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Description  |
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TECHNICAL FIELD
The invention relates generally to ultrasound imaging and more particularly
to a method and a system for measuring body structures using ultrasound
imaging.
DESCRIPTION OF THE RELATED ART
Ultrasound imaging systems are commonly used to measure various anatomical
features of a human fetus during fetal development. The measurements of
the anatomical features may include the femur length, the humerus length,
and the head circumference of the fetus. These measurements can be used to
determine the gestational age of the fetus. The gestational age can then
be used to assist in a diagnosis of the fetus with respect to
abnormalities by comparing the different measurements with established
values for that gestational age.
During an ultrasound examination using a conventional ultrasound imaging
system, measurement values are computed by examining a "freeze frame" of a
scanned ultrasound image displayed on a monitor of the system. The "freeze
frame" includes the anatomical feature of the fetus that is to be
measured. Typically, a line or an ellipse is drawn over the displayed
anatomical feature to measure the length or the circumference of the
anatomical feature. After the computation, the measurement value and the
corresponding ultrasound image that was used to compute the measurement
value can be independently stored in the system. Thus, storing both the
measurement value and the corresponding ultrasound image requires two
steps, one step to store the measurement value and another step to store
the corresponding ultrasound image. If the ultrasound image is not stored
at this time, that particular ultrasound image is generally discarded and
cannot be stored at a later time. For a specific anatomical feature of a
fetus, anywhere from three to six measurements are typically made.
Since the corresponding ultrasound image may not have been saved for each
stored measurement value, it may not be possible to verify, at a later
time, the measurement values that were selectively saved by a sonographer.
Specifically, a review of an outlying measurement value for a particular
anatomical feature of a fetus during an examination review may not be
possible due to the absence of a corresponding ultrasound image. An
outlying measurement value is a value that is extreme with respect to
other measurement values of the same anatomical feature. Even if the
ultrasound images were saved, the saved ultrasound images are not
correlated with the measurement values. Without such correlation, a review
of the saved measurement values can be difficult, since matching an
ultrasound image to the corresponding measurement value can be tedious.
For example, if a reviewer wants to examine an outlying measurement value,
the invalidation or verification of the outlying measurement value can
only be accomplished by an exhaustive review of all stored ultrasound
images.
In light of these concerns, what is needed is a method and a system for
storing and managing both the measurement values and their corresponding
ultrasound images to facilitate an efficient ultrasound examination and an
effective review of the saved measurement values and the ultrasound
images.
SUMMARY OF THE INVENTION
A method and a system for storing and managing dimensional measurement
values and the underlying ultrasound images utilize a report generator
that operates to generate an examination report of an ultrasound
examination having saved measurement values. The operations of the report
generator allow an expedient access to the corresponding ultrasound images
that were used to derive the measurement values. In addition, the report
generator operates to automatically save the ultrasound image when a
measurement value that was computed from that ultrasound image is saved.
This feature ensures that for each saved measurement value,.the
corresponding ultrasound image is also saved. The system utilizes
ultrasound waves to image various anatomical features of a patient or a
fetus. Examples of anatomical features that may be imaged by the system
include the femur, the humerus, and the fetus head. These ultrasound
images are used to compute measurements of the anatomical features.
The system includes an ultrasonic scanhead, a processing unit, an input
device, and a display device. The scanhead includes an array of
piezoelectric elements to transmit sound waves and to receive echoes of
the transmitted ultrasound waves that are reflected from an anatomical
feature of interest. The scanhead operates to convert the received echoes
into electrical signals. The scanhead is electrically coupled to the
processing unit, which generates an ultrasound image of the anatomical
feature from the electrical signals. The input device functions as a user
interface and may include a standard computer keyboard and a computer
mouse. The display device may be a CRT or an LCD monitor.
The processing unit of the system includes a scanhead controller, memory,
the report generator, a removable storage device, a network interface, and
a processor. The scanhead controller is operatively connected to the
ultrasonic scanhead to control the transmitting and receiving operations
of the scanhead. The removable storage device may utilize one of a number
of removable storage media that are currently available, such as a
writeable CD, a DVD, or a magneto-optical storage medium.
