The present invention relates to a system for assisting a physician to arrive at a patient diagnosis, to determine the optimal sequence of clinical actions from diagnosis to therapy, and to provide hints on alternative diagnostic or therapeutic measures.
The current procedure for a physician to use existing knowledge to determine the correct diagnosis for a patient is usually driven by personal experience, guidelines and best practices. A diagnosis frequently has a hierarchical structure, such as breast cancer, ductal carcinoma in situ, HER2 positive and ER negative. The final diagnosis for the patient's disease state is carried out in a sequence of measurements and assessments. The measurements include simple tasks, such as measuring the patient's weight and asking for her smoking habits. The measurements may also, however, be very sophisticated, such as measuring the lymph node size in computed tomography (CT) images or evaluating the HercepTest score in HER2 immunohistochemically stained tissue microscopy images. Each measurement and its assessment may be summarized as a clinical action.
The sequence of clinical actions and the decision on how to proceed may be considered as following a path in a semantic network. Each action may be considered as an edge of the network, and each decision on how to proceed and each characterization of the patient's health state can be represented as a node of the semantic network. The diagnostic procedures may be structured hierarchically with the top categories being radiology, pathology, the case history and the physical examination. On the lower level in the radiology category are X-ray and magnetic resonance tomography (MRT) results. In the pathology category are tissue examination by H&E staining and immunohistochemistry (IHC).
Therefore, finding the best sequence of clinical actions to determine the most appropriate diagnosis is equivalent to an optimization problem on how to find the shortest path in a semantic network. The starting semantic network node for the path is the current patient disease state, and the ending semantic network node is the state of the patient after treatment. Thus, the treatment options determine the sequence of steps in the diagnosis. Without available treatment options, there is no need for a diagnosis.
A method is sought for navigating from the starting semantic network node to the ending semantic network node in an optimal way.
A clinical decision support (CDS) system determines the probable outcome of applying clinical actions to a current patient by performing a similarity search that compares the health record of the current patient to the electronic health records of other patients stored in a clinical database. The CDS system includes a software application that executes on a processor of a computer. The software application analyzes the stored electronic health records of a large number of patients in order to determine those patients whose health history is most similar to that of the current patient. The software application then uses knowledge about the clinical paths followed in the past by the most similar patients and recommends potential diagnostic and therapeutic steps for the current patient.
In a first embodiment, the CDS system receives an electronic health record of the current patient that indicates a past clinical action applied to the current patient. The system performs a similarity search in a database of health records of patients in order to identify a group of patients who are similar to the current patient. The similarity search determines the similarity between two patients based on their electronic health records. Based on the electronic health records of each patient in the group of similar patients, the system calculates a corresponding quality value applicable to the current patient. Each quality value indicates the probability that a sequence of clinical actions that were applied to the corresponding similar patient will be successful if applied to the current patient. The system then indicates the clinical actions that are associated with the highest quality value. The clinical actions are indicated by displaying a representation of those clinical actions on a graphical user interface of the CDS system.
Each quality value for the current patient that corresponds to those clinical actions applied to a similar patient is determined based on estimated parameters for the current patient. For example, a quality value for the current patient can be determined based on a quality-of-life parameter for the current patient, an estimated disease free survival time for the current patient, an estimated overall survival time for the current patient or the cost of the clinical actions corresponding to the quality value.
In a second embodiment, the system receives the electronic health record of a current patient, determines that a first clinical action was already applied on the current patient, generates classifiers associated with potential future clinical actions, generates a success value for each electronic health record of another patient using the classifiers, displays the electronic health record of the other patient having the greatest success value, and indicates a proposed clinical action that is to be applied on the current patient. The system retrieves the proposed clinical action from a database in which patient medical records and associated clinical actions are stored.
In one example, the first clinical action was the acquisition of an x-ray mammography image, and the proposed clinical action is to acquire a magnetic resonance (MR) tomography image. Other examples of the proposed clinical action are: (i) a diagnosis that refines an earlier diagnosis obtained using the first clinical action, (ii) a therapy that follows a diagnosis obtained using the first clinical action, and (iii) an examination that extends the electronic health record of the current patient. At least one of the classifiers generates a success value using a fuzzy membership function to classify the stored electronic health record of another patients. The fuzzy membership function relates to an entry in the hierarchically structured electronic health record.
A representation of the proposed clinical action is then displayed on a graphical user interface of the system. The system also calculates a quality value indicating the probability that a sequence of clinical actions that were applied to a similar patient will be successful if applied to the current patient.
