Patent Publication Number: US-2009220135-A1

Title: System, server, method and program for image transfer

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a system comprising a server storing a plurality of groups of digital images and a terminal that is connected communicably to the server and displays an image transferred from the server. The present invention also relates to the server, a method, and a program for the system. 
     2. Description of the Related Art 
     At the time of examination and image processing of a first group of images comprising medical tomographic images or the like such as CT images or MRI images, a second group of images such as MRI images corresponding to the first group of images are generally displayed in parallel for reference. 
     Images belonging to the same group generally have common characteristics. Therefore, after an examiner has completed examination or processing of an image in a first image group, the examiner repeats examination and processing of another image in the first group by display thereof, to complete examination or processing of all images in the group. During display and comparison of an image of a first group and an image of a second group, if another image in the first group is displayed, display of a corresponding image in the second group is desired. 
     For such a case, a method has been proposed in Japanese Patent No. 3639030 wherein an image in a second group corresponding to an image in a first group is automatically determined and displayed in response to display of the image in the first group. 
     However, in the case where the method described in Japanese Patent No. 3639030 is adopted in a general digital image transfer and display system that stores image groups in a server and transfers the image groups to a terminal for display, the image groups to be displayed for comparison are supposed to have been stored in the terminal before examination thereof. 
     For this reason, in order to take advantage of the invention described in Japanese Patent No. 3639030, image groups that are necessary for display and comparison need to be all specified in advance, and no examination or processing of the image groups can unfortunately be started before all images in the image groups are transferred to a terminal. In addition, in the case of medical image interpretation, physicians wish to display and compare relevant images in a second group on a terminal only if necessary after examining a first image group alone. Therefore, if all images in a second group are transferred from the very beginning as has been described above, examiners and systems are burdened with unnecessary transfer time and load. Moreover, in the case where a second image group becomes necessary during interpretation of a first image group alone, images in the second group are always transferred sequentially from the first image therein. Consequently, it is time-consuming for an image in the second group corresponding to an image in the first group being displayed on a terminal to be transferred to the terminal. Before completion of the transfer, the image cannot be displayed and compared, which is troublesome. 
     SUMMARY OF THE INVENTION 
     The present invention has been conceived based on consideration of the above circumstances. An object of the present invention is therefore to provide an image transfer system, a transfer method, and a server and a program therefore that enable efficient transfer and display of a second image group to be displayed on a terminal for comparison with an image in a first image group being displayed on the terminal, in consideration of transfer waiting time for a viewer and a transfer load on the system. 
     An image transfer system of the present invention is an image transfer system comprising a server that stores groups of digital images and a terminal that is connected communicably to the server and displays an image transferred from the server. The system is characterized in that the server stores the groups of images, determines a second one of the image groups corresponding to a first one of the image groups including an image being displayed on the terminal, determines at least one image belonging to the second group and corresponding to the currently displayed image of the first group, determines in what order images in the second group are transferred based on the at least one image having been determined, and transfers the images to the terminal in the order having been determined. 
     The second image group corresponding to the first image group refers to an image group to be displayed for comparison, for diagnosis regarding the first image group. For example, the second image group refers to an image group of the same patient, or an image group of the same patient and the same modality. 
     The at least one image belonging to the second group and corresponding to the image being displayed on the terminal refers to an image to be displayed on the terminal for comparison with the image in the first group being displayed on the terminal. For example, the at least one image refers to an image or images belonging to the second group and representing the same anatomical position as the currently displayed image of the first group, or to an image or images belonging to the second group and having been radiographed or photographed in the same direction as the currently displayed image in the first group. 
     According to the image transfer system of the present invention, in the case where the second image group stored in the server is transferred to and displayed on the terminal for comparison and reference during display of the image in the first group on the terminal, the images in the second group are transferred serially starting from the image or images corresponding to the image in the first group currently displayed on the terminal. Therefore, the waiting time for display of the image or images for comparison can be shortened. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic block diagram showing the configuration of a data transfer system of a first embodiment of the present invention; 
         FIG. 2  shows slice images obtained by CT in the first embodiment; 
         FIG. 3  is a flow chart showing the processing carried out in the data transfer system of the first embodiment; 
         FIG. 4  shows an example of a table storing which images in a series D 1  are related to which images in a series D 0  in the first embodiment; 
         FIG. 5  is a schematic block diagram showing the configuration of a data transfer system of a second embodiment of the present invention; and 
         FIG. 6  is a flow chart showing the processing carried out in the data transfer system in the second embodiment. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, embodiments of the present invention will be described in detail, with reference to the accompanying drawings. 
