EP0088125A1

EP0088125A1 - Method and apparatus for displaying corresponding images

Info

Publication number: EP0088125A1
Application number: EP19820903096
Authority: EP
Inventors: Donald E. Dick; Dina L. Elder; Fred S. Pfahler
Original assignee: LIFE IMAGING Corp
Current assignee: LIFE IMAGING Corp
Priority date: 1981-09-14
Filing date: 1982-09-10
Publication date: 1983-09-14
Also published as: WO1983000993A1

Abstract

Procédé et appareil d'affichage simultané d'images correspondantes, avec application particulière dans l'affichage d'images correspondantes du sein gauche et du sein droit d'une patiente. L'appareil comprend un premier moniteur TV (10) d'affichage d'images du sein gauche et un second moniteur TV (12) pour l'affichage d'images du sein droit. Un premier disque (19) dans lequel sont stockées des images du sein gauche communique avec le premier moniteur TV (10). Un second disque (16) sur lequel des images du sein droit sont stockées communique avec le second moniteur TV (12). Le premier et le second disques répondent chacun à un compteur d'images (20, 22) associé aux disques. Un circuit de commande (24) permet à l'opérateur de sélectionner différents modes de visualisation synchrone et séquentielle d'images correspondantes du sein gauche et du sein droit. Les images du sein gauche et les images du sein droit de la patiente sont normalement groupées en fichiers. Chaque fichier du sein gauche possède plusieurs images du sein gauche et chaque fichier du sein droit possède plusieurs images du sein droit. Des comparateurs supérieur et inférieur (75) permettent une mise en séquence en continu des images correspondantes des seins gauche et droit d'un fichier jusqu'à ce que l'opérateur interrompe la mise en séquence, par exemple de manière à regarder d'autres fichiers ayant des images correspondantes des seins gauche et droit. Une commande d'ajustement (90) est prévue pour permettre l'ajustement des compteurs d'images de sorte que, lorsqu'un fichier d'images de sein est sélectionné par l'opérateur, des images correspondantes des seins gauche et droit sont affichées par les moniteurs TV (10, 12).Method and apparatus for simultaneously displaying corresponding images, with particular application in displaying corresponding images of a patient's left and right breast. The apparatus includes a first TV monitor (10) for displaying images of the left breast and a second TV monitor (12) for displaying images of the right breast. A first disc (19) in which images of the left breast are stored communicates with the first TV monitor (10). A second disc (16) on which images of the right breast are stored communicates with the second TV monitor (12). The first and second disks each respond to an image counter (20, 22) associated with the disks. A control circuit (24) allows the operator to select different modes of synchronous and sequential viewing of corresponding images of the left and right breasts. The images of the left breast and the images of the patient's right breast are normally grouped into files. Each left breast file has multiple images of the left breast and each right breast file has multiple images of the right breast. Upper and lower comparators (75) allow continuous sequencing of the corresponding images of the left and right breasts of a file until the operator interrupts the sequencing, for example so as to watch other files with corresponding images of the left and right breasts. An adjustment control (90) is provided to allow adjustment of the image counters so that when a breast image file is selected by the operator, corresponding images of the left and right breasts are displayed by TV monitors (10, 12).

Description

METHOD AND APPARATUS FOR DISPLAYING CORRESPONDING IMAGES

Field of the Invention

The present invention relates to a method and appara- ⁰⁵. tus for displaying breast images of a patient who has undergone an ultrasonic breast examination. In particu¬ lar, the present invention provides a synchronized, se¬ quential, and simultaneous display of corresponding right . and left breast images of a patient.

0 Background Art

In U.S. Patent No. 4,233,988 to Donald E. Dic et al., issued November 18, 1980, and entitled "High Resolu¬ tion Rotating Head Ultrasonic Scanner", an ultrasonic scanner is described for use in examining the breasts of 5 a patient in order to detect possible breast carcinoma. This ultrasonic breast scanner obtains breast images which can be displayed on a TV monitor on a real time basis. The ultrasonic scanner conducts .an examination of a first breast and this is followed by an examination 0 of the second breast. As a consequence of this separate examination of the two breasts, images of only one breast are displayed at any one time during the examination process.

Although some pathological conditions can be found *5 in one breast by observing, the breast images of that breast alone, the capability of detecting early malignant conditions is significantly enhanced when corresponding left and right breast images are viewed at the same time. A comparison of corresponding right and left breast 0 images of the same patient more readily enables an iden¬ tification of early cancer by the doctor or other exam¬ iner. The doctor can easily observe similarities and variations between corresponding right and left _breast images. Based on variations between corresponding images and since it is highly unlikely that right and left breasts will have the same early malignancy, a diagnosis of a stage one carcinoma in one of the breasts can be made by the doctor with greater certainty.

The present invention provides a simultaneous dis¬ play of corresponding left and right breast images of the same patient. The left and right breast images are simul¬ taneously displayed on two TV monitors. The breast images are synchronously received by the TV monitors so that, at any instance- during the sequential display of the breast images, the right breast image corresponds to the left breast image. As a result, the doctor can identify any variation between the two corresponding breast images.

Disclosure of the Invention

In accordance with the present invention, a method and apparatus for displaying corresponding breast images are provided. The apparatus includes a video tape unit for inputting from video tape to disks TV video signals representing breast images. The disks communicate with first and second TV monitors so that the breast images can be viewed by the doctor or any other observer. A first disk sotres left breast images while a second disk stores right breast images. Two breast image counters input image numbers or address codes to the disks so that selected breast images can be obtained from the disks and displayed on the TV monitors. The image counters are controlled by means of a user controlled circuit. The user controlled circuit is controlled by the operator or user of the apparatus. The user may select a number of available options with each option defining a specific manner for viewing the breast images. An adjusting circuit is connected to the image counters. An adjusting circuit is required since the left and right breasts of the same individual are often not of the same size. As a result, more left breast images may be obtained, for example, than right breast images during the examination. It is likely then that an image of the left breast nipple center is stored on a first disk track different than the track of the second disk on which the right breast nipple center image is stored. Since it is highly important that corresponding left and right breast images be viewed and compared at all times, it may be necessary to access different disk tracks in order, to provide corresponding breast images. The adjusting circuit, together with an input provided by the user of the present invention, maintains corresponding breast images on the

TV monitors through adjustment of the image counters. The adjusting circuit outputs an adjusting step or pulse to one of the. image counters in those instances when the left breast images to be viewed do not correspond to the right breast images. The adjusting step modifies the image counter until the image number output therefrom - represents a breast image which corresponds^' to the other of the two breast images.