The report generator of the processing unit is configured to operate with
the processor to generate an examination report that can be displayed on
the display device. The report generator performs many of the procedures
that are necessary to generate the examination report. The report
generator may be implemented in the processing unit as hardware and/or
software. The report generator includes a measurement computer, an
automatic ultrasound image saver, a measurement-to-image associator, and a
data analyzer. The measurement computer operates to compute a dimensional
measurement of an anatomical feature depicted in an ultrasound image. The
automatic ultrasound image saver operates to automatically save an
underlying ultrasound image when a measurement value that was derived from
the underlying ultrasound image is saved during an ultrasound examination.
The measurement-to-image associator operates to link each measurement
value to its corresponding ultrasound image. The data analyzer operates to
derive an analysis based on the saved measurement values. The analysis may
indicate any abnormalities of the patient or the fetus that was examined.
In the case of a fetal examination, the data analyzer may determine an
estimated gestational age of the fetus.
The method in accordance with the present invention includes a step in
which an ultrasound image of an anatomical feature is captured using a
well known ultrasound imaging technique. Next, a dimensional aspect of the
anatomical feature depicted in the ultrasound image is measured using the
measurement computer to derive a measurement value. The measurement value
is then saved by a sonographer. In response to this saving operation, the
automatic ultrasound image saver of the report generator automatically
saves the ultrasound image to ensure that for each saved measurement
value, a corresponding ultrasound image is also saved. Additional
measurement values for the same anatomical feature and/or other anatomical
features of the patient or the fetus may then be derived and saved from
additionally captured ultrasound images.
After all the measurement values of interest and the corresponding
ultrasound images have been saved, an examination report is generated by
the report generator of the system. The examination report can be
electronically displayed on the display device of the system. The
examination report includes the saved measurement values and their
corresponding ultrasound images. In one embodiment, the examination report
contains a number of virtual buttons. Each virtual button is designated
with a specific measurement value. When a virtual button of a particular
measurement value is activated, the examination report that is displayed
on the display device is replaced with the ultrasound image that
corresponds to the particular measurement value. In an alternative
configuration, the corresponding ultrasound image is displayed in a
superimposed manner over the examination report when the virtual button is
activated, such that the corresponding ultrasound image and most of the
examination report are simultaneously visible on the display device. This
feature provides an efficient means to invalidate or verify any outlying
measurement values. In addition, this feature allows the viewer to
selectively examine only the ultrasound images that are of interest
without reviewing all the saved ultrasound images.
In another embodiment, the examination report includes a number of
hyperlinks that are associated with the measurement values, instead of
virtual buttons. The hyperlinks operate in the same manner as the virtual
buttons. When a hyperlink that is associated with a particular measurement
value is activated, e.g., by "clicking on" or "hovering" a cursor over the
hyperlink, the examination report that is displayed on the display device
is replaced with the ultrasound image that corresponds to the particular
measurement value. In an alternative configuration, the corresponding
ultrasound image is displayed in a superimposed manner over the
examination report when the hyperlink is activated.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram of an ultrasound imaging system in accordance
with the present invention.
FIG. 2 is a block diagram showing the components of a report generator
included in the system of FIG. 1.
FIG. 3 is a portion of an examination report having virtual buttons in
accordance with one embodiment of the invention that is displayed on a
display device of the system of FIG. 1.
FIG. 4 is an exemplary ultrasound image that is displayed on the display
device when one of the virtual buttons of FIG. 3 is activated.
FIG. 5 is a portion of an examination report having hyperlinks in
accordance with another embodiment of the invention that is displayed on
the display device.
FIG. 6 is a flow diagram of a method of storing and managing measurement
values, including corresponding ultrasound images, using the system of
FIG. 1.
DETAILED DESCRIPTION
With reference to FIG. 1, an ultrasound imaging system 10 in accordance
with the present invention is shown. The system operates to image various
anatomical features of a patient or a fetus during an ultrasound
examination by transmitting ultrasound waves and then receiving echoes of
the transmitted ultrasound waves that are reflected from an anatomical
feature being examined. Examples of anatomical features that may be imaged
by the system include the femur, the humerus and the head. These
ultrasound images are used to compute dimensional measurements, such as
femur length, humerus length and head circumference. The computed
measurements and their corresponding ultrasound images can then be saved
in the system to generate a report of the ultrasound examination. The
manner in which the computed measurements and the corresponding ultrasound
images are saved in the system ensures that for each saved measurement,
its corresponding ultrasound image is also saved. In addition, the
computed measurements and the corresponding ultrasound images are
incorporated into the examination report, so that a user can easily
navigate between the measurements to their corresponding ultrasound images
within the examination report.