       FIG. 1  is a schematic block diagram showing the configuration of a data transfer system of a first embodiment of the present invention. As show in  FIG. 1 , the data transfer system in the first embodiment is a medical network system used in the field of medicine, and comprises input modalities  1 , an image server  3 , and an image display terminal  5 . The input modalities  1  are CT and MRI apparatuses that record image data sets. The image server  3  is connected to the input modalities  1  via a network  2 , and stores groups of images recorded by the input modalities  1 . The image display terminal  5  is connected to the image server  3  via a network  4 . 
     In this embodiment, the image groups are groups of tomographic images obtained by CT, and each of the groups is referred to as a series. A series D 0  and a series D 1  have been obtained by radiographing the same patient at different times, and the series D 0  is older than the series D 1 . As shown in  FIG. 2 , the series D 0  and D 1  respectively comprise slice images Im 0 _ 0 , Im 0 _ 1 , Im 0 _ 2 , and so on and Im 1 _ 0 , Im 1 _ 1 , Im 1 _ 2 , and so on. The images in each of the image groups are tomographic images radiographed in this order from the side of the head toward the side of the lower limbs. 
     The general flow of image comparison interpretation will be described first. In the environment described above, a physician transfers all the images in the series D 1  to be interpreted, from the image server  3  to the image display terminal  5 . Thereafter, the physician sequentially displays the slice images in the series D 1  one by one to search for a shadow that may represent abnormality. In the case where the shadow has been found in one of the images, the physician judges whether the shadow is harmful or benign, based on the image alone. If the judgment is difficult by using the image alone, the physician transfers the series D 0  to the terminal  5  in the case where the series D 0  of the same patient obtained for the same body part by the same modality are available. The physician then displays the slice image belonging to the series D 0  and representing the same anatomical position as the image showing the shadow in the series D 1 , together with the image showing the shadow. The physician judges whether a similar shadow is shown in the image in the series D 0 . In the case where the similar shadow has been found, the physician judges whether the shadow is malignant or benign, based on how the shadow has changed in size thereof, for example. 
     The operation of the first embodiment in the situation described above will be described below.  FIG. 3  is a flow chart showing the processing carried out in the data transfer system of the first embodiment. Assume that the series D 0  of the CT images recorded by one of the input modalities  1  has been stored in the image server  3 . 
     At Step S 1 , the series D 1  of the CT images radiographed by one of the input modalities  1  is transferred to the server  3 . 
     At Step S 2 , the series to correspond to the series D 1  is determined. A radiographer of the series D 1  searches the server  3  for the series corresponding to the series D 1 , and specifies the series D 0  of the same patient radiographed by the same input modality. 
     After the corresponding group (that is, the series) D 0  has been determined at Step S 2 , the images are related to each other between the series D 0  and the series D 1  at Step S 3 . At this time, a similarity is found between each of the images Im 1 _ 0 , Im 1 _ 1 , Im 1 _ 2 , and so on of the series D 1  and each of the images Im 0 _ 0 , Im 0 _ 1 , Im 0 _ 2 , and so on in the series D 0 , and each combination of the images between which the similarity is highest is judged to be the images representing substantially the same anatomical position. The combinations are stored in the form of a table as shown in  FIG. 4 . To find the similarity, a sum of differences or a correlation coefficient may be used. Although the corresponding images are simply determined based on the combinations of the images of highest similarity, a correction may be applied in consideration of continuous slicing positions. 
     The steps described above have been completed before a physician carries out interpretation of the images at the subsequent steps. 
     At Step S 4 , the physician specifies the series D 1  for interpretation of the images in the series D 1  alone while using the terminal  5 , and transfers all the images of the series from the server  3  to the terminal  5 . The physician displays the first image Im 1 _ 0 , and continues to carry out image interpretation by display of a subsequent one of the images Im 1 _ 1  and son on in the same series D 1  if no images of other series are necessary for reference. 
     In the case where the physician judges that comparison with an image obtained in the past is necessary for interpretation while interpreting an image Im 1   —   x  in the series D 1  at Step S 4 , the physician searches for the series radiographed in the past. The physician then instructs the server  3  to transfer the series to the terminal  5  (Step S 5 ). 
     At Step S 6 , whether the series D 1  has been related to the series D 0  is confirmed. In the case where the series D 1  has not been related to the series D 0 , the server  3  starts transfer of the series D 0  starting from the first slice image (Step S 8 ). 
