Patent Publication Number: US-2009227869-A1

Title: Volume Measurement In An Ultrasound System

Description:
The present application claims priority from Korean Patent Application No. 10-2008-0020301 filed on Mar. 5, 2008, the entire subject matter of which is incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to ultrasound systems, and more particularly to volume measurement in an ultrasound system. 
     BACKGROUND 
     Recently, an ultrasound system has been extensively used in the medical field due to its non-invasive and non-destructive nature. The ultrasound system operates in various image modes such as a brightness mode, a Doppler mode and the like to acquire ultrasound images for diagnosis. Also, the ultrasound system may operate in a measure mode for measuring volumes of parts of interest (e.g., organs, lesions, etc.) contained in a target object. Volume data, which are usually acquired in the brightness mode, may be used to measure the volumes of parts of interest. 
     If the measure mode is set, then the ultrasound system allows a user to input a selection instruction for selecting a reference plane from the volume data. Further, a slice setting instruction for setting a plurality of slices, which are perpendicular to the reference plane and parallel to each other, is inputted. The ultrasound system then sets a seed point at a center of each of the slices to extract a contour of the part of interest on each of the slices. The ultrasound system measures the volume of part of interest based on the extracted contours of the part of interest. 
     In the conventional ultrasound system, however, only one seed point is set at the center of each slice. As such, an error may occur in extracting the contours of the part of interest on the slices. Thus, the volume of part of interest may be inaccurately calculated. Also, since one seed point is set, a volume for only one part of interest can be measured. That is, when a plurality of parts of interest is contained in the target object, the conventional ultrasound system cannot measure the volumes of parts of interest at the same time. 
     SUMMARY 
     Embodiments for measuring volumes of one or more parts of interest are disclosed herein. In one embodiment, by way of non-limiting example, an ultrasound system comprises a volume data forming unit for forming volume data based on ultrasound echoes reflected from a target object, the target object including at least one part of interest; an interface unit for allowing a user to input a selection instruction for selecting a reference plane from the volume data and a slice setting instruction for setting a plurality of slices perpendicular to the reference plane in the volume data; an image processing unit for detecting a contour of the part of interest on the reference plane and determining intersection points of the detected contour and each of the slices as seed points, the image processing unit being further configured to detect contours of the part of interest on the slices based on the seed points; and a volume measuring unit for measuring a volume of part of interest based on the contour on the reference plane and the contours on the slices. 
     In another embodiment, a method of measuring a volume of at least one part of interest contained in a target object in an ultrasound system, which includes a volume data forming unit, an interface unit, an image processing unit and a volume measuring unit, comprises the following steps: a) at the volume data forming unit, forming volume data based on ultrasound echoes reflected from a target object containing at least one part of interest; b) at the interface unit, receiving a selection instruction for selecting a reference plane from the volume data; c) at the image processing unit, detecting a contour of the part of interest on the reference plane; d) at the interface unit, receiving a slice setting instruction for setting a plurality of slices perpendicular to the reference plane in the volume data; e) at the image processing unit, determining intersection points of the detected contour and each of the slices as seed points and detecting contours of the part of interest on the slices based on the seed points; and f) at the volume measuring, measuring a volume of the part of interest based on the contour on the reference plane and the contours on the slices. 
     The Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used in determining the scope of the claimed subject matter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram showing an illustrative embodiment of an ultrasound system. 
         FIG. 2  is a schematic diagram illustrating volume data. 
         FIG. 3  is a schematic diagram showing an example of displaying an ultrasound image of a target object containing a plurality of parts of interest. 
         FIG. 4  is a block diagram showing an illustrative embodiment of an image processing unit. 
         FIG. 5  is a schematic diagram showing an example of setting a plurality of slices on a reference plane for determining seed points. 
         FIG. 6  is a schematic diagram showing an example of detecting a contour of a part of interest on a slice by using seed points and a center point of the seed points. 
         FIG. 7  is a schematic diagram showing an example wherein one contour encompasses the other contour. 
     
    
    
     DETAILED DESCRIPTION 
     A detailed description may be provided with reference to the accompanying drawings. One of ordinary skill in the art may realize that the following description is illustrative only and is not in any way limiting. Other embodiments of the present invention may readily suggest themselves to such skilled persons having the benefit of this disclosure. 
     Referring to  FIG. 1 , an illustrative embodiment of an ultrasound system  100  for measuring volumes of parts of interest contained in a target object is shown. As depicted, the ultrasound system  100  may include a transmission/reception (Tx/Rx) unit  110 . The Tx/Rx unit  110  may be configured to transmit ultrasound signals to a target object and receive ultrasound echoes reflected from the target object. The Tx/Rx unit  110  may be further configured to convert the ultrasound echoes into electrical signals (hereinafter, referred to as “receive signals”). The Tx/Rx unit  110  may include a probe (not shown) containing a plurality of elements for performing reciprocal conversion of ultrasound signals and electrical signals. The Tx/Rx unit  110  may also include a beamformer (not shown) for performing Tx focusing for the ultrasound signals and Rx focusing for the receive signals. 
