Abstract:
A diagnostic ultrasound system is provided for automatically displaying multiple planes from a volume of interest. The system comprises a transducer for acquiring ultrasound data associated with a volume of interest having a target object therein. They system further comprises a user interface for designating a reference plane within the volume on interest. A processor module receives patient specific information representative of at least one of a shape and size of the target object and maps the reference plane and the ultrasound data into a 3D reference coordinate system. The processor module automatically calculates at least one plane of interest within the 3D reference coordinate system based on the reference plane and the patient specific information.

Description:
RELATED APPLICATION  
       [0001]     The present application relates to and claims priority from Provisional Application Ser. No. 60/793,908 filed Apr. 20, 2006 titled “SYSTEM AND METHOD FOR AUTOMATICALLY OBTAINING ULTRSOUND IMAGE PLANES BASED ON PATIENT SPECIFIC INFORMATION”, the complete subject matter of which is hereby expressly incorporated in its entirety. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     Embodiments of the present invention relate generally to systems and methods for automatically obtaining ultrasound image planes of the volume of interest, and more specifically for automatic image plane calculation based upon patient specific information.  
         [0003]     Ultrasound systems are used in a variety of applications and a by a variety of individuals with varied levels of skill. In many examinations, operators of the ultrasound system review selected combinations of ultrasound images in accordance with predetermined protocols. In order to obtain the desired combination of ultrasound images, the operator steps through a sequence of operations to identify and capture one or more desired image planes. At least one ultrasound system has been proposed, generally referred to in as automated multiplanar imaging that seeks to standardize acquisition and display of the desired image planes. In accordance with this recently proposed ultrasound system, a volumetric image is acquired in a standardized manner and a reference plane is identified. Based upon the reference plane, multiple image planes are automatically obtained from an acquired volume of ultrasound information without detailed intervention by the user to select each of the multiple image planes.  
         [0004]     However, conventional ultrasound systems have experience certain limitations. The conventional automated multiplanar imaging process progresses independent of, and without consideration for, characteristics of the target object that render the target object unique and size and shape. Consequently, when a reference plane is identified, the multiple images that are automatically calculated may not be properly positioned within or relative to the target object if the size and shape of the target object differ from the standard.  
         [0005]     A need remains for an improved method and system that affords automated multiplanar imaging, while remaining adaptable to different types, shapes and sizes of objects.  
       BRIEF DESCRIPTION OF THE INVENTION  
       [0006]     In accordance with an embodiment of the present invention, a diagnostic ultrasound system is provided for automatically displaying multiple planes from a volume of interest. The system comprises a transducer for acquiring ultrasound data associated with a volume of interest having a target object therein. They system further comprises a user interface for designating a reference plane within the volume on interest. A processor module receives patient specific information representative of at least one of a shape and size of the target object and maps the reference plane and the ultrasound data into a 3D reference coordinate system. The processor module automatically calculates at least one plane of interest within the 3D reference coordinate system based on the reference plane and the patient specific information.  
         [0007]     For example, the volume of interest may constitute an organ of a fetus (e.g. the myocardium, the head, a limb, the liver, an organ and the like). The patient specific information may include geometric parameters (e.g. diameter, circumference, an organ type identifier in the like). Alternatively, or in addition, the patient specific information may include non-geometric parameters (e.g. age, weight, sex and the like). Optionally, the processor module may calculate a translation distance and a rotation distance from the reference plane to determine a position and orientation of the plane of interest within the 3D reference coordinate system, wherein the translation and rotation distances are based on an age of a patient. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]      FIG. 1  illustrates a block diagram of a diagnostic ultrasound system formed in accordance with an embodiment of the present invention.  
         [0009]      FIG. 2  illustrates a table storing an association between patient specific information and automatic image planes to be generated in accordance with an embodiment of the present invention.  
         [0010]      FIG. 3  represents a graphical representation of image planes that may be automatically calculated from a reference plane in accordance with an embodiment of the present invention.  