Upper and lower limit comparator circuits communi¬ cate with the image counters. Breast images are obtained and stored on the video tape in files of images. There is a number of breast images for each left breast file and each right breast file. For each file of left breast images, the apparatus requires a file of corresponding right breast images in order to display corresponding breast images. It is desirable to view the breast images sequentially in order to maximize the early malignancy detecting capability. Consequently, images within a •file are accessed sequentially in an increasing direction

OM WI or, alternatively in a decreasing direction. When either of the two ends or limits of one of the two files of corresponding breast images is reached, the upper or lower limit comparator circuits output a direction signal which reverses the direction of both image counters so that the counters begin to count in a direction opposite that of the previous count. As a result, the same breast image file is accessed for displaying breast images until the user interrupts the display and selects another breast image file for display.

In a method of obtaining corresponding left and right breast images, the user of the present invention inputs left and right breast images to the disks. The first TV monitor displays a left breast image of one of the files of breast images stored on the first disk. The user continuously accesses only the corresponding right breast image file on the second disk until the right breast image corresponding to the displayed left breast image is found and displayed on the second TV monitor. The dual mode is then enabled so that any difference in image numbers of the displayed corresponding left and right breast images is determined and stored in the apparatus. Corresponding left and right breast images of corresponding files can then be simultaneously, sequentially and syn- chronously displayed on the two TV monitors. The appara¬ tus is again-enabled in order to change or switch to other corresponding breast image files for viewing the corresponding images- thereof. This switching to another file triggers an adjustment of one of the image counters, if corresponding images are not initially displayed, until corresponding lef and right breast images are displayed. As before, the user is then able to view corresponding images of the newly accessed file of breast images. In view of the foregoing, a number of advantages of the present invention are readily discerned. A method and apparatus are provided for the simultaneous viewing of corresponding left and right breast images which were previously obtained during a breast examination. The doctor can compare right and left breast images to more easily diagnose an early malignant condition in one of the breasts of the patient. The present invention also provides sequential and synchronous visual displays so that the doctor can compare corresponding left and right breast images as a number of images are., displayed in a predetermined fashion. The apparatus also assures that corresponding breast images are displayed when the number of left breast images is not the same as the number of right breast images. Also, when the left and right breasts are different in size so that corresponding breast images are not located on the same disk track, the present invention adjusts the addressing to one of the disks to provide a display of corresponding left and right breast images.

Additional advantages of the present invention will be readily seen from the following description taken in conjunction with the accompanying drawings.

Brief Description of the Drawings

Fig. 1 is a block diagram showing the present inven- ^• tion;

Fig. 2 is a schematic drawing showing more detailed features of the user controlled circuit of the present invention;

Fig. 3 is a schematic drawing showing in more detail the latch network, multiplexer network and upper-lower limit comparator network of the present invention; and

•Fig. 4 is a schematic drawing showing in more detail. the adjusting circuit of the present invention. Description of the Embodiments

In accordance with this invention, a method and an apparatus for displaying corresponding images and, in particular, corresponding left and right breast images is provided. In order to facilitate understanding of a use of the present invention, U.S. Patent No. 4,233,988 to Dick et al. , issued November 18, 1980 and entitled "High Resolution Rotating Head Ultrasonic Scanner" is incorporate herein by reference. Although in order to understand the present invention the following description is directed to hardware,,circuits, it is appreciated that certain features of the present in¬ vention can be implemented using a microprocessor and appropriate software instructions. A computer program stored on EPROMs (Erasible Programable Read Only Memories) for execution on a COMMODORE Model Number 6502 micro¬ processor and used in implementing the method of the present invention has been devised and is set forth in the microfiche appendix filed with this application. As represented in the block diagram of Fig. 1, the apparatus includes a first conventional TV monitor 10 and a second conventional TV monitor 12. The monitors 10, 12 receive video signals stored on disks 14, 16 to display breast images. First or left disk 14 receives left breast images while second or right disk 16 receives right breast images. It is understood that this arrangement can be reversed with the left breast images stored on disk Ϊ6 and right breast images stored on disk 14. A video tape unit 18, which can be a conventional video tape player and recorder, inputs the TV video signals to the disks 14, 16 upon activation of the video tape unit 18 by the user or operator of the apparatus. In the pre¬ ferred embodiment, each disk has three hundred tracks. A single breast image is stored on one track. In a typical examination of one breast of a patient by the breast scanner disclosed in U.S. Patent No. 4,233,3 fewer than 300 breast images are obtained and stored on a breast scanner disk. At the completion of an examination of one breast, the breast images stored on the breast scanner disk are saved on video tape. The other breast of the patient is then examined and these breast images are also stored on the breast scanner disk during the examination. Again, these breast images are saved on video tape at the completion of the examination.

An examination of a breast of a^•pa'tient is conducted by the breast scanner as it moves in a head-to-foot direction relative to the patient whose breast is being scanned. Normally, during an examination of each breast of a patient, a number of files of breast images are obtained. A file of breast images can also be described as a set of scans wherein one scan corresponds to one breast image. In the usual examination of one breast, a first file of breast images is obtained in the form of a set of compound scans. A second file of breast images is obtained in the form of a set of single sector lateral scans. A third file of breast images is obtained in the form of a set of single sector medial scans.

In compound scans, breast images are obtained using both scanning heads of the .breast scanner of U.S. Patent No. 4,233,304 and the images are combined to provide a composite image. In' single sector lateral scans, only the transducers of the scanning head located at a rela¬ tively greater lateral distance from the longitudinal center axis of the patient are energized to obtain single sector breast images. In single sector medial scans, only the transducers of the scanning head located rela¬ tively more adjacent the longitudinal center axis of the patient are energized to obtain single sector breast images.

<<£\JKE OM When the user of the apparatus desires to view the breast images obtained as a result of the various scans, the breast images stored on the video tape are inputted to the disks 14, 16 by means of the video tape unit 18. Connected to each of the disks 14, 16 is a breast image counter 20, 22, respectively. Each image counter 20, 22 is a standard up/down counter for receiving a clock signal which increments or decrements the count, depending upon the state of a direction signal applied to the up/down input thereto.

