstruction or reason for imaging as described herein. Second, the present invention provides for positioning the matrix patch  10  over one or more targets to visualize at least one or more targets by repositioning the sector scans using the controls on the ultrasound imaging system  5 . This makes it possible to visualize multiple targets remotely with the ultrasound imaging system  5 . 
         [0027]    Under these conditions the imaging target underneath the ribs cannot be visualized because of the rib shadowing acoustic scan lines  52   a . As seen in  FIG. 6A  the matrix array patch  10  is adhered to a patient&#39;s body with acoustic gel applied between the transducer and the patient. A 2D scan  51  is produced using a partial aperture available in the matrix array patch  10 . However a patient&#39;s ribs  52  blocks access to acoustic scan lines. 
         [0028]      FIGS. 6A and 6B  illustrate the problem with ultra sound imaging and also with 3D ultrasound imaging in a 2D imaging mode with a matrix patch that is positioned over an imaging target underneath the ribs. This illustration is only one example of an application of the present invention and is not intended to be limited thereto. The present invention, as noted previously, is utilized for sector scanning, volume scanning, and elimination of obstructions while imaging and imaging remotely in more than one area of interest of a patient&#39;s body. Turning now to the specific example where rib shadowing provides an obstruction, under these conditions the imaging target underneath the ribs cannot be visualized because of the rib shadowing acoustic scan lines  52   a . As seen in  FIG. 6A  the matrix array patch  10  is adhered to a patient&#39;s body with acoustic gel applied between the transducer and the patient. A 2D scan  51  is produced using a partial aperture available in the matrix array patch  10 . However a patient&#39;s ribs  52  blocks access to acoustic scan lines. 
         [0029]    The present invention provides a solution to this problem as shown in  FIGS. 7A ,  7 B and  FIG. 8 . 
         [0030]    In  FIGS. 7A and 7B  the matrix array patch  10  is applied with the acoustic gel to the patient&#39;s body with the acoustic gel being applied between the transducer and the patient. Again the patient&#39;s ribs  52  block access to acoustic scan lines. The 2D sector scan  51   a  is repositioned from the imaging system&#39;s  5  console  7  by utilizing the console controls touch screen keys  54  and the trackball  55 . 
         [0031]    The trackball  55  is rotated accordingly to scroll the image to the left or to the right in order to position the image with the rib out of the way. The soft key controls  54  also provide various movement of the image as indicated in  FIG. 8  such as tilt, elevation, biplane rotate, etc. for movement of the image from the rib seen in  FIG. 7B . The 3D ultrasound system operates in a 2D imaging mode with a matrix patch  10  that is positioned over an imaging target and can visualize the image by repositioning sector scanning horizontally using a remote system control  5 . 
         [0032]    As stated previously the controls on these consoles can be used to image targets having any obstructions or for visualizing more than one target and the present invention is not limited to any one particular use. 
         [0033]    The present invention provides for ultrasound imaging without the need for repositioning the matrix array patch and also for removing obstructions such as rib shadowing remotely. 
         [0034]    While presently preferred embodiments have been described for purposes of the disclosure, numerous changes in the arrangement of method steps and apparatus parts can be made by those skilled in the art. Such changes are encompassed within the spirit of the invention as defined by the appended claims.