Interactive Goal-Directed Ultrasound Measurement System

The present invention relates to ultrasound measurement systems and methods of making measurements from ultrasound images. Ultrasound measurement systems typically are used to make measurements from a displayed ultrasound image. The ultrasound image is provided from an ultrasound imaging system, a recording device, or an off-line storage system.

Ultrasound imaging systems can produce images of a patient's internal organs for display on a monitor. The information measurable from the monitor depends on the operational mode of the displayed image. For example, a two-dimensional mode (2-D), sometimes known as B-mode, allows for the measuring of distances, areas and volumes off of the display screen; a Doppler mode allows for the obtaining of measurements that indicate velocities from the display screen; a motion mode (M-Mode) shows the movement of structures in one-dimension over time.

One prior system for making ultrasound measurements is to use a ruler or hand-held calipers to make the desired measurements from a display screen. By knowing the scale of the screen view, the physical distance on the screen can be manually converted into a desired measurement. A relatively large margin of error is associated with the use of the hand-held calipers or rulers. Additionally, the manual computation of the results, either with a calculator or with pen and paper, introduces another potential error.

Other ultrasound measurement systems use computerized tools. These systems use graphical measurement tools that appears on the display screen and allow for the measurement of structures in images displayed on the display screen. Ultrasound measurement systems that use computerized tools include the Acuson 128XP Computed Sonography System, described in the "Acuson 128XP Computed Sonography System User Manual for Cardiovascular Applications", sections 9 and 10, copyright 1991 by ACUSON Corporation, incorporated herein by reference. In the Acuson 128XP Computed Sonography System, when a measurement is selected from a menu on a display screen, the pertinent computerized graphical tools are shown on the display screen. These graphical tools allow a desired measurement to be made off of the display screen. Measurements can be done in different operational modes and the measurement is interpreted accordingly.

The present invention is a goal-directed computerized ultrasound measurement system. The measurement menus of the ultrasound measurement system of the present invention that allow for the selection of measurements are arranged according to the reasons for which someone would use the ultrasound measurement system. The present invention does this by associating some of the measurement menus with potential conditions of the patient.

Typically, the operator of an ultrasound measurement system will use the system to help evaluate whether a patient has a certain condition. These potential conditions can be relatively broad categories such as valvular regurgitation or can be narrower categories such as mitral valve regurgitation. The potential condition may be identified before the examination begins or the user may identify a potential condition during the examination due to the ultrasound image or preliminary results.

The menu structure of the ultrasound measurement system of the present invention allows the user to select a menu branch associated with a potential condition. This menu branch can be a single measurement menu or can include submenu(s) and measurement menus linked to these submenu(s). The menu branch associated with a potential condition allows for the selection of a set of measurements suggested for that potential condition. A measurement menu in the menu branch can contain some or all of this set of suggested measurements. In a preferred embodiment, the set of suggested measurements contains less than all of the measurements that can be made by the system. The set of suggested measurements can be used to produce results that aid in the determination of whether the patient has the potential condition.

Prior ultrasound measurement systems do not associate a potential condition of the patient with measurement menus. Some prior ultrasound measurement systems request that the user input a diagnosis as background information along with the patient's name and I.D. number. The prior ultrasound measurement systems do not use this diagnosis information in arranging the menus of the ultrasound measurements or provide a set of suggested measurements for a potential condition. Prior systems force the user to review the list of all possible measurements in order that the user can select the desired measurements even if a diagnosis is input.

Prior ultrasound measurement methods are time consuming to perform, and require that the user have a comprehensive knowledge of what to measure for each potential condition. Many measurements not germane to the context of a given patient are customarily skipped by a knowledgeable user of the prior ultrasound measurement systems in the interest of efficiency. The menu structure of the ultrasound measurement system of the present invention is preferably arranged such that measurements non-essential to evaluating a potential condition are not shown to the user. Only the set of suggested measurements for a given condition are shown and selectable when the user has selected a potential condition. In this way, the user does not have to recall a comprehensive list of measurements appropriate to the condition.