A first or left image counter 20 inputs left image numbers to first disk 1^"4. Each left image number_^correspon to one of the left disk tracks. The left image number inputted to the first disk 14 permits the display on TV monitor 10 of the left breast image stored on the track having that left image number. Likewise, the second or right image counter 22 inputs right image numbers to second disk_-16. Each right image number corresponds to one of the right disk tracks so that the disk 16 is also addressed or accessed for providing a display of right breast images. Outputs of a user control circuit 24 are applied to the image counters 20, 22 in order to incre¬ ment or decrement the output count thereof. As illus¬ trated in Fig. 2, the user control circuit 24 includes a number of user controlled options for updating the count and thereby selecting the mode of breast display on the TV monitors 10, 12. The user control circuit 24 includes a standard keyboard defined as a user control unit 26. The user engages keyboard keys to enable predetermined controls and modes of display.

A sequence mode is provided to permit a display of a file or a set of scans of left breast images and a correspo ding file or a set of scans of right breast images in an automatic, sequential manner. After an end or last image

-- Έ

OM on one of the breast image files is displayed, the direc¬ tion of sequencing is reversed so that the same file of breast images is sequentially accessed and displayed again but in the opposite direction. A step mode permits the user to hold or freeze each breast image before sequencing to the next image by enabling the appropriate keyboard key each time a display of the next breast image is desired. The step mode includes sequencing in both an increasing direction wherein the image numbers outputted by the enabled image counter 20 and/or 22 are incremented and a decreasing direction wherein the image numbers outputted by the enabled image counters 20 and/or 22 are decremented. The selection of the disks 14 and/or 16 to be accessed using the sequence and step display modes are also user controlled. Both disks 14, 16 can be accessed at the same time or, alternatively, only one of the disks 14, 16 could be sequentially accessed.

A clock or frequency generator 28 produces the necessary clock pulses to step the image counters 20, 22 when in sequential mode. The clock pulses are applied to a frequency divider 30 which is also user controlled.. The user selects the desired rate at which the breast images are to be displayed. In the preferred embodiment, the clock outputs a sixty Hertz (Hz) pulse signal and the frequency divider 30 is able to reduce the rate of sequenti display by factors of 2, 3, 4, 6, 8, 12, 30, or 60. The sixty Hz signal is also used in adjusting the output of the image counters 20, 22, which will be discussed later. ^• τfi^"e clock pulse output from the frequency divider 30 is sent to AND gate 32. The clock pulses are outputted from AND gate 32 to OR gate 34 whenever the sequence mode is enabled. The logic HIGH pulse output of OR gate 34 is applied, through one or both of the OR gates 36, 38, to the clock input of the desired image counter 20 and/or 22, depending upon the disk selection input to AND gates 40, 42.

When in the step mode, a clock pulse is generated by the user through OR gate 34 by means of the activation or ^" depressing of the appropriate keyboard key. This clock pulse is then gated to the desired image counter 20 and/or 22 for addressing one or both of the disks 14, 16. A further user controlled option is illustrated which permits the selection of the TV monitor 10, 12 for, displaying the breast images. Left breast images may be viewed on TV monitor 10 or 12 depending ipon the state of switch 44. Right breast images are then displayed on the other of the two TV monitors 10 or 12. The TV monitors 10, 12 may also display instructions to the user of the apparatus.

Referring now to Fig. 3, the video tape containing TV video signals of the breast images also includes a synchronizing signal. As the TV video signals representing the breast images are sent to the disks 14, 16, the synchronizing signal is also outputted by the video tape. The synchronizing signal is a series of strobes or pulses with each strobe indicating that a new breast inage is being inputted to one of the disks 14, 16. The strobes are transmitted to OR gate 34 for updating the user selected image counter 20 or 22, depending upon the disk then being loaded, to thereby access a different disk track as each breast image is inputted.

The synchronizing signal is also applied to a counter and decoder circuit 46. At the end of each set of breast scans, which indicates the completion of a file of breast images,---the duration between the last strobe of the previously inputted image in the file and the first strobe of the next image in the file is about twice the^' time between strobes in one file. The counter and de¬ coder circuit 46 recognizes this double duration between strobes and outputs a latch signal when it occurs. The latch signal includes four bits of information for

O indicating which of sixteen breast image files is to be latched. The latch signal outputted by the counter and decoder circuit 46 is sent to both a left disk switch 48 and a right disk switch 50. Left disk switch 48 is

05 closed when left disk 14 is being loaded with breast images. Right disk switch 50 is closed when left disk 50 is being loaded with breast images.

The latch signal is outputted by the enabled switch 48 or 50 and applied to an addressable latch network 52,

10 as illustrated in Fig. 1. The addressable latch network includes two addressable latch circuits "54, 56.* The addressable latch circuit 54 receives left image numbers outputted by the image counter 20. The. addressable latch circuit 56 receives right image numbers outputted by ¹ _. image counter 22. The addressable latch circuits 54, 56 store image counter numbers representing lower image numbers of left and right breast image files using the latch signal generated by the counter and decoder circuit 46. A lower image number is the image number of the

20 first breast image in a file. Addressable latch circuit 54 stores lower image numbers of left breast image files. Addressable latch circuit 56 stores lower image numbers of right breast image files. The two addressable latch circuits 54, 56 are capable of storing sixteen lower

•^**> c ,

^■***-^• image numbers. Sixteen files of breast images for each breast of one patient can therefore be inputted to each of the disks 14, 16, provided that the total number of images of any one breast does not exceed three hundred images. 0 At the end of the loading of a file of breast images and the beginning of the loading of another file on one of the disks 14, 16, the image number then being applied to the addressable latch circuits 54, 56 is stored in the proper location of the addressable latch circuit 54 or 5 56, which is then enabled by the latch signal. At the

s completion of loading all of the left and right breast image files for one patient onto the disks 14, 16, the addressable latch circuits 54, 56 have stored lower image numbers representing the beginning or lower image for each of the breast image files.

The outputs of the addressable latch circuits 54, 56 are applied to a multiplexer network 58, as depicted in Fig. 1. The multiplexer network 58, comprises four multiplexers 60-66, as shown in Fig. 3. A tab signal is sent to the multiplexers 60, 64. The tab signal is out¬ putted by a tab counter 68. The tab signal controls the output of the multiplexers 60, 64. The tab signal includes four bits with the state of the four bits controlling the selection of one of the sixteen breast image files to be accessed from each of the disks 14, 16.