     In the case where the series D 1  has been related to the series D 0 , the server is notified that the series to be transferred to the terminal  5  is the series D 0  and that the image being displayed on the terminal  5  is the image Im 1   —   x  belonging to the series D 1  (Step S 7 ). 
     At Step S 9 , the server  3  determines one of the images that belongs to the series D 1  and corresponds to the image Im 1   —   x,  based on the information obtained at Step S 7  and a result of relating at Step S 3 . Assume that an Image Im 0   —   y  has been determined to be the corresponding image. In the case where none of the images in the series D 0  has been judged to correspond to the image Im 1   —   x,  the fact is displayed on a screen of the terminal  5  to cause the physician to select whether or not to transfer the series D 0  to the terminal  5  (Step S 10 ). 
     After the corresponding image has been determined, in what order the images in the series D 0  are transferred from the server  3  to the terminal  5  is determined at Step S 11 . In this case, the images are transferred in the order starting from the image Im 0   —   y  determined at Step S 7  followed by Im 0 _( y+ 1), Im 0 _( y− 1), Im 0 _( y+ 2), Im 0 _( y− 2), and so on that are closer to the image Im 0   —   y.  In this example, all the images in the series D 0  are transferred without limiting a range of the transferred images. However, the transfer range may be set in advance in a menu screen or the like so that only a portion of the images corresponding to the range in the series D 0  can be transferred. As a method of setting the transfer range, a method of specifying the quantity such as “20 images around the corresponding image” or a method of specifying an actual distance such as “slice images within 20 mm from the corresponding image” may be used. 
     At Step S 12 , the images are finally transferred to the terminal  5  according to the order determined at Step S 11 . The terminal  5  displays the image Im 0   —   y  immediately upon completion of transfer of the image. 
     As has been described above, according to this embodiment, when the series D 0  corresponding to the series D 1  being displayed on the terminal  5  is transferred from the server  3 , the series D 0  is transferred starting from the image corresponding to the image being displayed on the terminal. Therefore, the physician carrying out image interpretation on the terminal  5  can display and compare the image for interpretation after waiting for transfer of only the corresponding image. In addition, if the transfer range is limited in the above manner, a transfer load can also be reduced. 
     In the first embodiment described above, the radiographer manually searches for and determines the corresponding series at Step S 3 . However, a relationship between the series to be related to each other may be preset so that the corresponding series can be determined automatically according to a condition representing the relationship. For example, the condition may be set to relate the series of the same patient obtained by the same modality so that the system can determine that the series D 1  is related to the series D 0  at the time the series D 1  is transferred to the server  3 . Furthermore, the system may be set to relate series of the same patient obtained by different modalities. Moreover, a condition other than the patient and the modalities may also be used to determine the necessity of relating. 
     In the first embodiment, the images are related to each other at Step S 3 , and the result is stored. However, an apparatus to manually correct the result may be incorporated. In this manner, the case where the result of relating is wrong can be dealt with, and the result can also be deleted in the case where no corresponding image exists due to different radiography ranges between the series. 
     In the embodiment described above, the combinations with the corresponding images in the series D 0  are found for all the images in the series D 1  at Step S 3 . However, the combination may be found for only one of the images so that the remaining images can be related based on the combination. Tomographic images radiographed by modalities such as CT and MRI are obtained at predetermined slicing intervals, and the intervals can be easily obtained in many cases. Therefore, once the image in the series D 0  corresponding to one of the images in the series D 1  is found and the combination is stored, the images corresponding to the remaining images in the series D 1  can also be found easily in the series D 0 . For example, based on image relating information that an image Im 1   —   j  in the series D 1  corresponds to an image Im 0   —   k  in the series D 0  and information that the slicing intervals are 2 mm for the series D 1  while the intervals are 1 mm for the series D 0 , an image Im 1   —   j+n  can be easily related to an image Im 0   —   k+ 2n. In this manner, the corresponding images may be found according to the relating information of one combination and the slicing interval information. 