The ultrasound imaging system 10 includes an ultrasonic scanhead 12, a
processing unit 14, an input device 16, and a display device 18. The
ultrasonic scanhead includes an array of piezoelectric elements that
generates ultrasound waves in response to electrical signals of proper
voltage and frequency. As is well known in the art, the piezoelectric
element array of the scanhead also generates electrical signals in
response to mechanical vibrations caused by return echoes of the
ultrasound waves. These return echoes are processed by the processing unit
14 to image an anatomical feature of interest.
The input device 16 may include a standard computer keyboard and a computer
mouse, as shown in FIG. 1. The input device 16 is used as a user interface
to control the functions of the system 10, such as initiating ultrasound
imaging, computing a measurement for a particular anatomical feature,
storing the computed measurement and the corresponding ultrasound image,
displaying an examination report on the display device 18, and navigating
through information incorporated in the displayed examination report. The
display device 18 may be a conventional computer monitor, such as a CRT or
an LCD monitor.
The processing unit 14 is designed to perform various signal processing
procedures that are required for proper operation of the system 10.
Included in the processing unit are a scanhead controller 20, memory 22, a
report generator 24, a removable storage device 26, a network interface
28, and a processor 30. The scanhead controller 20 is operatively
connected to the ultrasonic scanhead 12 to control the transmitting and
receiving operations of the scanhead. The memory 22 of the processing unit
may be a standard hard disk drive that is commonly found in a typical
personal computer. The removable storage device 26 may utilize one of a
number of removable storage media that are currently available, such as a
writeable CD, a DVD, or a magneto-optical storage medium. The network
interface 28 may include a modem or an ethernet card that allows the
system 10 to be connected to a network 32. The network may be any type of
network, such as a LAN, a WAN or the Internet.
The report generator 24 of the processing unit 14 is configured to operate
with the processor 30 to generate an examination report that can be
displayed on the display device 18. The report generator performs many of
the procedures that are necessary to generate the examination report. The
report generator may be implemented in the processing unit as hardware
and/or software. The report generator includes a measurement computer 34,
an automatic ultrasound image saver 36, a measurement-to-image associator
38, and a data analyzer 40, which are illustrated in FIG. 2. The
measurement computer 34 is configured to assist a sonographer in measuring
an anatomical feature in the displayed ultrasound image in a known manner.
For example, the sonographer may indicate two reference points at the
opposite ends of an anatomical feature, such as a femur of a fetus, that
is depicted in an ultrasound image. The reference points may be indicated
by using the mouse of the input device 16. After the two reference points
have been indicated, the sonographer activates a control on the input
device to initiate the measuring procedure. The activation signals the
measurement computer to draw a line connecting the two reference points
and to compute the length of the drawn line using predefined calibration
parameters.
The automatic ultrasound image saver 36 of the report generator 24 operates
to automatically save an ultrasound image when a corresponding measurement
value is being saved under the direction of the sonographer. Thus, for
each saved measurement value, its corresponding ultrasound image will also
be saved. This feature ensures that a reviewer of the ultrasound
examination can independently examine the underlying ultrasound image for
a questionable measurement value. In addition to the automatic image
saving feature, the measurement-to-image associator 38 of the report
generator allows the report generator to link the saved measurement value
with its corresponding ultrasound image, so that there is an association
between the measurement value and the image. The association of the
measurement value and the corresponding ultrasound image allows the report
generator to create an examination report in which the measurement value
and the corresponding ultrasound image are operatively coupled, such that
the ultrasound image corresponding to a particular measurement value on
the examination report can be found with a click of a button or a stroke
of a key on the input device 16, without the need to review a large number
of saved ultrasound images to find the desired ultrasound image.
The data analyzer 40 of the report generator 24 is configured to process
the measurement values that were saved and to derive an analysis based on
the measurement information. If a fetus was examined, the data analyzer
may determine an estimated gestational age of the fetus from the
measurement values. In addition, the data analyzer may indicate any
abnormalities of the patient or the fetus by comparing the measurement
values with established values for the particular size of the patient or,
in the case of a fetus, the particular gestational age of the fetus. The
analysis derived by the data analyzer is included in the examination
report that will be generated by the report generator. The examination
report, as displayed on the display device, will be described below.
