Using the IHE Scheduled Work Flow Integration Profile to Drive Modality Efficiency
Abstract
The IHE (Integrating the Healthcare Enterprise) Scheduled Work Flow integration profile describes a communication and work flow environment that provides benefits for radiology departments who want to standardize system software. The IHE technical framework defines this environment by specifying the systems involved and the messages exchanged by those systems. The Modality Worklist is a key component of the Scheduled Work Flow integration profile that allows an operator at each modality in the department to retrieve a list of scheduled procedure steps to perform and to automate the process of entering the correct patient identification information in all the images created with the modality. The IHE technical framework defines two transactions used by the modality to tell the Image Manager and Order Filler what was performed and how many images were acquired: the Modality Procedure Step in Progress and Modality Procedure Step Completed. Users who specify the Scheduled Work Flow integration profile will benefit immediately by achieving a certain baseline of functionality. However, users will derive further benefits of increased operational efficiency through negotiation with the providers of software solutions. The integration profile defines features that are optional; users should evaluate these features and request those that are determined to be beneficial.
© RSNA, 2003
Introduction
The IHE (Integrating the Healthcare Enterprise) initiative sponsored by the RSNA (Radiological Society of North America) and HIMSS (Healthcare Information and Management Systems Society) is designed to improve the integration of the information systems involved in important work flow processes in the hospital. IHE identifies the key transactions required to automate processes, reduce errors, and increase efficiency and groups them into integration profiles, each profile related to a specific operational work flow process in the enterprise. The IHE initiative and the initial seven integration profiles were described in a series of RadioGraphics primer articles (,1–,3). An article describing the year 4 additions to IHE was published in November 2002 RadioGraphics (,4). Other publications have discussed the IHE initiative and how system integration will lead to improved efficiency in a healthcare enterprise (,5).
The IHE integration profiles use accepted standards (DICOM [Digital Imaging and Communications in Medicine], HL7 [Health Level 7], and Internet Engineering Task Force Request for Comments) to communicate among the information systems in the enterprise. The transactions and data involved were selected to achieve specific operational goals; however, they can be used to achieve much more than their original purpose.
The Scheduled Work Flow integration profile is the foundation of the IHE effort. It is fundamental to achieving the significant integration benefits that IHE can provide. The IHE Scheduled Work Flow integration profile describes a communication and work flow environment that provides benefits for radiology departments that want to standardize system software. The IHE technical framework defines this environment by specifying the systems involved and the messages exchanged by those systems. However, as with many technical specifications, the IHE technical framework describes how things work but not necessarily why things work or how this is of benefit to the end user.
This article takes a slice of the Scheduled Work Flow integration profile and describes how features specified in the framework for acquisition modalities can be used to make both modalities and the systems they feed operate more efficiently. The article examines features that I believe should be present in systems that support Scheduled Work Flow and discusses how those features will benefit the healthcare enterprise. It also describes how systems can use these data to achieve more than IHE originally envisioned, providing a kind of “wish list” for customers to request and for vendors to implement to provide other important benefits to their customers.
The article is organized by the messages exchanged between systems. First, the messages and the systems involved are briefly described. Then, the work flow benefits of using these messages and the additional features that become possible when these messages are supported are discussed. The IHE technical framework defines specific actors that participate in transactions. These actor names are chosen to be different than traditional product classifications to allow vendors the flexibility to include diverse functionality in different types of systems. The three types of actors discussed herein are the Acquisition Modality, Department System Scheduler/Order Filler and Image Manager/Image Archive. For brevity, the terms Order Filler and Image Manager are used.
Modality Worklist Provided
The DICOM Modality Worklist is a key component of the Scheduled Work Flow integration profile. This feature allows an operator at each modality in the department to retrieve a list of scheduled procedure steps to perform (eg, all steps scheduled for a specific scanner, all steps scheduled for all magnetic resonance [MR] imagers) and to automate the process of entering the correct patient identification information in all the images created with the modality.
By providing improved accuracy in placing demographic and procedure information in the image headers, the functions of the Modality Worklist directly benefit the operations of the Image Manager. With the proper patient and study information in all the images, the radiologist can find and display both new and previous studies for any specific patient. The flow of information from the Order Filler through the Acquisition Modality to the Image Manager is shown in ,Figure 1.
In addition to these benefits for the radiologist, the use of a Modality Worklist increases the operational efficiency of the modality. The Modality Worklist provides the modality with an electronic list of procedure steps; each entry contains patient demographic information and procedure information that can be electronically copied rather than entered manually. The technologist thus realizes a small time gain for each study. In addition, the increased accuracy of the information results in fewer lost and repeat studies, further increasing operational efficiency.