     In the embodiment described above, the series corresponding to the series D 1  is searched for manually by the physician to specify the series D 0  at Step S 4 . However, without direct specification of the series D 0 , the series may be determined according to a preset rule. In this case, the relationship between the series to be regarded as the corresponding series is specified in advance in a setting screen or the like. For example, in the case where the system has been set to relate the series of the same patient obtained by the same modality, the corresponding image group can be transferred in the determined order of the images by a simple click of a “Compare” button during image interpretation. In the case where a plurality of image groups are related to each other, the order of transfer may be determined by collectively combining images whose transfer has been determined among the image groups. For example, assume that series D 2  and D 3  correspond to the series D 1  being displayed on the terminal  5  and the series D 3  was radiographed before the series D 2 . In the case where an image Im 2   —   y  in the series D 2  and an image Im 3   —   z  in the series D 3  have been judged to correspond to the image Im 1   —   x  being displayed on the terminal  5 , the order of transfer from the server  3  may be determined as Im 2   —   y,  Im 3   —   z,  Im 2 _( y+ 1), Im 3 _( z+ 1), Im 2 _( y− 1), Im 3 _( z− 1), Im 2 _( y+ 2), Im 3 _( z+ 2), Im 2 _( y− 2), Im 3 _( z− 2), and so on. 
     In the above embodiment, the image transfer starts by manual specification of the series D 0  at Step S 5 . However, the transfer may be started automatically through judgment of a state of the terminal. For example, in the case where no operation has been carried out for a certain amount of time during interpretation of an image Im 1   —   a  of the series D 1  on the terminal  5 , the system may start transfer of the series that has been automatically determined to correspond to the series D 1  in the order starting from and closer to an image corresponding to the image Im 1   —   a.  Consequently, at the time of manual instruction by the physician (an operator of the terminal) to transfer the images for comparison, a portion or all of the necessary images has/have been transferred to the terminal. Therefore, the time necessary for display of the images for comparison can be shortened further, which leads to improvement in efficiency of image interpretation. Moreover, if the system checks a state of communication path to determine the timing of the transfer, efficiency of communication load can also be improved. 
     In the above embodiment, the order of transfer of the images in the series D 0  has been determined as the order starting from and closer to the image Im 0   —   y  at Step S 11 . However, the image that is going to be necessary may be judged and prioritized in determination of the order, based on a history of display of the series D 1  on the terminal  5  at Steps S 4  and S 5 . For example, in the case where the image interpretation of the series D 1  has been carried out at Steps S 4  and S 5  in sequential order such as Im 1 _ 0 , Im 1 _ 1 , . . . and Im 1   —   x  starting from the side of the head toward the side of the lower limbs without returning, the images preceding the image Im 1   —   x  may be judged to have been interpreted. In this case, the order of transfer of the series D 0  for reference is determined as Im 0   —   y,  Im 0 _( y+ 1), . . . Im 0 _End (the last slice), Im 0 _( y− 1), Im 0 _( y− 2), Im 0 _( y− 3), . . . and Im 0 _ 0  (the first slice). 
     In the example described above, the CT images are used. However, the same processing can be carried out on images of MRI (Magnetic Resonance Imaging) or PET (Positron Emission Tomography), for example. If mutual information is used to calculate the similarity, images obtained by different modalities such as CT and MRI can be related to each other. Therefore, the present invention can be effective for display and comparison of the images obtained by different modalities. 
     In addition, not only for the case of tomographic images such as CT or MRI images but also for the case where frontal or side images of CR or DR are stored as one series, the present invention is likewise effective. 
     The operation of a second embodiment of the present invention will be described next. 
       FIG. 5  is a schematic block diagram showing the configuration of a data transfer system of the second embodiment. As shown in  FIG. 5 , the data transfer system of the second embodiment is a network system for digital images, and comprises an image server  11  and an image display/correction terminal  13 . The image server  11  stores groups of digital images obtained by photography of the same main subject (such as a person) in the same time period by a plurality of digital cameras. The image display/correction terminal  13  is connected to the image server  11  via a network  12 . 
     In this embodiment, one image group refers to images obtained by one digital camera and is called as a series. Series D 10  and D 11  respectively comprise images obtained by a digital camera  110  and by a digital camera  111  in the same time period and at the same place. The series D 10  includes images Im 10 _ 1 , Im 10 _ 2 , Im 10 _ 3 , and so on while the series D 11  includes images Im 11 _ 1 , Im 11 _ 2 , Im 11 _ 3 , and soon. In each of the series, the images have been sorted in ascending order of photography time. Assume that image data of the series include not only pixel value information but also information on the time of acquisition of each of the images. 