FIG. 3 illustrates a portion of an examination report 42 for a fetus in
accordance with one embodiment of the invention. The report is generated
by the report generator 24 and is displayed on the display device 18. The
examination report is shown to include a number of measurement values of
the fetus that were computed during an ultrasound examination. Each
measurement value is displayed on one of several virtual buttons 44, 44A,
46 and 48. The virtual buttons 44 are dedicated to measurement values of a
femur length, while virtual buttons 46 are dedicated to measurement values
of the head circumference. In the preferred embodiment, a text string that
identifies a particular measurement value is also displayed on each of the
buttons. The text strings are preferably typed into the system 10 prior to
saving the measurement value during the ultrasound examination. In FIG. 3,
a cursor 50 is positioned over the button 44A, which is being "pressed."
The examination report 42 is configured to display an ultrasound image
when the button having the corresponding measurement value is pressed.
Therefore, the next screen that will be displayed on the display device
will include an ultrasound image 52 which was used to compute the 8.1 cm
femur length, which is shown in FIG. 4. In an alternative configuration,
the ultrasound image is displayed along with the examination report when
the corresponding virtual button is pressed, instead of replacing the
displayed examination report. As an example, the pressing of the virtual
button 44A may cause a reduced image of the ultrasound image 52 of FIG. 4
to be displayed over a particular region of the displayed examination
report 42 of FIG. 3 (e.g., next to the virtual button 44A), such that the
ultrasound image and most of the examination report are simultaneously
visible on the display device. Preferably, the text string that was
entered for the measurement value is also superimposed on the
corresponding ultrasound image. This feature of measurement-to-image
linkage allows a reviewer of the examination report to have almost an
instant access to the ultrasound images that correspond to the measurement
values in the examination report. Furthermore, since the report generator
automatically saves the underlying ultrasound image when a measurement
value is saved, the examination report will contain all the ultrasound
images that were used to compute the measurement values.
The virtual buttons 44, 44A, 46 and 48 of the examination report 42 of FIG.
3 may also include checkbox fields 54 that can be checked or unchecked. As
an example, the checkbox fields can be checked or unchecked by positioning
the cursor 50 over the checkbox field of interest. The checkbox fields
allow the operator of the ultrasound imaging system 10 to indicate the
measurement values and/or their corresponding ultrasound images of the
examination report that are to be sent to a destination, such as a remote
computer system (not shown), through a network.
FIG. 5 shows a portion of an examination report 56 for a fetus in
accordance with another embodiment of the invention. The report is
generated by the report generator 24 and is displayed on the display
device 18. The examination report includes the same measurement values
that were shown in the examination report 42 of FIG. 3. The examination
report 56 includes hyperlinks 58, 58A, 60 and 62 for the displayed
measurement value. A hyperlink is an underlined text string that is
commonly found on web sites on the Internet. Essentially, the buttons 44,
44A, 46 and 48 of the examination report 42 are replaced by the hyperlinks
of the examination report 56. In FIG. 5, the cursor 50 is positioned over
the hyperlink 58A, which is being "activated," as indicated by the
underlined text "femur length 004" shown in boldface type. The activation
of a hyperlink in the examination report 56 may involve positioning the
cursor 50 over the desired hyperlink and "clicking on" an appropriate
button on a mouse of the input device 16 of FIG. 1, or merely "hovering"
the cursor over the desired hyperlink. Similar to the "pressing" of the
button 44A in FIG. 3, the activation of the hyperlink 58A initiates the
display of the ultrasound image 52 which was used to compute the 8.1 cm
femur length. The ultrasound image 52 may be displayed on the display
device 18 as a solitary image, replacing the examination report 56, or as
a superimposed image over the examination report. The examination report
56 may also include a checkbox field 54 for each measurement value
included in the examination report.