         [0011]      FIG. 4  represents and other graphical representation of image planes that may be automatically calculated from a reference plane in accordance with an embodiment of the present invention.  
         [0012]      FIG. 5  illustrates a processing sequence to obtain ultrasound image planes from a pre-acquired 3-D data set in accordance with an embodiment of the present invention.  
         [0013]      FIG. 6  illustrates a processing sequence to obtain selected 2-D ultrasound image planes in accordance with an embodiment of the present invention.  
         [0014]      FIG. 7  illustrates a processing sequence to obtain ultrasound image planes based upon measured anatomic structures in accordance with an embodiment of the present invention.  
         [0015]      FIG. 8  illustrates a processing sequence to obtain ultrasound image planes a real-time continuously updated 3-D data set in accordance with an embodiment of the present invention.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0016]      FIG. 1  illustrates a block diagram of an ultrasound system  100  formed in accordance with an embodiment of the present invention. The ultrasound system  100  includes a transmitter  102  which drives an array of elements  104  within a transducer  106  to emit pulsed ultrasonic signals into a body. A variety of geometries may be used. The ultrasonic signals are back-scattered from structures in the body, like blood cells or muscular tissue, to produce echoes which return to the elements  104 . The echoes are received by a receiver  108 . The received echoes are passed through a beamformer  110 , which performs beamforming and outputs an RF signal. The RF signal then passes through an RF processor  112 . Alternatively, the RF processor  112  may include a complex demodulator (not shown) that demodulates the RF signal to form IQ data pairs representative of the echo signals. The RF or IQ signal data may then be routed directly to RF/IQ buffer  114  for temporary storage.  
         [0017]     The ultrasound system  100  also includes a signal processor  116  to process the acquired ultrasound information (i.e., RF signal data or IQ data pairs) and prepare frames of ultrasound information for display on display system  118 . The signal processor  116  is adapted to perform one or more processing operations according to a plurality of selectable ultrasound modalities on the acquired ultrasound information. Acquired ultrasound information may be processed in real-time during a scanning session as the echo signals are received. Additionally or alternatively, the ultrasound information may be stored temporarily in RF/IQ buffer  114  during a scanning session and processed in less than real-time in a live or off-line operation. An image buffer  122  is included for storing processed frames of acquired ultrasound information that are not scheduled to be displayed immediately. The image buffer  122  may comprise any known data storage medium.  
         [0018]     The signal processor  116  is connected to a user interface  124  that controls operation of the signal processor  116  as explained below in more detail. The display system  118  includes one or more monitors that present patient information, including diagnostic ultrasound images to the user for diagnosis and analysis.  
         [0019]     The system  100  obtains volumetric data sets by various techniques (e.g., 3D scanning, real-time 3D imaging, volume scanning, 2D scanning with transducers having positioning sensors, freehand scanning using a Voxel correlation technique, 2D or matrix array transducers and the like). The transducer  106  is moved, such as along a linear or arcuate path, while scanning a region of interest (ROI). At each linear or arcuate position, the transducer  106  obtains scan planes that are stored in the memory  114 .  
         [0020]      FIG. 2  illustrates a table  200  that stores the relation between patient specific information  202  and predetermined automatic image planes of interest  204 . Each plane of interest  204  is associated in the table  200  with a series of translation and rotation coordinates  206  and  208 , respectively. In the example of  FIG. 2 , the three-dimensional reference coordinate system is in Cartesian coordinates (e.g. XYZ). Thus, the translation coordinates  206  represent translation distances along the X, Y and Z axes. The rotation coordinates  208  represent rotation distances about the X, Y and Z axes. The translation and rotation coordinates  206 ,  208  extend from a reference plane.  