A tab plus one signal is sent to multiplexers 62, 66. The tab plus one signal is outputted by tab incre¬ ment 70 which adds one to the magnitude of the tab signal. Similar to the tab signal, the tab plus one signal controls the output of multiplexers 62, 66. However, since the tab plus one signal is a magnitude of one greater than the tab signal, multiplexers 62, 66 output the lower image numbers of the next file of breast images. These next in sequence lower image numbers outputted by multi- plexer 62, 66 are applied to image number decrements 72, 74 respectively. Image number decrements 72, 74 may include a down counter with appropriate logic to strobe in the next upper or lower image number and then count down by one each time a new tab file is accessed. Each image number decrement 72, 74 subtracts one from the magnitude of the inputted lower image number. The outputs of the image number decrements 72, 74 represent upper image numbers of the file of breast images then being accessed. An upper image number is the image number of the last breast image in a file. The lower and upper image numbers of the selected left and right breast files are inputted to an upper- lower comparator circuit 75, as represented in Fig. 1. As seen in Fig. 3, the upper-lower comparator circuit 75 includes four comparator circuits 76-82. Multiplexers 60, 64 communicate with comparators 76, 80 while image number decrements 72, 74 communicate with comparators 78, 82.

The left-image number currently outputted by image counter 20, together with the lower image number of the selected breast image file of lef disk 14, are inputted to domparator 76. This same left image number is also inputted to comparator 78, together with the upper image number of the selected breast image file of left disk 14 as represented by the output of image number decrement 72. Similarly, the right image number currently, out¬ putted by image counter 22, together with the lower image number of the selected breast image file of right disk 16, which has the same file number as the left disk 14, are inputted to comparator 80. This same right image number is also inputted to comparator 82, together with the upper image number of the selected breast image file of right disk 16 as represented by the output of image number decrement_.74. When the left image number outputted by image counter 20 is less than or equal to the lower image number of the file being accessed on left disk 14, a logic HIGH is transmitted to OR gate 84. A logic HIGH is also sent to OR gate.84 when the right image number outputted by image counter 22 is less than or equal to the lower image number of the file being accessed on right disk 16.

^* g 3 R o. When the left image number output from image counter 20 is greater than or equal to the upper image number of the file being accessed on left disk 14, a logic HIGH is applied to OR gate 86. A logic HIGH is also applied to OR gate 86 when the right image number outputted by image counter 22 is greater than or equal to the upper image number of the file being accessed on right disk 16.

The output of OR gate 84 is transmitted to the set input of direction flip-flop 88. The output of OR gate 86 is transmitted to the reset input of direction flip- flop 88. The Q or direction signal output of direction flip-flop 88 is sent to the up/down input of each-of the image counters 20, 22. The direction signal determines whether the output of the image counters 20, 22 is in- creased or decreased upon the receipt of a clock pulse inputted thereto.

The present invention further includes an adjusting circuit 90. As shown in Fig. 1, the adjusting circuit 90 communicates with the image counters 20, 22 and the upper-lower comparator circuit 75. Referring to Fig. 4, it is seen that the adjusting circuit includes subtracters 92, 94, 96. Subtracter 92 subtracts the lower image number of the selected file on the left disk 14 from the current left image number outputted by image counter 20. Subtracter 94 subtracts the lower image number of the selected file on the right disk 16 from the current right image number outputted by image counter 22. Subtracter 96 then subtracts the difference outputted by subtracter 94 from the difference outputted by subtracter 92 to provide.,. n offset signal. The offset signal outputted by subtracter 96 represents a difference or offset between the outputs of the two image counters 20, 22 and also includes any difference between the lower image number of the selected file on the left disk 14 and the lower image number of the selected file on the right disk 16. A difference arises in the output of the two image counters 20, 22 because there is often a difference in size between the left and right breasts of the same patient. As a result, the image number for a predeter- mined portion or section of the left breast may not be the same image number for the corresponding predetermined portion or section of the right breast. Further, there may be a different number of images in corresponding left and right breast image files. For example, the compound scan of the left breast may include 75 images while the compound scan.^"of the right breast may include 80 images. Because of this possibility of different left and right image numbers for corresponding breast images, an adjust¬ ment capability is provided to adjust one of the image counters so that the breast image represented by the output therefrom corresponds to the other of the two breast images.

When referring herein to breast images, "correspon¬ ding" means that each of the left breast images and each of the right breast images was obtained at substantially identical portions of the respective left and right breasts of the same patient. For example, a right breast portion located at the inferior portion of the right breast and located most adjacent a longitudinal axis located through the center of the patient corresponds to the left breast portion located at the inferior portion of the left breast and located most adjacent a longitudinal axis located through the center of the patient. Since it is highly important that corresponding left and right breast images be viewed simultaneously, sequential and synchronously on the TV monitors 10, 12, in order that a proper comparison of left and right breast images be made, any offset in image numbers must be determined and a compensation made. This will be subsequently explained in greater detail when the operation of the apparatus is discussed.

The offset signal outputted by the subtracter 96 is applied to comparator 98. When the output of subtracter 96 is greater than zero, a logic HIGH output from compara¬ tor 98 closes switch 100. The closure of switch 100 permits the sending of the offset signal to a latch circuit 102. When the offset signal is less than zero, switch 104 is closed by a logic HIGH outputted by com- parator 98. The offset signal is then sent to latch circuit 106. When either switch 100 or" 104 is open, zero is sent to latch circuits 102 or 106. Latch circuits 102 and 106 are updated when dual disk mode 124 is selected following single disk mode. The update occurs at the time of transition.

The outputs of latch circuits 102, 106 are applied to adders 108, 110, respectively. Also inputted to adder 108 is the lower image number of the selected breast image file on left disk 14. The lower image number of the selected breast image file on right disk 16 is inputted to adder 110.

The output of each of the adders 108, 110 is sent to comparators 112, 114, respectively. The current left image number from image counter 20 is also inputted to comparator 112 for comparison with the output of adder 108. The current right image number from image counter 22 is also inputted to comparator 114 for comparison with the output of adder 110- Tab flip-flop 116 is reset whenever^' the output of comparator 112 is equal to zero indicating that the magnitude of the output of adder 108 and the magnitude of the left image number are the same. Tab flip-flop 118 is reset whenever the output of com¬ parator 114 is equal to zero indicating that the magni¬ tude of the output of the adder 110 and the magnitude of the right image number are the same. When the output of comparator 112 or 114 is not equal to zero, a logic HI_GH is applied to AND gate 120 or 122, respectively. The A_ND gates 120, 122 also respond to the Q output of the ta_b flip-flops 116, 118, respectively. The tab flip-flops 116, 118 are set by a tab command signal which can be generated by the user of the apparatus when the user wishes to view another file of corresponding left and right breast images. The third input to each of the AND gates 120, 122 is the sixty Hz signal outputted by the frequency generator 28. When a pulse train output or adjust step from AND gate 120 or AND gate 122 is applied to OR gates 36 or 38, respectively, of Fig. 2, an offset signal having a magnitude other than zero is present and a tab command signal has been provided."* A logic HIGH output from OR gate 36 or OR gate 38 ^"updates image counter 20 or 22, respectively.