Additionally, since in the prior methods many measurements were skipped by the ultrasound measurement users, a measurement which is required to produce a calculated value may be easily overlooked or forgotten during the measurement process. This could require the retesting of the patient; remeasurement from an archive medium which is less accurate than measurements made while connected to an ultrasound image measuring system; or even worse for accuracy, the gross estimation of a skipped measurement and the manual recalculation of the value. The ultrasound measurement system of the present invention will prompt the user to make the measurements required for the calculations relevant to the potential condition. The user need not know all the measurements required for complex calculations (e.g. LV Mass) to generate the end result. Prior systems used view or mode related menus which required knowledge of the measurements required for such complex calculations.

The ultrasound measurement system of the present invention can also arrange the results including calculations and relevant measurements in a manner appropriate for the potential condition for which the measurements were taken. This arrangement makes it easier for the user to evaluate the potential condition. In the prior systems, a good deal of non-germane data or textural placeholders and empty numerical data must be visually scanned and inspected to obtain the desired information.

The advantages of the Ultrasound Measurement System of the present invention can be illustrated with a few typical scenarios. Consider a post-surgical Coronary Artery Bypass patient with signs of left ventricular dysfunction for which an echocardiagram is ordered to access the function. The patient is in a crowded room with barely enough room for the patient and nursing staff when the ultrasound system is wheeled in with the sonographer. The patient is attached to a ventilator and five intervenous lines; a urinary catheter and other drainage tubes are in place. The patient has a chest incision with staples and bandages, and is restricted to a supine position (not the best position for obtaining images). A duplicate set of electrocardiogram (ECG) patches must be placed, because the nurses do not want the patient off the ECG monitor. There is very limited access to the patient for imaging.

Tension is high. The nursing staff wants access to the patient. They want the ultrasound people and system out of the room as soon as possible. The patient is having severe arrhythmias, and the nurses do not want the ECG monitors disconnected.

The ultrasound measurement system user needs to get in and out of the room as quickly as possible with all the pertinent clinical information to make a diagnosis and form a clinical strategy. During the evaluation, the ultrasound measurement system of the present invention provides the sonographer with a check-list of suggested measurements to assess the left ventricular function. Since the suggested measurements are provided to the user, the exam time can be reduced and a complete set of results ensured.

The menu provided for assessment of LV systolic function is shown below. Measurements associated with wall scoring analysis (not shown) may also be used.

LV Systolic Function

M-mode

LV Diameter in diastole and systole

MV EPSS

LVET

LVPWD

LV Major Axis, s

2D

PSAX

LV Minor Axis, chord in diastole and systole

LV Minor Axis, pap in diastole and systole

LV Area, pap in diastole and systole

A4C

LV Area in diastole and systole

LV Major Axis in diastole and systole

LV Minor Axis in diastole and systole

A2C

LV Area in diastole and systole

LV Major Axis in diastole and systole

LV Minor Axis in diastole and systole

Doppler

MR Slope

AoV Mean Accel.

AoV AT

AoV ET

Using the menu above, the specific measurements that are needed to assess the left ventricular function are obtained. Productivity and accuracy are increased. Repeat examinations are typically avoided, due to the check-list approach of the ultrasound measurement system of the present invention. All related result values are presented together in a clinically sensible arrangement, making the differential diagnostic process more straightforward for the physician interpreting the results. The goal-directed approach of the ultrasound measuring system is especially useful since a sonographer in the cardiac setting usually works independently and then presents the results to a cardiologist after the examination.

A second scenario concerns a newborn infant, shocky with poor perfusion. Murmur and diminished pulses are noted. The infant is to be evaluated for aortic stenosis.

The infant is in a crowded neonatal intensive care room with several isolettes of premature and newborn infants, all critically ill. Several nursing staff and physicians are in the room. There is limited work space in the isolette.

As in the first scenario, tension is high. The newborn infant is critically ill and there is a need to determine a diagnosis and course of clinical strategy.