     The ultrasound system  100  may further include a volume data forming unit  120  that may receive the receive signals from the Tx/Rx unit  110 . A volume data forming unit  120  may form volume data of the target object containing one or more parts of interest (e.g., organs or lesions) based on the receive signals. 
     The ultrasound system  100  may further include an interface unit  130  for allowing a user to input instructions. The instructions may include a selection instruction for selecting a reference plane from the volume data, a contour setting instruction for setting contours of the parts of interest and a slice setting instruction for setting slices on the reference plane. Also, an interface unit  130  may include a display unit capable of allowing the user to input the instructions while displaying an ultrasound image. In one embodiment, the reference plane, the contours and the slices may be defined as follows: 
     (1) The reference plane may be one of an A plane, B plane and C plane in the volume data forming unit  210 , as illustrated in  FIG. 2 . However, the reference plane may not be limited thereto. An arbitrary oblique plane for the A, B or C plane may be also set as the reference plane. 
     (2) The contours may be used to separate a part of interest desired to measure a volume thereof from the other parts on an image of the reference plane (hereinafter, referred to as “reference plane image”). As illustrated in  FIG. 3 , for example, contours  311 ,  312  and  313  may separate parts of interest  321 ,  322  and  323  from the other part  324  on the reference plane image  310 . 
     (3) The slices may be set to be perpendicular to the reference plane. For example, assuming that the A plane is set as a reference plane, the slices may be planes parallel with the B plane (including the B plane), or planes parallel with the C plane (including the C plane). Also, reference slices  412  and  414  may be set on both ends on the reference plane  310  in response to the slice setting instruction, as illustrated in  FIG. 5 . The number of slices to be set between the reference slices  412  and  414  may be also determined in response to the slice setting instruction. Accuracy for the volume measurement of the parts of interest may depend on the reference slices and the number of slices. The reference slices and the number of slices may be appropriately set according to the experience of the user for accurate volume measurement. 
     The ultrasound system  100  may further include a storage unit  140  that may store the volume data formed in the volume data forming unit  120 . The storage unit  140  may further store instructions to implement a contour setting algorithm for automatically setting contours of parts of interest on the ultrasound image. The contour setting algorithm may be implemented based on previously collected contour information of the parts of interest such as human organs. In one embodiment, the contours of the parts of interest on the reference plane image may be automatically set. 
     The ultrasound system  100  may also include an image processing unit  150 . The image processing unit  150  may be configured to form the reference plane image in response to the selection instruction. The image processing unit  150  may further operate to detect the contours of the parts of interest on the reference plane image in response to the contour setting instruction. The image processing unit  150  may form images of a plurality of slices selected in response to the slice selecting instruction (hereinafter, referred to as “slice images”). The image processing unit  150  may set the parts of interest on each of the slice images and determine seed points of the parts of interest based on the previously collected contour information and the slice information. The seed point determination will be described later in detail. The image processing unit  150  may be further configured to detect the contours of the parts of interest based on the determined seed points. 
     The ultrasound system  100  may further include a volume measuring unit  160 . The volume measuring unit  160  may be configured to measure volumes of the parts of interest based on the contour detected on the reference plane image and the contours detected on the slice image. 
     Referring to  FIG. 4 , an illustrative embodiment of the image processing unit  150  is shown. The image processing unit  150  may include a reference plane setting unit  151 . The reference plane setting unit  151  may set the reference plane from the volume data in response to the selection instruction. The reference plane setting unit  151  may extract data corresponding to the reference plane from the volume data to form the reference plane image. The ultrasound system may also include a display unit  170  and the reference plane image may be displayed on the display unit  170 . 
     The image processing unit  150  may further include a contour setting unit  152 . If the contour setting instruction is inputted through an interface unit  130 , then contour setting unit  52  may set contours  311 ,  312  and  313  of the parts of interest  321 ,  322  and  323  on the reference plane image  210 , as shown in  FIG. 3 . On the other hand, if the contour setting instruction is not inputted for a predetermined time period, then the contour setting unit  152  may set the contours of the parts of interest on the reference plane image  310  based on previously set contour information, which may be previously stored in the storage unit  140 . 