In order to fully understand the operation of the present invention and, in particular, adjusting circuit 90, a typical example of its application is provided. This procedure is followed for each patient, regardless of the number of files or sets of scans of breast images obtained during the examination. Since, in the usual ultrasound breast examination, a set of compound scans, a set of single sector lateral scans, and a set of single sector medial scans are made for each breast, the following discussion involves three files of breast images. It is readily understood that, in displaying corresponding breast images, the left breast file number is the same as the right breast file number.

For purposes of example,- assume 76 compound scan left breast images were obtained, 74 left breast single sector lateral scans were obtained, and 75 left breast single sector medial scans were obtained. ^"With respect to the^"right breast, assume 75 compound scan breast images were obtained, 77 single sector lateral scans were obtained and 71 single sector medial scans were obtained. It is also understood that the number of breast images depends upon the ability of the user to halt the scan whenever the inferior border of the breast is reached. As a consequence, the number of breast images obtained is often different for each of the files of the correspon¬ ding breast images, as this example indicates. At the completion of the three types of left breast scans by the ultrasonic breast scanner, three breast image files totalling 225 left breast images are trans¬ ferred from the ultrasonic breast scanner disk to video tape along with the logic image signal associated therewith. Likewise, three right breast image files totalling 223 images are transferred from the ultrasonic breast-scanner disk to the video tape along with the logic image signal associated therewith.

The video tape is transferred to the video tape unit 18 of the present invention when it is desirable to view corresponding left and-right breasts images. Through the^' assistance of user control, all of the left breast images are loaded on the left disk 14 and all of the right breast images are loaded on right disk 16. The first image on the video tape is stored on the first disk track. In this example, the left and right.breast compound scans are stored first on the disks 14, 16, respectively, while left and right single sector lateral and then single sector medial breast images are sub- sequently stored on their respective disks 14, 16. It is readily appreciated .that the arrangement of breast image storage according to the type of scan can be varied. That is to say, the compound scan breast images could be stored .subsequent to the single sector lateral scan breast images. It is necessary in this embodiment, though, that the types of scans for left and right breasts be stored in the same manner on their respective disks 14, 16. For example, if the left breast compound

O scans comprise the first file on left disk 14, the right breast compound scans must comprise the first file on right disk 16.

Together with the loading of left breast images from video tape to left disk 14, a latch signal is generated by the counter and decoder circuit 46, as previously " discussed, whenever the end of one file is reached and another file begins. The latch signal is applied to the addressable latch network 52 in order to store the lower image numbers then being outputted from image counters 20, 22. -

The image counters 20, 22 are updated by the tape strobe or pulse of the synchronizing signal which is present on the video tape and wherein each strobe indicates that another breast image is being stored. When left breast images are stored, AND gate 42 is not enabled so that only image counter 20 is incremented. Similarly, when right breast images are stored, AND gate 40 is not enabled so that only image counter 22 is incremented. with respect to the storing of lower image numbers for each of the breast image files in addressable latch network 52, the image number actually stored corresponds •to the number of the first pulse counted by the counter and decoder circuit 46 after decoding thereby of a double duration interval between strobes.

At the completion of the storing of left breast images on left disk 14, image counter 22 outputs an image number of 225 and image counter 22 outputs an image number of 223. In addition, file one of addressable latch circuit 54 has stored a lower image number of 1. File two of addressable latch circuit 54 has stored a lower image number of 77. File three of addressable latch circuit 54 has stored a lower image number of 151. File one of addressable latch circuit 56 has stored a lower image number of 1. File two of addressable latch circuit 56 has stored a lower image number of 76. File

OMPI three of addressable latch circuit 56 has stored a lower image number of 153.

In order to display corresponding left and right breast images on TV monitors 10, 12, user intervention is 5 required to first obtain at least one pair of correspon¬ ding left and right breast images. Preferably, the user accesses each of the disks until the left breast nipple center image is displayed on left disk 14 and the right breast nipple center image of the corresponding file is 0 displayed on right disk 16. The right breast nipple center images are chosen to facilitate the obtaining of corresponding left and right breast images by the user. It is understood that other corresponding images could initially be displayed by the user, but the certainty of *-* obtaining corresponding images is greater whenever the breast nipple center images are selected.

The user obtains corresponding images by stepping the desired image counters 20, 22 by means of the step mode previously discussed in order to display different 0 breast images, until the breast nipple center images are shown.

After corresponding breast images are initially obtained by the user and the user wishes to compare corresponding images, a dual mode key 124 on the key¬ 5 board of the user control unit 26 is enabled. As illus¬ trated in Fig. 4, the enabling of the dual mode produces a latch signal which holds the offset signal currently present at the output of subtracter 96 in either latch circuit 102 or latch circuit 106, depending upon whether 0 the offset signal is of a magnitude which is greater than zero or less than zero.

By way of example, assume the user has obtained corresponding nipple center breast images from file one and that the left breast nipple center image number is 36 5

OM - and right breast nipple center image number is 34. That is to say, when the user has completed the accessing of the disks 14, 16 in order to obtain corresponding breast images, the output of image counter 20 was 36 while the output of image counter 22 was 34. The numbers 36 and 34 are typical inasmuch as the breast nipple center image is obtained near the mid-portion of a set of scans by the ultrasonic breast scanner.

In order- to take into account any difference in the lower image numbers of the left and right breasts for the file then being accessed, subtracters 92, 94 are pro¬ vided. Subtracter 92 subtracts the lower image number (which in this example equals 1) of the left disk file being accessed from the current left image number out- putted by image counter 20, namely, an image number of 36, which corresponds to the left breast nipple center image. Similarly, subtracter 94 subtracts the lower image number (which in this example equals 1) of the left disk file then being accessed from the current image number outputted by image counter 22, which corresponds to the right breast nipple center image number of 34. The outputs of subtracters 92, 94 are applied to sub¬ tracter 96. In this embodiment, the output of subtracter 94 is subtracted from the output of subtracter 92 to produce the offset signal outputted by subtracter 96. In ; the given example, the offset signal has a magnitude of a positive two which is applied to comparator 98. Since this offset signal of two is greater than zero, switch 100 is._^closed. The offset signal of two is then coupled to latch circuit 102. When dual mode is then enabled by the user by means of the keyboard key 124, the offset of two is held in latch circuit 102.