Aortic stenosis is selected as a potential condition on the ultrasound measurement system. The ultrasound system now steps the operator through a goal oriented examination, systematically assessing the heart for aortic stenosis. The ultrasound measurement system prompts the operator to make the measurements that aid a doctor in the determination of the severity of the aortic stenosis, whether the aortic stenosis is valvular, subvalvular or supravalvular, and whether it is a critical aortic stenosis or not.

In critical aortic stenosis, the output is decreased, therefore, peak gradients from Doppler can be misleading (low values). The ultrasound measurement system of the present invention would prompt the user to make measurements in the Valvular Stenosis, Aortic Valve area. The suggested measurements for Valvular Stenosis, Aortic Valve area are a combination of M-mode, 2-D and Doppler measurements that provide for a rapid, non-invasive assessment in the diagnosis of the anatomic type and severity of aortic stenosis. As discussed in Snider, "Echocardiography in Pediatric Heart Disease", Year Book Medical Publishers, Inc., the gradients alone in this case would not reflect the actual severity of critical aortic stenosis. The measurements prompted by the ultrasound measurement system in a preferred embodiment are:

Valve Stenosis

Aortic Valve

M-Mode

IVS in diasrole and systole

LV in diastole and systole

LVPW in diastole and systole

2D

LV mass, Area Length

LV epi. Area, in diastole

LV endo. Area, in diastole

LV Major Axis, in diastole

LV mass, Truncated Ellipsoid

LV epi. Area, in diastole

LV en do. Area, in diastole

LV area, A4C, in diastole

LV Major Axis, in diastole

LV Semi-major Axis

LV TSM Axis

LV Minor Axis

Aortic Doppler

AoV Vmax

AoV Peak Grad.

AoV VTI

AoV Mean Grad.

AoV AT

AoV ET

AoV Continuity Equation

AoV Vmax

AoV VTI

AoV Mean Grad.

AoV Mean Accel.

AoV AT

AoV ET

LVOT Vmax

LVOT VTI

LVOT Vmean

LVOT Mean Grad.

LVOT Diameter

PISA AoV

AoV PISA Radius

AoV PISA Radius Vel.

AoV Vmax

AoV VTI

AoV Vmean

AoV Mean Grad.

AoV Mean Accel

AoV AT

AoV ET

AoV PISA

AoV Peak flow

The ultrasound measurement system of the present invention allows for the rapid, accurate assessment of whether the aortic stenosis is critical. If critical aortic stenosis is indicated, the physician needs to plan the appropriate clinical course of action, which usually includes the possibility of emergency surgery.

This second scenario illustrates the advantage of the ultrasound measurement system of the present invention for an infant with critical aortic stenosis. Had the sonographer or physician only measured the gradient, the values would be within the normal ranges. The gradient calculation alone would not give an accurate clinical picture, because the gradient calculation is dependent on the transvalvular flow, which in this case is severely diminished. Evaluating the left ventricular function, as prompted by the suggested measurements for aortic stenosis in the ultrasound system of the present invention, is essential to determine the critical nature of the aortic stenosis.

The ultrasound measurement system provides for a rapid, comprehensive assessment of the aortic valve and left ventricle in a critical aortic stenosis case, which may otherwise be incorrectly graded in severity.

The above and other features and aspects of a present invention will become more apparent upon reading the following detailed description in conjunction with the accompanying drawings, in which:

FIG. 1 is a diagram showing an ultrasound measurement menu structure of the present invention.

FIG. 2 is a simulated view of a display from a display screen showing the displayed menu choices.

FIG. 3 is a simulated view of a display on a display screen showing the menu after selection of several choices.

FIG. 4 is a diagram of the menu structure of a preferred embodiment of the present invention.

FIG. 5 is a diagram showing the measurements associated with valvular stenosis in the preferred embodiment of the present invention shown in FIG. 4.

FIG. 6 is a diagram showing the measurements associated with ventricular function in the preferred embodiment of the present invention shown in FIG. 4.

FIGS. 7A-D are diagrams showing the measurements associated with valvular regurgitation in the preferred embodiment of the present invention shown in FIG. 4.

FIGS. 8A-B are diagrams showing the "basic" measurements in the preferred embodiment of the present invention shown in FIG. 4.