A method of storing and managing measurement values of anatomical features
of a patient or a fetus, including the corresponding ultrasound images,
using the ultrasound imaging system 10 of FIG. 1, will be described with
reference to FIG. 6. At step 64, an ultrasound image of an anatomical
feature is captured by scanning the ultrasonic scanhead 12 on a patient or
a mother of the fetus on an area that coincides with the anatomical
feature of interest, such as a femur or a humerus. In a well known manner,
ultrasound waves are transmitted from the scanhead and then echoes of the
ultrasound waves that have been reflected from the anatomical feature are
received by the same scanhead. The echoes of the ultrasound waves are
converted into electrical signals and transmitted to the processor 30 of
the processing unit 14. The processor creates the ultrasound image of the
anatomical feature by processing the received electrical signals. Next, at
step 66, a dimensional aspect of the imaged anatomical feature is measured
to derive a measurement value of the anatomical feature. For example, the
length of the anatomical feature, e.g., a femur, may be measured during
this step. The procedure for measuring an anatomical feature depicted in
an ultrasound image is well known in the art.
At step 68, descriptive text is entered into the system for the measurement
value by typing the text on the input device of the system. The
descriptive text will appear with the measurement value in an examination
report that will be subsequently generated. In response to step 68, the
descriptive text is automatically incorporated into the ultrasound image
that corresponds to the measurement value by the report generator, as
indicated by step 70. This automatic step ensures that the ultrasound
image will be stored in an annotated form for verification, if the
ultrasound image is later saved. At step 72, the measurement value of the
anatomical feature is saved by the sonographer, if the sonographer decides
that it should saved. The sonographer may save the measurement value by
pressing a button on the scanhead 12 or pressing a key on the input device
16. At step 74, the corresponding ultrasound image is automatically saved
by the automatic ultrasound image saver 36 of the report generator 24.
This automatic step ensures that for each measurement value saved, the
corresponding ultrasound image is also saved. Steps 64 through 74 may be
repeated on the same anatomical feature to derive redundant measurement
information. Furthermore, steps 64 through 74 may be repeated on other
anatomical features of the patient or the fetus to gather different
dimensional measurements.
After all the measurement values of interest and the corresponding
ultrasound images have been saved, an examination report is generated by
the report generator 24 of the system 10, as indicated by step 76. The
examination report can be electronically displayed on the display device
18. The examination report contains the saved measurement values. In
addition, the examination report may include information that relates to
the patient or the mother of the fetus. The examination report may also
include an analysis derived from the saved measurement values by the data
analyzer of the report generator. As an example, the analysis may indicate
any abnormalities of the patient or the fetus. In the case of a fetal
examination, the analysis may include an estimated gestational age of the
fetus.
In one embodiment, the examination report contains a number of virtual
buttons. Each virtual button includes the measurement value and the
descriptive text that were entered prior to saving the measurement value.
The virtual buttons allow a viewer of the examination report to examine
the corresponding ultrasound image for each measurement value on the
examination report. When a virtual button of a particular measurement
value is activated, the examination report that is displayed on the
display device 18 of the system 10 is replaced with the ultrasound image
that corresponds to the particular measurement value. In an alternative
configuration, the corresponding ultrasound image is displayed in a
superimposed manner over the examination report when the virtual button is
activated, such that the corresponding ultrasound image and most of the
examination report are simultaneously visible on the display device. This
feature provides an efficient means to invalidate or verify any outlying
measurement values. In addition, this feature allows the viewer to
selectively examine only the ultrasound images that are of interest
without reviewing all the saved ultrasound images.
In another embodiment, the examination report contains a number of
hyperlinks. Each hyperlink is associated with a saved measurement value.
The hyperlink may be in a form of underlined descriptive text in which the
descriptive text is the text that was entered prior to saving the
measurement value. The hyperlinks operate in the same manner as the
virtual buttons. When a hyperlink of a particular measurement value is
activated, e.g., by "clicking on" or "hovering" a cursor over the
hyperlink, the examination report that is displayed on the display device
18 is replaced with the ultrasound image that corresponds to the
particular measurement value. In an alternative configuration, the
corresponding ultrasound image is displayed in a superimposed manner over
the examination report when the hyperlink is activated.
In either embodiment, each virtual button or hyperlink may also include a
checkbox field that can be checked or unchecked by the viewer of the
examination report. The ultrasound images that correspond to the
measurement values having a checked field can then be collectively
transmitted to a destination via the network 32. This feature allows the
viewer to eliminate an extra step of reviewing all the saved ultrasound
images prior to transmission. The review of the ultrasound images for
transmission can be accomplished during the examination review when the
measurement values and the corresponding ultrasound images are reviewed
for any errors.
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