At this time, the user is able to view on TV monitors 10, 12 corresponding left and right breast images which are displayed sequentially and synchronously according to the .mode of display selected by the user. For example, if the user wishes to compare corresponding breast images of file one in sequential mode, the sequence mode is enabled. Referring to Fig. 3, the output of tab counter 68 corresponds to file one in this example so that multi¬ plexer 60 outputs the lower image number of 1. Multi¬ plexer 62 outputs the upper image number of 76. Multi¬ plexer 64 outputs the lower image number of 1. Multi- • plexer 66 outputs the upper image number of 75. If the nipple center breast image 'numbers^' of 36 and 34 are still present, outputs of OR gates 84, 86 of Fig. 2 are each a logic LOW so that the Q output of direction flip-flop 88 remains the same. Assuming that the direction flip-flop is in the set state, the directional signal to each of the image counters 20, 22 causes the counters -20, 22 to increase or increment upon receipt of a clock pulse.

In sequence mode, the clock- pulses are applied to the image counters 20, 22 at the selected rate provided y the frequency divider 30 and corresponding breast images are sequentially, synchronously and continuously displayed on the TV monitors 10, 12. When the upper image number of 76 of file one of the left breast images is reached and displayed, the output of OR gate 86 becomes a logic HIGH. The logic HIGH resets the direction flip- flop 88 so that the direction of counting by image counters 20, 22 is reversed. Upon receipt of the succeeding clock pulses, each image counter 20, 22 is synchronously and sequentially decremented. As a result, the right breast image having an image number of 75 is not displayed.

This occurs because there are thirty-one left breast • images between the left breast nipple center image number of 36 and the upper left breast image number of 76 (in¬ clusive of the upper and center images) . In order that corresponding breast images be maintained, breast i ages obtained by the ultrasonic breast scanner at the relatively outer portions of one of the breasts might not be displayed.

The image counters 20, 22 continue to decrement upon receipt of clock, pulses until the image number of 1 of the right breast images is reached. The lower image number of 1 of the right breast images is reached before the lower image numbers 1 and 2 of- the left breast images are accessed because there are only seventy-three right breast images to be displayed in the decreasing direction (exclusive of the image just displayed when the- upper image of the left breast was reached) while there are seventy-five left breast images to be displayed in the decreasing direction (exclusive of the upper image just displayed) . As a result, the left breast images having the image numbers of 1 and 2 are not displayed. Once the lower image number of 1 of the left breast image file is reached, the output of OR gate 84 becomes a logic HIGH since the output of comparator 78 has become a logic HIGH. The direction flip-flop 88 is again set and the output therefrom causes the image counters 20, 22 to once again be incremented. From the foregoing, it is seen that in sequence mode corresponding breast images from correspon¬ ding breast image files are continuously accessed from the disks 14, 16 for display on the TV monitors 10, 12. The direction of display changes whenever one of the upper or lower image numbers of one of the two breast image files is reached. It has also been noted that one or more of the images obtained as a result of a scan might not be displayed during a corresponding image, dual mode display. The images not displayed are normally ob¬ tained outside the breast tissue and such images are rarely of any significance in diagnosing carcinoma in breasts. Also, unnecessary images may have been obtained because of operator inadvertence in failing to halt the breast scanning process after the outer portions of the breast had been scanned. With respect to step mode, the turnaround display is not provided. Rather, when the keyboard key for incrementing an image counter 20 or 22 is activated and the upper image number is currently outputted by that counter 20 or 22, the lower image of the next file is displayed. Similarly, when the keyboard key for decre¬ menting an image counter 20 or 22 is activated nd the lower image number is currently outputted by that counter 20 or 22, the upper image of the preceding file is displayed. This accessing of an adjacent file of breast images is accomplished by providing a logic HIGH to the appropriate OR gate 84 or 86. That is, the image counters 20, 22 continue to increment when a logic HIGH is applied to OR gate 84 while the image counters 20, 22 continue to decrement when a logic HIGH is applied to OR gate 86. Referring now to a discussion of the operation of the apparatus in sequence mode and when the user wishes to view corresponding breast images from another file, such as the second file, a tab command is applied to the tab counter 68 by user activation of the appropriate keyboard key to provide an output from the tab counter 68 corresponding to the second file. The lower image numbers for the second file of the disks 14, 16 are selected by the multiplexers 60, 64 and applied to the comparators 76, 80 connected thereto. The upper image numbers are outputted by the decrement circuits 72, 74 and applied to the comparators 78, 82 connected thereto. The offset signal having a magnitude of two remains held in latch circuit 102. The contents of latch circuit 102 or 106 is changed only by the user enabling the dual mode key 124. This enabling is provided when breast i age scans of another patient are to be viewed and not when switching between sets or files of scans of the same patient. The tab flip-flops 116, 118 of Fig. 4 are set by the tab command signal. The tab command signal also sets the direction flip-flop 88. The tab command signal also causes the lower image number for file two of the left breast images to be sent to the output of image counter 20. The lower image number for file two of the right breast images is sent to the output of image counter 22 as a result of the tab command signal.

In the given example, the lower image number for the left breast images of file two is 77. The lower image number for the right breast images of file two is 76. Upon receipt of the new lower image number of 77, adder 108 of Fig. 4 outputs a signal having a magnitude of 79 since the previously arrived at offset signal has a magnitude of two. Since the comparator 112 is^"comparing the magnitude of the output of image counter 20, which is 77, with the output of the adder, which is 79, a logic HIGH is outputted from the comparator 112 on the input line to AND gate 120 indicating that the output of com¬ parator 112 is not equal to zero. The Q output from the flip-flop 116 is also a logic HIGH since the tab command signal has set the tab flip-flop 116. A pulse train adjust step is outputted by the AND gate 120 when en¬ abled by the sixty Hz clock signal from frequency generator 28. The adjust step is applied to OR gate 36 of Fig. 2 and then inputted to image counter 20 where the image counter 20 is incremented so that the output thereof becomes 78. This output is, in turn, fed back to com¬ parator 112 of Fig. 4. Upon comparison, another adjust step is outputted since the left image number of 78 does not equal the output of adder 108 which remains at a magnitude of 79. The AND gate 120 once again generates an adjust step for incrementing image counter 20 when enabled by the clock signal and the output of the image counter 20 becomes equal to 79. Upon feeding the image counter 20 output of 79 to comparator 112, tab flip-flop 116 is reset since the comparison determined that the output from the adder 108 and the output from image counter 20 are now equal. As can be seen from this example, the number of pulses in the pulse train adjust step equals the magnitude of the offset.