FIG. 9 is a diagram of an apparatus of the present invention showing an ultrasound measurement system along with an ultrasound device.

FIG. 10 is a diagram of the software architecture used with a preferred embodiment of the present invention.

display screen- device used to present information to the user; the display screen can include but is not limited to monitors, printers, liquid crystal displays, and light emitting diode displays.

input device- input devices include but are not limited to keyboards, mouses, trackballs, soft keys, voice activation systems and touch screen systems.

menu branch- a single menu or linked group of menus

potential condition- a possible condition, malady or problem of a patient which is to be examined or evaluated. Potential conditions include conditions that the operator desires to rule out. Anatomical regions by themselves should not be considered potential conditions. Thus "heart" or "heart problem" are not potential conditions, while "valvular stenosis" or "mitral valve regurgitation" are potential conditions.

ultrasound measurement- includes measurements made from an ultrasound image; the selection of an ultrasound measurement can include the prompting of the system to prepare to make this ultrasound measurement.

ultrasound measurement system- apparatus for making measurements from an ultrasound data or image. The ultrasound image can be provided from an ultrasound imaging system, a recording device, or an off-line storage system that is not considered part of the ultrasound measurement system.

FIG. 1 is a diagram illustrating the menu structure of the present invention. The ultrasound measurement system of the present invention is in the preferred embodiment focused on cardiac calculations. Other areas for which the ultrasound measurement system may be useful include obstetrics, vascular, and general abdominal imaging applications.

When cardiac calculations is selected, menu 20 lists selectable logical categories. These logical categories in main menu 20 can include a basic category 20a, potential conditions such as Potential Condition I and Potential Condition II, as well as other categories that are not necessarily potential conditions. Associated with each of the groupings in the main menu 20 is a menu branch that contains ultrasound measurements selections that are selectable by the user. Menu branch 22 associated with Potential Condition I is shown in FIG. 1. Menu branches can include a single menu or a group of menus.

The menu structure of the present invention is different from the prior art because menu branches can be associated with a potential condition. Suggested measurements for the potential condition including measurements 32, 34 and 36 can be selected in the branch 22 associated with Potential Condition I. The measurements associated with a potential condition, such as Potential Condition I in the menu branch 22, are preferably not all of the measurements that can be selected using the system. Even the measurements of the menu branch associated with the basic group may contain less than all of the measurements. The basic measurements can be the measurements which would be suggested for a general examination of an anatomical region, such as the heart.

In the menu structure shown in FIG. 1, a category from list 20 is selected. If Potential Condition I is selected, menu 24 will appear. A heading is then selected from menu 24. If heading I is selected, then menu 26 listing subheadings will appear. If subheading I is selected list 28 of the measurements will be shown.

The measurement menu structure shown in FIG. 1 allows the user to logically step through the suggested measurements for a potential condition. The heading and subheading are logical groupings that can include sub-regions, ultrasound operation mode, or a specific calculation. Menu 24 and 26 are sub-menus that provide links to other menus. Menus can include both links to other menus and measurements.

Note that the headings and sub-headings may further define another potential condition. For example if Potential condition I is "valve regurgitation" then heading I may be "mitral valve" so that another potential condition "mitral valve regurgitation" is associated with the menu branch 23. Menu branch 23 is also a part of menu branch 22. The set of suggested measurements in menu branch 23 is sub-set of the measurements selectable from menu branch 22.

FIG. 2 is a simulated view of a display screen showing displayed main menu choices. Using a keyboard, trackball or mouse, the desired logical category can be selected. In FIG. 2, the selection for pressure predictions is marked and can be selected. The logical category shown in the menu of FIG. 2 include potential conditions such as valve stenosis and valve regurgitation.

FIG. 3 is a simulated view of a display screen showing the menu display after several menu selections. In this case, the category for the potential condition, "valve stenosis" is selected. Additionally, the heading for the region aortic valve (AoV) and the subheading for the continuity equation are selected. At this point, measurements such as AoV TRACE and LVOT TRACE can be selected. LVOT DIAM is shown in gray, since the ultrasound operational mode needs to be switched before selecting this measurement. The user can return to any other menu in the menu structure by selecting the heading or category shown in the menu of FIG. 3. The user can go through all of the measurements associated with a potential condition such as the "valve stenosis" or "aortic valve stenosis" in order to produce the results that are necessary to evaluate the potential condition.