In a third embodiment, the system receives an electronic health record of a current patient that indicates a past clinical action applied to the current patient. The system identifies potential next clinical actions to be applied to the current patient and receives a decision as to which of the potential next clinical actions are to be applied to the current patient. The system determines a quality value for each of the potential next clinical actions that indicates the probability that each potential next clinical action will be successful if applied to the current patient. The system then determines which of the potential next clinical actions has the highest quality value and highlights on a graphical user interface a representation of the potential next clinical action having the highest quality value. The system generates a protocol that indicates the potential next clinical actions and the decision of which potential next clinical action to apply. The protocol is then displayed on a graphical user interface of the system.
In a fourth embodiment, an electronic health record of a patient is received that indicates a clinical action being applied to a current patient. A potential next clinical action to be applied to the current patient is identified. A success value for the potential next clinical action is determined that indicates the probability that the potential next clinical action will be successful if applied to the current patient. A quality value associated with a set of potential next clinical actions is determined. The quality value is based on the success value of each of the potential next clinical actions, as well as other parameters. The set of potential next clinical actions includes the potential next clinical action. The system determines that the set of potential next clinical actions has the highest quality value as compared to other sets of potential next clinical actions. The system then displays medical data on a graphical user interface supporting the determination that the set of potential next clinical actions has the highest quality value. The quality value is also calculated based on parameters such as the quality-of-life of the current patient undergoing each potential next clinical action, the estimated disease free survival time or overall survival time if the patient undergoes each potential next clinical action, and the cost of each potential next clinical action.
Other embodiments and advantages are described in the detailed description below. This summary does not purport to define the invention. The invention is defined by the claims.
The accompanying drawings, where like numerals indicate like components, illustrate embodiments of the invention.
Reference will now be made in detail to some embodiments of the invention, examples of which are illustrated in the accompanying drawings.
A novel Clinical Decision Support (CDS) system supports a physician in arriving at a patient diagnosis. The CDS system assists the physician to figure out the optimal sequence of clinical actions from diagnosis to therapy and provides hints on alternative diagnostic and therapeutic measures. The CDS system provides help without domineering over the physician.
The novel CDS system solves the problem of how to navigate the network of clinical actions and decisions in an optimal way. The optimal path through the decision tree is determined by the patient and her preferences and by the availability and cost of clinical services. Each clinical path starts with the current patient state, which is documented in her medical health records (MHR). The path ends with the patient in her preferred state, either perfectly healthy or, if that is not achievable, with optimal quality of live or maximum life expectancy. The parameters of the clinical path optimization are comprehensive and include, for example, the patient's or the patient's health insurer's willingness to contribute to health care costs, the availability and cost of diagnostic services (e.g., PET/CT), the probability that a given diagnostic step will increase the confidence in the diagnosis, and the availability of other clinical resources (e.g., beds, doctors).
To achieve the goal of finding the optimal path for a given patient, all relevant clinical actions must be associated with a cost. In particular, a value for the clinical actions that lead to the endpoint node must be determined. By introducing a common “currency,” an optimization method is used that determines the route with the lowest overall cost when following the actions and decisions from the start point to the endpoint. Although from an ethical perspective it might be difficult to value an incremental increase in life expectancy, a pragmatic approach is to follow consensus valuations from empirical studies with an average value of 50,000 per year of life (European Commission, CAFE 2003). By optimizing the path, the system automatically determines the optimal balance between the high cost of sophisticated diagnoses and advanced therapies with the benefits of longer life and higher quality of life.
One possible choice of an algorithm used to solve the shortest path problem is the Dijkstra algorithm. When using the Dijkstra algorithm to determine the shortest path through the semantic network, one should assume that each edge of the network is associated with a positive cost to find a path with the lowest overall cost. The CDS system uses the algorithm by associating clinical actions, such as diagnostic steps and therapies, with costs. The cost of reduced life time or quality of life is modeled using the edges leading to the endpoint node. It is important to note that in the assignment of costs to each clinical action, the costs must be risk-adjusted real costs. For example, an additional diagnosis based on magnetic resonance may have additional real costs, but due to its diagnostic power the subsequent clinical actions carry less risk, which in turn reduces the real costs.
Using Knowledge from Clinical Practice
For the patient currently being analyzed, the CDS system knows the path taken to arrive at the patient's current state. Using the patient's information, the CDS system 20 searches the clinical database 22 for patients with similar circumstances by comparing the path of the current patient with portions of the paths other patients. To determine the similarity between the path of the current patient and paths of other patients, the system 20 uses the similarity of the transited patient states (the nodes in the semantic network), the similarity of the clinical actions taken (edges in the semantic network), the similarity of the outcomes of the actions taken, and the similarity of the structures of the paths as a whole.