At this time, image number 79 is outputted by image 0 counter 20 while image counter 22 outputs the -lower image number of 76 for file two of the right breast images. Accordingly, a left breast image having image number 79 is displayed on TV monitor 10 while a right breast image having image number 76 is displayed on TV monitor 12. One of the modes of display is then enabled by the user so that sequential, corresponding breast images from file two can be synchronously displayed.

From this discussion of the adjusting circuit 90, it is seen that the relative image location in file one and 0 file two of the left breast nipple center images are the same. That is, the left breast nipple center image for file two has an image number of 112. This image number is the 36th image of file two just as image number 36 represen the left breast nipple center image for file one. Similarl ^■*; the left breast nipple center image for file three has an image number of 186, which is the 36th image number from the lower image number of 151.

Likewise, the relative image location for files one and two of the right breast nipple center images are the 0 same. The right breast nipple center image number of file two is 110. The right breast nipple center image of file three is 187. Each of the right breast nipple center images is the 34th image from the beginning of the scan (lower image number) . As a result, corresponding breast images are displayed for the same patient, re¬ 5 gardless of the breast image file selected since the adjusting circuit 90 uses the offset output initially determined to change the display on one of the TV moni¬ tors 10, 12 before sequencing of images begins from the selected file of left and right breast images. 05 The previous discussion assumed that corresponding nipple center breast images were displayed using the first file of images. Any offset between corresponding image numbers can also be obtained when the user first displays corresponding nipple center breast images using •_Q any one of the breast image files. By way of example once again, assume the user displays corresponding nipple center breast images using the third file which comprises, single sector medial scans.' Since the left nipple center breast image is the 36th image from the first or lower _5 image in any one of the files in the given example, including the third file, a left breast image having image number 186 (lower image number 151 plus the 36th image of the third file) is displayed on TV monitor 10. Since the right breast nipple center image is the 34th 20 image from the first or lower image in any one of the files in the given example, including the third file, a right breast image having image number 186 (lower image number 153 plus the 34th image of the third file) is displayed on TV monitor 12. The difference between these 5 two image numbers is zero. However, the lower image numbers of the left and right breast files are not equal. The left breast, lower image has an image numbe of 151 while the right breast lower image has an image number of 153. This difference of two between the two lower image 0 numbers is obtained by means of subtracters 92, 94 together with subtracter 96 of Fig. 4. As can be seen, regardless of the file initially selected by the user to obtain the correspondence nipple center images, an offset output of a positive two is obtained. Although the present invention has been described for use in displaying corresponding breast images, it is understood that the present invention can be used to display corresponding images of other parts of the human anatomy, such as corresponding images of two kidneys of a patient. The apparatus described, herein can also be used to compare recently obtained images of a body organ with previously obtained images of the same organ. Further, the present invention has utility in any field wherein it is desirable to display images having some defined correspon dence therebetween for the purposes of comparison or deter¬ mining similarities or variations, for example.

The disks 14, 16 are Arvin disks, TV monitors 10, 12 are models VF02 made by the Conrac Company, video tape unit 18 is a Betamax SLO-323 made by Sony Corporation, and the Keyboard of the user control unit 26 is a Model LI648 made by the Key-Tronic Company. The Commodore Model No. 6502 microprocessor previously mentioned can be used with the foregoing hardware and the software set forth in the microfiche appendix, together with appropriate peripheral interface circuitry, in order to implement the present invention as described hereinabove. In view of the detailed discussion, it is seen that corresponding left and right breast images are synchronously and sequentially displayed on TV monitors to aid in the diagnosis of possible breast carcinoma. With the initial assistance of the user of the apparatus, corresponding left and right breast images are continuously displayed for each patient, regardless of the number of breast image^'s obtained, and stored on video tape during the breast examination of the patient. Without user inter¬ vention, the apparatus is able to change the breast image display of one TV monitor so that corresponding images are displayed whenever the user wishes to view another file of corresponding breast images. In addition, syn¬ chronous sequencing in both an increasing image number ^• direction and a decreasing image number direction is

•__ provided of corresponding breast images of corresponding breast image files to facilitate a comparison of breast images and minimize operator intervention.

Although the present invention has been described with reference to particular embodiments, it is readily understood that variations and modifications can be effected within the spirit and scope of this invention.

Claims

What Is Claimed Is;

1. Using digital circuitry and .a means for viewing, a method for displaying corresponding left and right breast images, comprising the steps ofi obtaining on the viewing means^" corresponding left and right breast images; and sequentially and synchronously controlling the viewing means for providing a continuous display^" of corresponding left and right breast images.

2. Using digital circuitry and a means for viewing, a method for displaying corresponding left and.-right breast images, each of the left and right breast images being represented by an image number, and in which the left breast images form at least two files of left breast images with each- of the two files having a plurality of left breast images, and in which the right breast images form at least two files of right breast images with each of the two files having a plurality of right breast images, the method comprising the steps of: displaying on the viewing means one of the left breast images of the first left breast image file and ^' displaying one of the right breast images of the first right breast image file, said one of the first file of left breast images corresponding to said one of the first file of right breast images; switching to a display of one of the left breast images of the second file of left breast images and one of the right breast images of the second file of right breast images; and changing the display of said one of the left breast images or right breast images of the second file of images to another one of the left breast images or right breast images of the second files of left and right breast images when there is a lack of correspondence between said one of the left breast images of the second file of left breast images and said one of the right breast images of the second file of right breast images. ^:

3. A method for displaying a plurality of correspon¬ ding irst and second images using memory means, com¬ prising the steps of: storing the plurality of first and. second images on memory means; displaying a first image; displaying simultaneously with the first image a second image corresponding to the first image; and synchronously and sequentially accessing the memory means so that corresponding first and second images are simultaneously updated and displayed.

4. A method for displaying corresponding first and second images of first and second image files, comprising the steps of: displaying a first image of the first file of first images; displaying simultaneously with ^*the first image a second image of the first file of second images correspon¬ ding to the displayed first image; switching in order to display corresponding first and second images of the second image files; and adjusting the display of at least one of the first or second images of the second file when a lack of correspon dence exists between the display of first and second images of the second file so that corresponding first and second images of the second file are displayed.