As done in prior ultrasound measurement systems, when a measurement, such as the AoV TRACE, is selected, the appropriate computerized measurement tools will appear on the display screen. The computerized measurement tools can be used to make the desired measurements, these measurements are stored for display and for calculation of results.

FIGS. 4-8 show the menu structures and measurements for a preferred embodiment of the present invention which is used to produce cardiac calculations. FIG. 4 is a diagram of a menu structure for a preferred embodiment of the present invention. Menu 50 shows the list of the categories of the cardiac calculations. These categories include the basic measurements, Doppler pressure predictions, valvular stenosis, valvular regurgitation, shunts, ventricular function and wall scoring. Valvular stenosis is the narrowing of a valvular orifice that obstructs outflow. Valvular regurgitation is a retrograde flow of blood through a heart valve. A shunt is a congenital defect that allows for flow between structures or chambers including e.g. interatrial septal, ventricular septal, atrioventricular septal, patent ductus, and coronary sinus fistula. Also shown in FIG. 4 are the listings for the Doppler pressure predictions 52, valvular stenosis 54, valvular regurgitation 56, shunts 58 and ventricular function 60. The abbreviations used in FIGS. 4-8 are expanded in Appendix I.

FIGS. 5-8 show the measurements associated with the logical groupings. FIG. 5 lists the measurements associated with valvular stenosis. The measurements associated with the valvular stenosis are broken down into aortic valve measurements 62, pulmonary valve measurements 64, mitral valve measurements 66, tricuspid valve measurements 68 and generic proximal isovelocity surface area (PISA) measurements 70.

FIG. 6 is a diagram showing the measurements associated with the ventricular function category. The measurement lists include LV systolic function 72, RV systolic function 74, LV diastolic function 76, RV diastolic function 78.

FIGS. 7a and 7b list the measurements associated with valvular regurgitation. The lists include aortic valve measurements 80a, 80b and 80c; mitral valve measurements 81a and 81b; tricuspid valve measurements 82; pulmonary valve measurements 84a and 84b; generic PISA measurements 86.

FIGS. 8a-8b disclose the measurements associated with the "basic" measurement logical grouping. List 88 shows header and sub-header selections. The "Basic" measurements include "M-mode" or motion mode measurements 90, 2D chamber dimensions measurements 92, 2D chamber dimensions parasternal long axis (PLAX) 94, 2D chamber dimensions parasternal short axis (PSAX) 96, 2D chamber dimensions Apical 98, 2D chamber dimensions suprasternal notch (SSN) 100, 2D volumes 102, 2D mass measurements 104, basic Doppler measurements 106.

The user of the ultrasound measuring system of the present invention can customize the lists of measurements by disabling specific tests. The prior 128XP Acuson product also has this ability. Disabled measurements are not displayed to the user for selection.

The calculations involving the measured values can be done automatically in the background as the measurements required in a given calculation are completed. The calculated values are then stored for later display. The calculations used in the system are typically functions of the measurements made in the system. Additional required variables can be input by the user. A list of calculations used in the preferred embodiment of the present invention is shown in Appendix II. Additional calculations can be added as suggested by users. These calculations are obtained from publicly available articles and textbooks. Examples of many of these equations are given in section 10 of the "Acuson 128XP Computed Sonography System User Manual for Cardiovascular Applications". The suggested measurements for a potential condition are chosen such that the desired results for evaluating the potential condition can be displayed after the suggested measurements are made. The results can be arranged for display according to the potential condition being evaluated. This allows for the logical display of results to the user. Non-pertinent results can either be not displayed or displayed less prominently.