     The image processing unit  150  may further include a slice setting unit  153 . If the slice setting instruction is inputted through the interface unit  130 , then the slice setting unit  153  may set a plurality of slices on the reference plane image  210 . The slice setting instruction may include information upon reference slices and the number of slices to be inserted between first and second reference slices  412  and  414 . In one embodiment, the slice setting unit  153  may set first and second reference slices  412  and  414  on the reference plane image  210  based on the reference slice information, as illustrated in  FIG. 5 . The slice setting unit  153  may further set a plurality of slices  421 ,  422 ,  423  and  424  between the first slice  412  and the second slice  414  based on the slice number information (e.g., the number of slices=4). The slices  421  to  424  may be set at a constant interval between the first slice  412  and the second slice  414 . 
     The image processing unit  150  may also include a seed point determining unit  154 . The seed point determining unit  154  may determine seed points on the slice images based on the contours of the parts of interest set on the reference plane image. In one embodiment, the seed point determining unit  154  may determine two points where the slices and the contour of each of the parts of interest intersect, as illustrated in  FIG. 5 . The seed point determining unit  154  may set the two points  321   a  and  321   b,    322   a  and  322   b,  and  323   a  and  323   b  as seed points for the parts of interest  321 ,  322  and  323 , respectively. 
     The image processing unit  150  may further include a slice image forming unit  155 . The slice image forming unit  155  may extract data corresponding to the slices from the volume data stored in the storage unit  140  based on the slices  412 ,  414  and  421 - 424 , which are set on the reference plane image  210 . The slice image forming unit  155  may form slice images corresponding to the slices based on the extracted data. The slice image may be displayed on the display unit  170 . 
     The image processing unit  150  may also include a contour detecting unit  156 . The contour detecting unit  156  may detect the contours of the parts of interest on the slice images based on the determined seed points. Referring to  FIG. 6 , the contour detecting unit  156  may set a center point  510  positioned at a center of two seed points  321   a  and  321   b  on the slice  412 . The contour detecting unit  156  may detect points corresponding to the contour of a part of interest in radial directions with respect to the center point, i.e., edges  530 . In one embodiment, the edges  530  of the part of interest may be determined between a line  521  and a line  522 , which are defined by two seed points  321   a  and  321   b.  The edge detection may be carried out through a conventional method. As such, detailed descriptions thereof are omitted herein. The contour detecting unit  156  may connect the detected edges to each other so that the contour of the part of interest may be set. The contour detecting unit  156  may set the contours of the parts of interest for the entire slices  412 ,  414  and  421 - 424  through the same process as described above. 
     The image processing unit  150  may further include an additional slice processing unit  157 . The additional slice processing unit  157  may set additional slices between two reference slices  412  and  414 . The additional slice processing unit  157  may detect the contours of the parts of interest from the additional slices by using linear interpolation. In one embodiment, the additional slice processing unit  157  may set an additional slice  431  between the slices  412  and  421 . The additional slice processing unit  157  may detect the contours of the parts of interest on the additional slice  431  by performing linear interpolation upon the contours of the parts of interest on the slice  412  and the contours of the parts of interest on the slice  421 . The additional slice processing unit  157  may further set additional slices  432 - 435  in the same manner as described above and then detect the contours of the parts of interest on the additional slices  432 - 435 . 
     The ultrasound system  100  may also include a volume measuring unit  160 . The volume measuring unit  160  may measure an area of the reference part of interest based on the contour of the reference part of interest. Also, the volume measuring unit  160  may measure areas of the parts of interest based on the contours of the parts of interest. In one embodiment, a conventional method of measuring the area with the contour may be adopted. Thus, detailed descriptions of the area measurement will be omitted herein. The volume measuring unit  160  may measure a volume of each of the parts of interest based on the area of the reference part of interest and the areas of the parts of interest. In such a case, the measured volume value may be displayed through the display unit  170 . The volume value may be represented by numeral texts, a bar graph or the like. 
     In one embodiment, the image processing unit  150  may form 3-dimensional ultrasound images of the parts of interest based on the contour of the reference part of interest on the reference slice image and the contours of the parts of interest on the slice images. When the 3-dimensional ultrasound images corresponding to the parts of interest are displayed on the display unit  170  at the same time, overlapping portions may occur. Thus, the image processing unit  150  may apply weights to the 3-dimensional images such that the 3-dimensional images have different transparencies. 
     Although it is described that the contours include the contours for setting the parts of interest, which are separate from each other, on the reference plane image as illustrated in  FIG. 3 , the contours are certainly not limited thereto. As illustrated in  FIG. 7 , the contours may include a first contour  361  for separating a first part of interest  351  from the other parts and a second contour  362  for setting a second part of interest  352  within the first part of interest  351 . 
     As mentioned above, the seed points may be automatically and accurately set by using the reference plane image and the slice images. This is so that the contours of the parts of interest on the slice images may be accurately detected. The volumes of the specific parts may be accurately measured. Also, a plurality of 3-dimensional images of numerous parts of interest may be provided based on the contours of the parts of interest on the reference plane image and the slice images. 
     Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, numerous variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.