5. A method for displaying on memory means a plurality of corresponding first and second images, each of the...plurality of first images and the plurality of second images having a lower image number and an upper image number, comprising the steps ofs storing the plurality of first axjsl second images on the memory means; obtaining one of the first images_?- obtaining simultaneously witfe saiώ one of the first images one of the second images corresponding to said one of the first images; displaying in a sequential and synchronous manner corresponding first and second images in a first direction; changing to a display of corresponding first and second images in a second direction after an upper or lower image of the first images or second images is displayed? and displaying in a sequential and synchronous manner corresponding first and second images in a second direc- tion.

6. A method for displaying a plurality of correspond first and second images, each of the plurality of^*images being represented by an image number, each of the plurality of first and second images forming at least two files with each of the files having a plurality of images, comprising the steps of: obtaining one of the first images of the first file of images; obtaining simultaneously with said one of the first images^' of the first file of images one of the second images of the first file of second images, said one of the second images corresponding to said one of the first images; determining a difference in the image numbers between said one of the first images of the first file of first images and said one of the second images of the first file of second image^'s; displaying corresponding first and second images of the first files of first and second images in a sequential and synchronous manner;

^' displaying one of the first images of the second file of first images and one of the second images of the second file of second images; changing the display of the second file of second images from said one of the second images to another one of the second images of the second file using the deter-

O mined difference in imag numbers in order to display corresponding first and second images of the second files; and displaying corresponding first and second images of the second file of the first and second images in a sequential and synchronous manner.

•

7. .An apparatus for displaying corresponding images comprising: first means for storing a plurality of first images and a plurality of second images, at least some of the first images having corresponding second images; - second means for use in accessing said first means to select first and second images for display; third mean^'s responsive to said first means for displaying simultaneously a first image and a second image; a d fourth means for controlling.said second means to generate a sequential and synchronous display of correspond first and second images using said third- means.

8. An apparatus, as claimed in Claim 7, wherein: said first means includes a first disk and a second disk, said first disk storing the first images, said second disk storing the second images.

9. An apparatus, as claimed in Claim 7, wherein said second means includes: a first image counter for outputting first image numbers, each first image number representing one of the • first images; and a_^second image counter for outputting second image numbers, each second image number representing one of the second images.

10. An apparatus, as claimed in Claim 7, wherein said third means includes: first monitor means for displaying one of the first images; and second monitor means for displaying simultaneously with one of the first images a second image correspon¬ ding to the first image.

11. An apparatus, as claimed in Claim 7, wherein: the plurality of first images includes a first lower image represented by a first lower image number and a first upper image represented by a first upper image number and the plurality of second images includes a second lower image represented by a second lower image number and a second upper image represented by a second upper image number, said fourth means including means for modifying the direction of the display of first and second images whenever one of the first or second -lower image numbers or first or second upper image numbers is reached during, the sequential, synchronous and simul¬ taneous display of corresponding first and second images.

12. An apparatus, as claimed in Claim 7, further including: means for inputting video signals representing the first and second images to said first means, said in- putting means further providing a logic image signal for indicating when each image is being stored on said first means.

13. An apparatus for simultaneously, synchronously and sequentially displaying corresponding first and second images wherein the corresponding images include a plurality of first images and a plurality of second images, each of the first and second images having an image number, the plurality of first images including at least a first file of images and a second file of images, the plurality of second images including at least a first file of images and a second file of images, the apparatus comprising: means for displaying simultaneously corresponding first and second images; eans for controlling said displaying means to provide a sequential and synchronous display of corresponding first and second images; and means for adjusting said controlling means when a change is made from displaying corresponding first and second images of the first file to displaying first and second images of the second file and when a correspondence between the first and second images of the second file is absent.

14. An apparatus, as claimed in Claim 13, wherein: said adjusting means provides an offset signal having a magnitude other than zero when a correspondence between first and second images of the second file is absent after a change is made from displaying correspon¬ ding first and second images of the first file to display¬ ing first and second images of the second file.

15. An apparatus, as claimed in Claim 13, wherein: said controlling means includes means for modifying the direction of the display of first and second images of the first file whenever a lower or upper first or second image number is reached during the simultaneous,- sequential and synchronous display of first and second images of the first file.

16. An apparatus for displaying simultaneously corresponding left and right breast images in. a syn¬ chronous and sequential manner, the apparatus comprising: first means for displaying simultaneously correspondin right breast images ^'and left breast images, each of the left breast images represented by a left image number and each of the right breast images represented by a right image number; and second means for synchronously and sequentially controlling said displaying means so that a continuous and simultaneous display of corresponding left and right breast images is viewed by a user of the apparatus.

17. An apparatus, as claimed in Claim 16, wherein: said second means includes means for modifying the direction of sequentially displaying left and right breast images from a direction increasing the left and right image numbers to a direction decreasing the left and right image numbers.

18. An apparatus, as^' claimed in Claim 17, wherein said modifying means includes: means for latching lower ^"left and right image numbers; and means for continously comparing lower left and^'right, image numbers with current image numbers which represent the current display of corresponding left and right breast images.

19. An apparatus,- s claimed in Claim 18, further including: third means for inputting TV video signals repre¬ senting left and right breast images to said second means, said third means outputting latch signals to said latching means so that said latching means stores lower image numbers upon receipt thereby of a latch signal as the TV video signals are inputted to said second means.

20. An apparatus for displaying a plurality of corresponding left and right breasts images in a syn¬ chronous and sequential manner, the plurality of left breast images forming at least two files with each file having a plurality of left breast images and each file having left lower and left upper image numbers, the plurality of right breast images forming at least two files with each file having a plurality of right breast images -and each file having right lower and right upper image numbers, the apparatus comprising: first means for simultaneously displaying correspon¬ ding left and right breast images; second means for synchronously and sequentially controlling said first means so that a simultaneous display of corresponding left and right breast images is viewed by a user of the apparatus; third means communicating with said second means for selecting one of each of the left and right breast image files for display; and fourth means for adjusting the output of at least a portion of said second means to provide_corresponding left and right breast images of the second file using said first means. __.

21. An apparatus, as claimed in Claim 20, further including: means for latching lower left and right breast image numbers; and means communicating with said latching means for use in choosing one of the files of left and right breast images to be displayed and outputting the lower left and right breast image numbers of the chosen file.

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