The IHE technical framework mandates that the modality map a specific set of attributes from the Modality Worklist entry into the images and procedure notification messages produced for each acquisition. The IHE definitions provide a consistent mapping that is designed to be the same for all modalities. A customer can request this mapping simply by requiring the Scheduled Work Flow integration profile in a request for proposal for a new purchase or software upgrade.
An option in the Scheduled Work Flow integration profile may further improve efficiency in the imaging department. The Assisted Acquisition Protocol Setting option allows the Modality Worklist provider to supply detailed codes that can be used to define each scheduled procedure step. In some implementations, the Modality Worklist entry is used merely to provide a text description of the scheduled step (eg, computed tomography [CT] of the head). The technologist must take the time to read the description and select the proper protocol on the modality. If a modality supports the Assisted Acquisition Protocol Setting option, it can interpret the code values in the Modality Worklist entry and provide intelligent choices to the technologist. In the hypothetical implementation shown in ,Figure 2, the modality interprets the code value and presents the “several best protocol settings” to the technologist. The technologist then selects one of the settings offered or decides to override what is offered and selects a different setting. The benefit to the technologist is a shorter list of protocols to search through and a simpler procedure for configuring the modality.
The Assisted Acquisition Protocol Setting option is one of several options that can be specified as part of the Scheduled Work Flow integration profile. If this option would be valuable to you, you must request it specifically and complete several preparatory steps: (a) discuss with your Order Filler and modality vendor a plan for coordinating the code values sent in the Modality Worklist, (b) ascertain from the modality vendor how they will use the code values to determine the modality settings, and (c) determine how updates and additions to the codes will be handled. These steps may seem very detailed, but they can improve the efficiency of technologists at the modality.
Modality Procedure Step in Progress and Completed
Imagine what happens in many radiology departments today. A procedure is ordered and scheduled. The technologist at the modality performs the scheduled step or perhaps performs other steps upon the advice of the attending radiologist. At this point, images start to arrive at the Image Manager for interpretation by another radiologist who was not present during the procedure. To properly present these images to the radiologist for interpretation, the Image Manager must know (a) what procedure steps were really performed at the workstation, and (b) how many images were captured for each procedure step. To keep its records consistent with actual events, the Order Filler must know the answers to those same questions.
The IHE technical framework defines two transactions that are used by the modality to tell the Image Manager and Order Filler what was performed and how many images were acquired. These transactions are Modality Procedure Step in Progress and Modality Procedure Step Completed. This information is not available in the images generated by a modality.
As with the Modality Worklist Provided transaction, there are mandatory items that must be provided by the modality as well as optional items. Furthermore, the IHE technical framework requires that the Image Manager and Order Filler accept these messages but does not require that those systems to do anything intelligent with them (eg, “I see your e-mail attachment with a PDF file, but we don’t display PDF files in our e-mail system.”). The following sections describe mandatory and optional items in the Modality Performed Procedure Step messages that may be useful in the radiology department. However, you will need to ask specific questions of the vendors to make sure you derive the benefits of these messages. ,Figure 3 shows a possible sequence of messages from a modality to an Order Filler to an Image Manager and suggests some reports that could be generated based on these messages.
List of Images for Performed Procedure
All modalities are required to include a list of the images acquired for each performed procedure step. Radiologists no longer need to rely on the Image Manager vendor heuristics (eg, wait 10 minutes) to determine when the last image from a CT series has been received. The list gives the Image Manager a definitive signal for knowing when all the images for a specific step have been received. You will not know, however, when the study has been completed because the technologist is free to start another step at any time. But you will be able to view individual series with confidence that you have all the data. This distinction is important if the department provides image interpretation in real time; it is less important for institutions in which interpretation is performed in batch mode at a later time.
Automatic generation of these lists will allow the Order Filler to do some things that it might not be able to do currently. For example, if the Order Filler tracks the number of images taken for each procedure, the tracking could happen automatically rather than requiring the technologist to enter the information at an Order Filler terminal. In fact, you might even ask your vendor to perform the tracking for you. The IHE technical framework does not define this behavior, but you might want to ask your vendor to answer these questions: (a) for a given procedure, what is the average number of images acquired; (b) for that same procedure, are there any historical trends in the number of images acquired (eg, is there an increase every year and are the changes large?); (c) are there any differences in the number of images acquired for each technologist; and (d) can you infer anything about coverage of the imaged organs from these data?