For example, to evaluate the similarity of the clinical action “perform a physical examination ‘edge’,” the system 20 computes the weighted Euclidean distance based on age and weight. The evaluation of a mammography image “edge” includes the computation of the similarities in the detected calcifications and masses based on the distribution patterns, densities, shapes and textures in the digital image. To obtain probabilities used in choosing clinical actions for the current patient, all similar paths from the clinical database 22 are aggregated using the similarity values as weighting factors. Using the aggregated path as an input to the algorithm for finding the optimal path provides the physician with a suggestion for the next diagnostic and therapeutic steps. Included in this suggestion is the on-demand access to the networks from which the suggestion was derived.
The value of the clinical database 22 increases with the number of patient histories it contains. Each patient history (if recorded correctly) contributes to the available network of actions and decision points. The success or failure of each diagnosis and therapy in the past enables the system 20 to repeat (or prevent) such routes. Therefore, the CDS system 20 supports a global clinical database 22 that aggregates knowledge far beyond the depth of an individual physician. To implement such a global clinical database using the constraints of privacy and ethics, all patient data contained therein should be anonymized so that each patient's identity can be retrieved only from the clinic that provided the data. For all other participating clinics, the patient's identity remains hidden.
Example 1 of Graphical User Interface of CDS System
The CDS system 20 provides a graphical user interface (GUI) for the interaction with a physician. The GUI displays patient information from the electronic health record (extracted from the hospital information system, HIS). A “findings” view of the GUI displays the patient's radiological and pathological images and other patient data (extracted from the Picture Archiving and Communication System, PACS), as well as recommendations on which clinical action should next be performed, such as additional diagnostic or therapeutics steps.
The GUI of
The time line panel 31 provides information on all clinical actions performed with the current patient in chronological order. Clicking on a past point in time displays the graphical user interface as it was at the prior point in time. Displaying the past point in time allows the physician to navigate easily to previous diagnostic steps and the associated clinical data for a quick review or recap.
Two kinds of information are displayed in the therapy options panel 34 that help the physician to proceed with the patient's health care plan. First, the suggested therapy options are displayed. The therapy options correspond to the diagnosis that is selected in the differential diagnosis panel 32. Each therapy option is listed along with a success value 29 indicating the probability that the therapy option will be successful. Second, the therapy options panel 34 also includes a recommended diagnostics section in which additional clinical actions are recommended in order further to refine the current diagnosis.
The data that drives the current clinical decision is displayed in the selected findings panel 33. This data includes information such as an x-ray mammography image, a pathology report, or a blood test result. Clicking on the magnifier symbol 35 allows the user of system 20 to navigate into the selected diagnosis in order to retrieve the underlying details. For example, when the magnifier symbol 35 of the sample GUI of
Clicking on the “MedBase” button 37 at the upper right of the screenshot of
In a manner similar to the display of
As soon as the diagnosis is sufficiently specific to start therapy, the differential diagnosis panel 32 becomes the primary therapy options panel 41, as shown in
Example 2 of Graphical User Interface of CDS System
The CDSS software application 21 uses a diagnosis-related classifier to assign a confidence value to each diagnosis. For example, confidence value that the BI-RADS 5 diagnosis is correct is 70% (0.7), as displayed in the “Findings & Diagnosis” section of the left side panel 43. The diagnosis-related classifier is calculated using membership functions of attributes extracted from the image analysis, as well as classifier values of subordinate classifiers.
The right side panel 44 shows treatment options retrieved using a similarity search of the clinical database “MedBase” 22. The suggested clinical actions are displayed towards the upper left of the right side panel 44. A success value appears in parentheses next to each treatment or therapy indicating the probability that the clinical action will be successful if applied to the current patient. For example, the “(0.05)” next to “Radiation therapy” indicates that there is a 5% probability that radiation therapy will cure the patient's breast cancer. The right side panel 44 a includes a list of recommended potential examinations that would refine the current diagnosis.
Example 3 of Graphical User Interface of CDS System
In the GUI of
At the top of a center panel 50 of the GUI is a set of icons that provides access to the results of different tests. Clicking on the icons reveals the results of the patient's blood tests and mammography as well as tissue-based data from pathology and gene expression data. The right-most icon of center panel 50 enables the physician to search for similar patients in the clinical database “MedBase” 22 in order to retrieve similar diagnoses, clinical actions and treatment successes. Below the icons is a set of conclusions. These conclusions are computed from the patient's clinical data and from the evaluation of the similarity search in MedBase. A conclusion is either a patient diagnosis, such as breast cancer, or the categorization of a finding in a medical image. Examples of categorizations of findings in medical images include a BI-RADS category for mammography images or an Elston-Ellis grading of H&E stained breast cancer tissue sections.