     In image correction processes that will be described below, an operator targets all the images obtained by the digital camera  110 . The operator firstly transfers all the images in the series D 10  from the server  11  to the terminal  13 . The operator displays one of the images in the series D 10  to carry out desired image processing thereon. After completion of the image processing, the operator carries out image processing on a subsequent one of the images in the series. By repeating the processes, the operator carries out appropriate image processing on all the images in the series, and stores the images having subjected to the processing in the server  11 . As the image processing, red-eye correction and dynamic range compression may be carried out, for example. If the image processing to be carried out can be determined solely based on the image being displayed, the processing can be determined without a problem. However, if appropriate image processing is not known due to the fact that a structure of the subject in the image being displayed is not easily viewed in detail, for example, the same subject is highly likely to have been photographed in a corresponding one of the images obtained by the digital camera  111  at a time close to the time of photography of the currently displayed image. Therefore, by referring to the image photographed by the digital camera  111 , the appropriate image processing can be determined. 
     The images obtained by the digital camera  110  are transferred directly to the server  11  to be stored therein. The images obtained by the digital camera  111  are transferred to the server  11  via a terminal  14 , and stored therein. 
     The operation of the second embodiment in the above situation will be described below.  FIG. 6  is a flow chart showing the processing carried out in the data transfer system in the second embodiment. 
     The images obtained by the two cameras are respectively stored as the series D 10  and D 11  in the server  11  at Step S 21 . 
     At Step S 22 , the operator having transferred the images from the digital cameras to the server  11  notifies the server  11  that the series D 10  and D 11  have been obtained in the same time period and at the same place. 
     At Step S 23 , the operator transfers all the images in the series D 10  from the server  11  to the terminal  13  for image processing, and starts correction by using the images in the series D 10  alone. At Step S 23 , the operator carries out appropriate image processing on one of the images in the series D 10 . In the case where the image processing to be carried out has been determined based on the image alone, the operator carries out the processing and thereafter targets a subsequent one of the images. At the time of completion of image processing on the last image after repeating the processes, the processing ends. 
     In the case where the image processing to be carried out on an image Im 10   —   x  in the series D 10  has not been determined at Step S 23  based on the image alone, the operator specifies the series D 11  photographed by the other digital camera in the same time period and at the same place (Step S 24 ). Although the operator searches for and specifies the series D 11  in this case, a “Different Camera Images” button may be disposed on a screen so that the system can automatically search for and specify the series D 11  corresponding to the currently displayed series D 10  in response to a click on the button. 
     At Step S 25 , the time of acquisition of the image Im 10   —   x  being displayed on the terminal  13  is transferred to the server  11  together with the information of the series D 11  specified at Step S 24 . 
     At Step S 26 , a corresponding one of the images obtained at the closest time to the acquisition time transferred from the terminal  13  at Step S 25  is determined in the series D 11 . Assume that the image is Im 11   —   y.    
     At Step S 27 , in what order the images are transferred is determined regarding the series D 11 . The server  11  determines the order as Im 11   —   y,  Im 11 _( y+ 1), Im 11 _( y− 1), Im 11 _( y+ 2), Im 11 _( y− 2), and so on. Although all the images in the series D 11  are transferred in this case without limiting a range of the transfer, the transfer range may be set in advance in a menu screen or the like. In this case, a corresponding portion of the images to the range in the series D 11  is transferred. As a method of setting the transfer range, a method of specifying the quantity such as “20 images around the corresponding image in order of closer acquisition time” or a method of specifying the acquisition time such as “images obtained within 30 minutes from the acquisition time of the corresponding image” may be used. 
     At Step S 28 , the images in the series D 11  are finally transferred to the terminal  13  in the order determined at Step S 27 . The terminal  13  displays the image Im 11   —   y  as soon as the image has been transferred thereto, without waiting for transfer of the remaining images. 
     As has been described above, according to this embodiment, when the images in the series D 11  corresponding to the series D 10  being displayed on the terminal  13  are transferred from the server  11 , the images are transferred in the order of closer acquisition time to the image being displayed on the terminal. Therefore, the operator viewing and processing the images on the terminal  13  can determine the image processing through comparison of the images, after waiting for transfer of only the corresponding image. In addition, in the case where the transfer range has been preset, a transfer load caused by transferring an unnecessary portion of the images can be avoided. 
     In this embodiment, the images in each of the series are arranged in the ascending order of photography time, and the image closer in the acquisition time to the image currently displayed on the terminal is more prioritized in the transfer order. However, information specifying the subject may be used instead of the acquisition time. For example, specific characteristic quantities may be extracted in advance from the images and stored so that an image whose characteristic quantities are closer to those of the image being displayed on the terminal can be more prioritized in the transfer order.