FIG. 9 is a diagram of an ultrasound measurement system 122 connected to the ultrasound imaging system 124. The ultrasound imaging system 124 is responsible for the acquisition and presentation of the actual ultrasound image from which the measurements are taken. The image is placed on display 128 of display screen 126. This image may be, for example, a two-dimensional image 128a of a valve. The display screen 128 is preferably a high quality monitor, such as that available from the Barco company. The ultrasound imaging system 124 can be controlled by the same computer 130 used for the ultrasound measurement system or alternately a second computer (not shown) can be used to interface with the ultrasound measurement system processor or computer. In a preferred embodiment, the ultrasound imaging system control software and the measurement systems calculation software are placed on the same computer 130 so that the programs can easily interface with one another. Preferably the system control software processes include an operating system, such as the UNIX operating system, and a graphics system, such as the X-windows graphics server. The graphic system is loaded into the processor 130a of the computer 130 and controls the display 128 on the display screen 126. Processor 130a should be powerful enough when it is configured with the operating system, graphics system, and other hardware, to provide a sufficiently responsive user interface. "Responsiveness" is somewhat subjective but most developers are familiar with sources of guidelines, such as the Human Factors Society and the Association for Computing Machinery Special Interest Group on Computer Human Interaction (ACM SIGCHI). Processor 130a is in a preferred embodiment a 486 microprocessor.

The measurement systems calculation software (CalcApplication) is stored in memory 130b of the computer 130. In a preferred embodiment the memory 130b includes a hard disk on which the configuration information which determines the specific contents and organization of a particular calculation package is stored. The hard disk can also be used as a general resource by other subsystems. The CalcApplication software module acts as an interface between the calculation system and an ultrasound imaging device. The CalcApplication software module includes subcomponents which are detailed in FIG. 10. The CalcApplication software module coordinates the actions of the software subcomponents and the other components of the calculation system to affect the behavior of the calculation system.

In a preferred embodiment, the input devices 132 for the ultrasound measurement system include the track-ball and select key 134 and the console keys 136. Other possible input devices include voice recognition systems, touch screen systems and any other way to control the menu 128a displayed on the display screen 126. The track ball 134 provides a means for manipulating the graphical tools. Typically, the user make selections from the menu region 128b displayed on the display 128 until a measurement is selected. When a measurement is selected the appropriate graphical representation tool such as the ellipse 128c appears on the display screen 126. The track ball 134 can be used for matching the elliptical graphical tool 128c with the area of valve 128a displayed on the display screen 126. Using the select keys and the track ball, the center and different axes of the elliptical measuring device can be maneuvered. Once the elliptical device 128c matches the area of the valve 128a, the user can press a button to capture this measurement and the area defined by the elliptical tool 128c is automatically stored and is available for making calculations. Alternately, the user can use the trace function to trace the actual area of the chamber or valve. Examples and descriptions of graphical tools that can be used with the present invention are discussed in section 9 of the "Acuson 128XP Computed Sonography System User Manual for Cardiovascular Applications".

In addition to an ultrasound imaging system 124, an off-line recording or VCR recording of the ultrasound data could be used. In this way, the measurements can be made after the patient has already been examined. The disadvantage of this method is that the measurements may be somewhat less accurate, due to degradation of the image quality on the second generation image source.

FIG. 10 shows the architecture of the CalcApplication and its sub-components. The format of this figure is in the spirit of a Booch class diagram which is a known way of representing objected-oriented systems. The preferred embodiment is written primarily in C.sup.++, which allows some opportunity for code re-use through class hierarchies. Key base classes are noted, but the complete inheritance hierarchy is not given.

The CalcApplication class 140 is intended to have only one instance. It contains the other major subsystems of the calculation system, coordinates their behavior, and provides their primary interface to the remainder of the ultrasound machine.

The Measure Menu Structure 142 class is also intended to have one instance. It is the software module which maintains the complete menu structure for the Calculation Package and provides access to the Menu Tool 144 through which the user chooses a measurement to perform. The Measure Menu Structure reads the description of the menu structure from a data file on the ultrasound system's hard disk when the System is initialized. The Measure Menu Structure is also responsible for maintaining the user's current location in the Measure Menu Structure between presentations of the Menu.