Notification of Beginning and Ending the Procedure
All modalities are required to send both a start of procedure message and an end of procedure message. Intermediate status messages are allowed but are not required. These start and stop messages are received by the Order Filler and Image Manager, but there are no requirements that these systems use the information.
For example, you might want the Image Manager or Order Filler system to use the start and stop messages to provide a real-time display of the work being completed at each modality. The technologist knows when the scanner is not operating, but a manager may want access to this information to monitor the department. Furthermore, a record of utilization data for a scanner can be useful when maintenance issues must be discussed. In addition, a detailed log of scanner downtime is a useful item.
These start and stop messages could also be used to determine average scanning times for specific procedures. Such information could help you schedule your modalities more efficiently. Knowing when the imagers are scanning and when they are idle might help you determine the amount of time that the technologist spends with patient preparation versus scanning.
If you are interested in any of the applications just described, you will need to talk with not only the Image Manager and Order Filler vendor but also your modality vendor. The IHE technical framework requires the appropriate start and stop messages. However, a simplistic modality implementation could wait until the study is complete and then send both messages, one right after the other. This procedure is the equivalent for departments that track patients by logging both check-in and checkout as the patient leaves the department. The scanner should trigger the start message when the technologist begins the procedure step and should send the start message immediately. There should be no extra step or button for the technologist to push to initiate this message. Likewise, the stop message should be sent automatically when the technologist completes the procedure step. The modality user interface may require a specific operation from the technologist to indicate this step is complete.
Assisted Acquisition Protocol Setting
The Assisted Acquisition Protocol Setting is an option on the modality, Image Manager, and Order Filler. You must talk to all three vendors to receive the benefit of this option. As described above, the option allows the modality to use coded values from the Modality Worklist to better configure the system for scanning. The option also allows the modality to use the same coding system to tell the Order Filler and the Image Manager what was actually performed. For example, the scanner can tell those systems, “You told me to use protocol code ABC; the technologist used code XYZ instead.” If you want to track this information, you need to ask the Image Manager and Order Filler vendors how they will use the data. For example, the data could help those systems provide information to the radiologist at the time of interpretation. Furthermore, such information might be useful to the Order Filler when generating charge information.
You might also ask your Order Filler vendor how often the technologist performed what was actually scheduled. If technologists are routinely performing steps that are not scheduled, it might indicate that the wrong procedure is being ordered or possibly that the Order Filler is misconfigured and is placing the wrong codes in the Modality Worklist. In either case, presenting the wrong protocols to the technologist at the workstation is inefficient.
Other Options
Some vendor workstations support hanging protocols implemented in software. This software allows the workstation to display images according to user preference and procedure type. If this is important to you, you should ask your Image Manager vendor if the system supports such hanging protocols and if the procedure step messages are of any help.
Other optional items are defined for these procedure step messages but are not enumerated by the IHE technical framework. One example is the amount of dose administered during the procedure. If you want to track total dose administered to your patients, you need to ask if your Order Filler records that information for you.
Storage Commitment
The Storage Commitment transaction is a DICOM service included in the IHE technical framework to assist the modality with management of local storage. The following scenario illustrates the usefulness of Storage Commitment. A modality sends all images to an archive for storage, but for some reason the images for one study do not make it to the archive. As part of usual cleanup, the technologist prepares to delete old images from the modality at the end of the week. Without Storage Commitment, the images that did not make it to the archive would be lost. However, with Storage Commitment, the modality asks the Image Manager if it has taken responsibility for the images and has actually stored them. If the Image Manager agrees that the images are stored, the modality can then allow the user to delete the images, or the modality may choose to delete the images by some automated algorithm. ,,,Figure 4 shows hypothetical user interfaces for modalities without and with Storage Commitment.
You might want to ask both the modality and Image Manager vendors some of the following questions.
1. How often does the modality ask for Storage Commitment? Does it happen as each set of images is transmitted? Does it happen as a batch operation at night?
2. The Storage Commitment transaction is designed such that the response from the archive does not have to be immediate. How long will the archive take to respond to such a Storage Commitment request?
3. Does the modality automatically delete images that have been committed? If so, what is the algorithm for deleting the images? Are they deleted immediately or after 24 hours?
4. Does the modality allow only manual deletion of images? How does the technologist know what images have not been committed?
5. Does the modality automatically resend images that have not been committed? Does the archive want this behavior? Do you want this behavior?