A right side panel 51 of the GUI shows information about recommended next diagnostic steps. For example, a diagnostic step could be to perform an oral “examination” in which the physician finds out more details about the patient's history. In a second embodiment of
The Clinical Decision Support System 20 has a layered architecture of data and software as shown in
The patient database 23 stores data on patients currently being treated. For each patient, the database 23 includes references to the underlying data sources (e.g. PACS, HIS), information about clinical decision points and clinical actions, and the associated healthcare costs. The clinical database 22 stores data on patients whose clinical outcome and treatment success is known. Here as well, for each patient in the clinical database 22 there is a reference to the underlying data sources (e.g. PACS, HIS), information about clinical decision points and clinical actions, the actual clinical outcomes such as disease free and overall survival times, and the total health care costs actually incurred. The CDS application 21 performs various services on the data in database 22 and database 23, such as image analysis, data mining, text mining, and a combination of these functions.
The CDS system 20 includes multiple user interfaces that allow different types of users to make decisions based on the output of the system. The user interfaces provide access to data and suggestions on which clinical actions to take. For example, a user may be an employee of a pharmaceutical company that is developing and evaluating diagnostics and drugs in a pre-clinical phase. Users may also be physicians treating patients in clinics, pathologists scoring patient biopsies and resections, radiologists examining x-ray, CT, PET/CT, MRI or ultrasound images, or patients themselves seeking advice as to their best treatment.
The CDS system 20 uses classifiers to perform the analysis tasks of the system. Each classifier has several inputs that use features. A feature is a measurement result or a calculation based on another feature. A classifier creates one output value from multiple complex inputs. For example, the output value of the system is a success value or a confidence level relating to a clinical action or a sequence of clinical actions (treatments and therapies). The structure of a classifier can remain the same regardless of the specific task of the classifier.
Addressing all tasks with the same type of classifiers has the advantage that complexity is reduced. Specialization of the experts who train the classifiers or fill them manually with content is not required. The experts can more easily learn the one model and the principles that apply to all of the classifiers. While the structure of all classifiers is always alike, the contents differ, i.e. the semantic meaning and the parameters. Using a generic classifier also reduces the complexity of data mining, as only one type of algorithm must be trained. Even for very different data mining tasks, only one training and optimizing mechanism is used. A fuzzy logic classifier is well suited to represent such a generic classifier concept.
Classifiers also perform image analysis as part of the process of generating success values or confidence levels. The lowest semantic level of the data network generated by the CDS system 20 is the level of the digital images upon which image analysis is performed. The classifiers are well established and tested on this lowest semantic level of the data network. The image analysis performed by the classifiers classifies objects in the digital images through a logic or algorithmic combination of different probability functions of different features.
At yet another level higher in the network, the image itself can be classified by the same principle. The image can be classified as an image with high or low quality or with respect to other criteria. In
In one example, CDS system 20 determines a first clinical action that was applied on a patient and then uses classifiers operating on the electronic health records of the patient and other patients to determine which second clinical action should also be applied on the patient. For example, where the first clinical action is acquiring an x-ray mammography of the patient, the CDS system 20 determines that a second clinical action should be performed on the patient, such as acquiring a magnetic resonance (MR) tomography.
A classifier uses image analysis on the x-ray mammography image to determine if an MR image would provide additional information compared to the x-ray alone. In other words, the CDS system 20 determines whether a diagnosis based on the x-ray alone is reliable. If the classifier determines that the x-ray diagnosis is reliable, then the classifier could suggest options such as (i) perform no additional clinical action because the x-ray indicates a benign lesion, or (ii) proceed with a biopsy to confirm the cancer diagnosis based on the x-ray.
Where an embodiment of the CDS system 20 is implemented in software, the functions of the software may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates the transfer of a computer program from one place to another. Storage media may be any available media that can be accessed by a computer. A hard disk of a server on which application 21 executes is an example of such a computer-readable medium. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer.
Although the present invention has been described in connection with certain specific embodiments for instructional purposes, the present invention is not limited thereto. Accordingly, various modifications, adaptations, and combinations of various features of the described embodiments can be practiced without departing from the scope of the invention as set forth in the claims.
This application is a continuation of, and claims priority under 35 U.S.C. §120 from, nonprovisional U.S. patent application Ser. No. 13/417,268 entitled “A Clinical Decision Support System,” filed on Mar. 11, 2012, the subject matter of which is incorporated herein by reference. Application Ser. No. 13/417,268, in turn, claims priority under 35 U.S.C. §119 from U.S. Provisional Application No. 61/464,948, entitled “A Clinical Decision Support System,” filed on Mar, 12, 2011, the subject matter of which is incorporated herein by reference.
Number | Date | Country | |
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61464948 | Mar 2011 | US |
Number | Date | Country | |
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Parent | 13417268 | Mar 2012 | US |
Child | 15443672 | US |