The Menu Tool 144 is a separate component of software which is responsible for issuing commands to the ultrasound machine's X-Windows server to effect the actual graphical presentation of the menu. Such software components are commonly written by the developers of graphical user interfaces. In the preferred embodiment, the Menu Tool is implemented using the concepts of Motif widgets which have been extended to display the user's previous choices in the menu hierarchy. The user manipulates the menu tool with the ultrasound machine's Trackball and Select Key, whose output is routed to the CalcApplication, then to the Measure Menu Structure, and finally to the Menu Tool.

The CalcTalk Parser 146 class is intended to have one instance. It is the software module which parses Calculation System data files in the CalcTalk language, the current definition of which is given in appendix III. The CalcTalk parser is implemented using lex and yacc, software tools well known to programmers who work in the UNIX environment.

The CalcTalk files, which in the preferred embodiment are stored on the ultrasound machine's hard disk, contain descriptions of 1) the clinical data, called "Results" in this architecture, measured and manipulated by the Calculation System, 2) the procedures, called "Measurements" by which the user measures quantities in the image data, 3) the calculation formulae by which higher order data are derived from measured quantities, and 4) the report definitions by which measured quantities and higher order data are presented in an organized fashion on a full-screen form or printed output. These CalcTalk files describe the contents of the Calculation package; they are read and parsed when the system is initialized. The CalcTalk Parser transmits the definitions of Results, Measurements, Calculations, and Reports to the Result Repository 148, Measurement Dictionary 150, Calculation Dictionary 152, and Report Manager 154, respectively.

The Result Repository 148 class is intended to have one instance, which acts as the database of measured and derived quantities for the Calculation System. The Repository contains the structure of the possible quantification data which the Calculation Package can contain, and it also contains the specific instances of data pertaining to the current exam. Appendix III describes in greater detail the Calculation System's capabilities for organizing and manipulating quantification data; in this preferred embodiment these capabilities are implemented in the Result Repository. There is one instance of the Result 156 class for each piece of quantification data in the Result Repository. Results can be both produced (i.e., have their values set by the output of) and consumed (i.e., have their values serve as input to) by Measurement Tools 158, Calculations 160, and Report Panels 162. Results and their Producers and Consumers can be dynamically configured in a dependency network such that changes to input Results propagate through the network. The data types of Results available, the operators on those data types, and the details of binding Results to the output ports of Producers and the input ports of Consumers are described more fully in the appendix III. The preferred embodiment includes base classes for Result Producers and Result Consumers.

The Bulletin Board 164 class maintains that part of the state of the Calculation System which is not quantification data. It is an entity onto which other components can post an item or a piece of information so that it can be seen or used by other components. System components can also remove posted items. In the original architecture, the posted items are of, or are derived from, class Note 166. For performance reasons, the system is implemented without a Note base class and items are posted directly to the Bulletin Board. There are two Bulletin Board instances in the preferred embodiment: one which maintains the local name space during the execution of a procedure by the Measurement Engine, and the Main Board which maintains posted items across procedures. Posting items as described in the appendix III places them on the Main Board. The CalcApplication posts and removes items from the Main Board to indicate the state of the ultrasound machine.

The Predicate class 168 is intended to have multiple instances. It provides the ability to evaluate a Boolean expression based on the existence of Results 156 in the Result Repository 148 and Notes 166 on the main Bulletin Board 164. Predicates also provide the capability to assign local names to the objects for whose existence they test, items as described in the appendix III.

Predicates contain instances of the Note reference 168 class and the Result Reference 170 class. The former performs a query of the main bulletin board about the existence of a postable note and the latter performs a query of the Result Repository about the existence of a particular Result (or, as described in the in appendix III, a series of Results).

Predicates supply the general mechanism by which Measurements, Measurement Procedures, Calculations, and Reports are sensitive to the state of the Calculation System and the state of the ultrasound machine. Appendix III provides a full description of the CalcTalk syntax for Predicates and a description of each instance of Predicate usage.