6. How many days of cache does the modality support? Is there enough storage for 1 day, 2 days, 7 days? Is this long enough for the department? What happens with new CT sequences and thinner sections that double the number of images obtained?
Conclusions
Integrating software applications in the healthcare enterprise is a challenge that requires discussion and negotiation between both the users and the vendors selected to provide systems. The IHE technical framework provides an important set of definitions and work flow patterns that can be used to jump start these negotiations. If the representatives of the healthcare enterprise and vendors agree to use the definitions and work flow defined in the framework, then a large number of integration questions and specifications are already documented and do not need to be renegotiated and documented again by both parties.
The Scheduled Work Flow integration profile defines a work flow model involving several systems in the healthcare enterprise. Users who specify this integration profile will benefit immediately by achieving a certain baseline of functionality. However, users will derive further benefits through negotiation with the providers of software solutions. The integration profile defines features that are optional; users should evaluate these features and request those that are determined to be beneficial. Furthermore, some portions of the Scheduled Work Flow profile dictate that one system will provide specific data to another system that is downstream. However, the downstream system is not required to make use of these data. Users in the healthcare enterprise should discuss with their vendors how these standardized data can be used to benefit the hospital. Vendors might provide new innovations with these data or find they can solve problems without resorting to ad hoc methods.
Finally, the IHE technical framework imposes some requirements on the end users. A particular work flow model is defined by the framework, and the messages exchanged by systems reflect that model. Users will benefit only if they are committed to change their current work flow to match that defined in the framework. Such conformity will allow the user to request a standard software solution from multiple vendors rather than asking each vendor to customize software to match the work flow in the enterprise.
Figure 1. Acquisition Modality uses Modality Worklist information to generate images. The Acquisition Modality queries the Order Filler to obtain a list of the current work items. The modality uses the information to electronically copy patient name, patient identification number, date of birth, accession number, and other parameters that are placed in the images. The end user benefits by knowing the information has been accurately passed from the departmental system through the modality and on to the Image Manager.
Figure 2. Assisted Acquisition Protocol Setting option improves imager setup. The Modality Worklist entry for a procedure step description is a text description that a modality displays to the technologist. The Modality Worklist entry may also have patient history information. If the modality system can interpret the protocol code (MR9546), the imager software could automatically suggest one or more protocols for the procedure. The technologist could select one of the suggested protocols, if appropriate, thereby reducing imager setup time.
Figure 3. Modality Performed Procedure Step (MPPS) messages are sent to the Order Filler and Image Manager. As shown here, the modality sends MPPS messages to the Order Filler, which relays those messages to the Image Manager. An Order Filler could use the information to generate periodic reports of scanner usage or efficiency or to track historical trends in scanner parameters such as time required for specific procedures. An Order Filler could also have an alarm system to alert managers when a modality stops producing data. Finally, an Image Manager with integrated software would know that the modality produced 100 images for the current CT series and that all images were received.
Figure 4a. Storage Commitment enables automated disk management. (a) In a modality system without Storage Commitment, the technologist reviews the studies on the workstation and manually selects those to be deleted. If any study were not properly sent to the long-term archive, that study could be lost. (b) When a modality and Image Manager support Storage Commitment, the modality could present the technologist with a list of studies that are safe to delete. In our hypothetical user interface, the disk icon indicates the workstation has confirmed that the Image Manager has taken responsibility for the images. The workstation automatically activates the check boxes, allowing the user to “deselect” any study that needs to be retained. In the example, there is no check box for Thomas, and there is no storage icon. The modality does not allow the technologist to delete this study.
Figure 4b. Storage Commitment enables automated disk management. (a) In a modality system without Storage Commitment, the technologist reviews the studies on the workstation and manually selects those to be deleted. If any study were not properly sent to the long-term archive, that study could be lost. (b) When a modality and Image Manager support Storage Commitment, the modality could present the technologist with a list of studies that are safe to delete. In our hypothetical user interface, the disk icon indicates the workstation has confirmed that the Image Manager has taken responsibility for the images. The workstation automatically activates the check boxes, allowing the user to “deselect” any study that needs to be retained. In the example, there is no check box for Thomas, and there is no storage icon. The modality does not allow the technologist to delete this study.
Abbreviations: DICOM = Digital Imaging and Communications in Medicine, HIMSS = Healthcare Information and Management Systems Society, IHE = Integrating the Healthcare Enterprise
The author thanks Dr R. Gilbert Jost, John Perry, and Sanjay Jain for their review and comments. The author also thanks Dr G. James Blaine for his support and help with the RSNA IHE projects in our laboratory.
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