         [0021]      FIG. 3  represents a graphical representation of image planes that may be automatically calculated from a reference plane in accordance with an embodiment of the present invention.  FIG. 3  illustrates a three-dimensional reference coordinate system  300 , in which a reference plane  302  has been designated. The reference plane  302  may be acquired as a single two-dimensional image (e.g. B-mode image or otherwise). Alternatively, the reference plane  302  may be acquired as part of a three-dimensional scan of a volume of interest. For example, the reference plane may constitute a four chamber view of a fetal heart, the right ventricular outflow, the left ventricular outflow, the ductal arch, the aortic arch, venous connections, and the three vessel view. Once the reference plane  302  is adjusted and reoriented until the reference plane  302  contains a reference anatomy  324 . Once the reference plane  302  is acquired, it is mapped into the 3-D reference coordinate system  300 . In the example of  FIG. 3 , the reference plane  302  is located distances  313 - 316  from the origin  311  of the 3-D reference coordinate system  300  along the X, Y, and Z axes.  
         [0022]     After acquiring the reference plane  302  and the fetal age, the processor module  116  automatically calculates additional image planes of interest based upon patient specific information, such as the age of a fetus. The patient specific information may constitute a geometric parameter, and nongeometric parameter or a combination thereof. The patient specific information may provide one-dimensional, two-dimensional or three-dimensional information regarding the target organ. Examples of geometric parameters are an identification of a type of organ, a diameter, a circumference, a length, an organ dimension and the like. The type of organ may be the heart, head, liver, arm, leg or other organ. Examples of non-geometric parameters are age, weight, sex and the like. For example, when examining a fetus that is in week 15 of gestation, a fetal organ or area of interest may be positioned, relative to the reference anatomy  324 , at a position denoted by image  325 . Once the processor module  116  receives the fetal age, processor module accesses the table  200  to obtain the translation coordinates X 1 , Y 1 , and Z 1  and the rotation coordinates A 1 , B 1 , and C 1 . The position and orientation of the image plane  304  is determined from the translation and rotation coordinates.  
         [0023]     Alternatively, when the fetus is in week 17, a fetal organ or area of interest may be positioned, relative to the reference anatomy  324 , at a position denoted by images  326  and  327 . After acquiring the reference plane  302  and the fetal age, the processor module  116  automatically calculates the positions and orientations of image planes  305  and  306 . The image planes  305 - 306  of interest are located within the 3-D reference coordinate system  300 , but are translated and rotated from the position of the reference plane  302  by predetermined distances.  
         [0024]     Thus, the positions of each image plane  304 - 306  is defined relative to the reference plane  302  based upon the fetal age. For example, image plane  306  is translated in the Z direction by a distance  310  from the reference plane  302 , while the image plane  304  is rotated about the Z axis by a predetermined arc in degrees  312 . The image plane  305  is both translated and rotated about multiple axes from the reference plane  302 .  
         [0025]      FIG. 4  represents another graphical representation of image planes that may be automatically calculated from a reference plane in accordance with an embodiment of the present invention. In  FIG. 4 , a three-dimensional reference coordinate system  400  is illustrated in Cartesian coordinates. Optionally, the coordinate reference system may be defined in polar accordance. Optionally, the reference plane  402  may be mapped to the origin  411  of the reference coordinate system  400 . In the example of  FIG. 4 , image planes  404  and  405  are automatically calculated based upon the reference plane  402  when the fetus is 20 weeks old, while image planes  406 - 407  are automatically calculated based upon the reference plane  402  when the fetus is 22 weeks old. The image planes  406 - 407  are spaced further from the reference plane  402 , along the Z direction, to account for the increased length of the organ of interest.  
         [0026]      FIG. 5  illustrates a processing sequence to obtain ultrasound image planes from a pre-acquired 3-D data set in accordance with an embodiment of the present invention. Beginning at  502 , a 3-D data set of ultrasound data is acquired for a volume of interest. At  504 , the user selects a reference plane from the volume of interest. Once the user selects the reference plane, the reference plane may be mapped into a three-dimensional reference coordinate system. At  506 , patient specific information is entered that represents the shape and/or size of the organ of interest within the volume of interest. For example, the patient specific information may be manually entered by the user (e.g. entering the age of a fetus). Alternatively, the patient specific information may be automatically calculated from other anatomic characteristics or structures within the reference plane. As a further option, the patient specific information may be obtained by accessing medical records previously saved and updated for the patient under examination. For example, the age of a fetus may be automatically calculated based upon the social security number or other unique ID of the patient by accessing the patient&#39;s medical records previously entered and updated in accordance with a pregnancy.  