The Measurement Dictionary 150 class is intended to have one instance. It is the software module that maintains the definitions of the Measurements by which the user measures quantities in the Image data; these definitions are entered by the CalcTalk Parser 146 during initialization. The Measurement Dictionary provides access to and the status of individual Measurements to the Measure Menu Structure 142 and Measurement Engine 172.

The definition of each entry in the Measurement Dictionary is represented as an instance of the Measurement Entry 174 class. This class has three Predicates: Enable, Select, and Satisfied, which test whether the Measurement may be presented to the user, whether the Measurement has been selected by the user, and whether the outputs of the Measurement already exist, respectively. The details of each Predicate are described in appendix III. The Enable and Select Predicates must evaluate to True for the Measurement to be presented in the menu. If the Satisfied Predicate evaluates to True, the Measurement will still be presented, but the presentation may include an indication that performing the Measurement is not necessary. In the preferred embodiment, this indication is presented as a check mark next to the Measurement name in the menu.

Each instance of a Measurement Entry includes one or more instances of the Measurement Procedure 176 class. Each such instance defines the sequence of steps executed by the Measurement Engine 172 to guide the user through the quantification of some image structure or structures. Each Measurement Procedure includes a Requires Predicate (described fully in the appendix III). If at least one Measurement Procedure for a given Measurement Entry has a Requires Predicate that evaluates to True, the user will be able to select that Measurement when it is presented in the Menu Tool. If none of a given Measurement Entry's Measurement Procedures have Requires Predicates which evaluate to True, the user will not be able to select the corresponding Measurement when it is presented in the Menu Tool. In the preferred embodiment, the Measurements which are not selectable are presented with a grayed out effect, familiar to the developers of graphical user interfaces, to so indicate.

The Measurement Engine 172 class is intended to have one instance. It is the software module that sequences the System through the steps of the procedure by which the user measures some quantity in the image data. The Measurement Engine communicates with the other components of the System and, through the CalcApplication 140, with the ultrasound machine. The Measurement engine is an interpreter optimized to execute the dynamic portions of CalcTalk. Its most frequently used commands include: directing the Tool Manager 178 to create specific tools, directing the Result Repository to create specific Results 156 and attaching the appropriate Results to the appropriate binding sites on the appropriate tools. The details of the Measurement Engine's capabilities are given in the appendix III.

The Tool Manager 178 class is intended to have one instance. It is the software module that manages the creation, use, appearance, and deletion of instances of the Measurement Tools 158 class, which are software modules that effect graphical tools by which the user can measure quantities in the Image data. Typical measurement tools are calipers, ellipses and traces, which are familiar to most users of medical ultrasound imaging equipment. The measurement tools are manipulated by the ultrasound machine's track ball, select key, and soft keys whose output is routed to the CalcApplication, then to the Tool Manager and then to the Tool being manipulated. In the preferred embodiment, the Measurement Tools use software libraries which issue commands to the X-Windows server to execute the necessary graphics commands.

The Calculation Dictionary 152 class is intended to have one instance, which manages the definitions and creation of the actual Calculations 160 in the Calculation System. Calculations are not manipulated by users directly, but instead automatically derive certain quantities from those measured directly. The structure of Calculations is very similar to that of Measurements, and is described fully in the appendix III.

The Report Manager 154 class is intended to have one instance, which manages the sections, instances of the Report Panel 162 class, of the on-screen forms in which the measured and derived quantification data are presented. Each Report Panel will be defined with four Predicates: Enable, Select, Requires, and Uses. The Enable, Select, and Requires Predicates should function similarly to those for Measurements and Calculations. The Uses Predicate will be somewhat different in that it will continue to retrieve Results after it has initially evaluated to True. These Predicates will provide the mechanism by which the Report presents data relevant to the assessment goals indicated by the user through menu selections.

The Report Panel 162 will provides the mechanism for displaying one atomic section, or panel, of the on-screen Calculation System report form. In the preferred embodiment, this class will use Motif and custom widgets, software tools well known to developers of graphical user interfaces.

Various details of the implementation and method are merely illustrative of the invention. It will be understood that the various changes and such details may be within the scope of the invention, which is to be limited only by the appended claims. ##SPC1##