         [0027]     At  508 , one or more image planes of interest are calculated within the three-dimensional reference coordinate system. At  510 , ultrasound images, associated with the automatically calculated image planes, are obtained from the 3-D data set and presented as ultrasound images to a user in a desired format.  
         [0028]      FIG. 6  illustrates a processing sequence to obtain select 2-D ultrasound image planes in accordance with an embodiment of the present invention. At  602 , patient specific information is entered that represents the shape or size of the organ of interest within the volume of interest. At  604 , a two-dimensional ultrasound slice or scan is acquired from within a volume of interest. At  604 , the system need not yet perform a complete three-dimensional volumetric scan. Instead, at  604 , a single slice or planar scan may be acquired. At  606 , the user is afforded the ability to adjust the orientation and position of the probe in order to acquire a desired reference plane through a volume of interest. At  608 , one or more image planes are calculated within a 3-D reference coordinate system based upon the select reference plane and the patient specific information. At  610 , one or more select two-dimensional image planes are acquired from within the volume of interest. The acquired select 2-D image planes correspond to the image planes of interest calculated at  608 . Optionally, the entire volume of interest need not be scanned, but instead the system need only acquire ultrasound information for the select 2-D image planes of interest. At  612 , ultrasound images are displayed for the image planes of interest.  
         [0029]     Optionally, any embodiment of  FIG. 6 , the ultrasound images associated with the select image planes may be continuously updated in real-time at a frame rate sufficiently high, relative to a fetal heart rate, to provide meaningful motion information.  
         [0030]      FIG. 7  illustrates a processing sequence to obtain ultrasound image planes based upon measured anatomic structures in accordance with an embodiment of the present invention. Beginning at seven are two, the system acquires one of a 3-D data set for the volume of interest or one or more two-dimensional slices through the volume of interest. At  704 , the user adjusts the scan orientation to obtain a select reference plane through the volume of interest. At  706 , a measurement is obtained for an anatomic structure within one or both of the reference planes and the volume of interest. For example, the anatomic structure may represent a select bone within a fetus. By measuring the length of the select bone, the fetal age may be automatically determined.  
         [0031]     At  708 , the patient specific information is estimated representative of the shape or size of the volume. At  710 , the image planes of interest are calculated from the 3-D reference coordinate system and at  712  a 3-D data set is acquired (unless already completed). At  714 , one or more ultrasound images are displayed corresponding to the image planes of interest.  
         [0032]      FIG. 8  illustrates a processing sequence to obtain ultrasound image planes in a real-time continuously updated 3-D data set in accordance with an embodiment of the present invention. At  802 , patient specific information is estimated or entered. The patient specific information is representative of the shape or size of the volume. At  804 , image planes of interest are calculated in the 3-D reference coordinate system. In the example of  FIG. 8 , a reference plane has not yet been calculated at  804 . Instead, at  804 , the image planes are calculated relative to the origin of a predetermined 3-D reference coordinate system. The image planes are projected into the predetermined 3D reference coordinate system based upon the assumption that the reference coordinate system and the subsequently acquired volumetric data set will be mapped in a known manner within, and relative to the origin, of the 3-D reference coordinate system.  
         [0033]     At  806 , the probe is positioned to obtain a select reference plane through the volume of interest. At  808 , a 3-D data set of volumetric ultrasound data is acquired. The volumetric data set is mapped into the 3-D reference coordinate system such that the reference plane is positioned at a known location and orientation relative to the origin of the 3-D reference court system. At  810 , ultrasound images are obtained for the image planes calculated at  804 . At  812 , the ultrasound images are displayed.  
         [0034]     It is understood that the above methods and systems may be utilized in connection with a variety of patient types, diagnoses, organs and the like. For example, the organ may be the heart, head, liver, arm, leg and the like.  
         [0035]     While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.