Wyatt M. Tellis

Reducing the Rate of Repeat Imaging: Import of Outside Images to PACS

OBJECTIVE Repeat imaging at the transfer of care between institutions is a potential source of overutilization. The purpose of this study was to assess whether importing images obtained at one institution to the PACS at another institution reduces the number of repeat imaging examinations performed, sparing patients unnecessary cost and radiation. MATERIALS AND METHODS Informed consent was waived for this retrospective study, which included 267 patients who had undergone CT or MRI of the abdomen at our or another institution within 4 months before transarterial chemoembolization. Patients were divided into the following four groups based on the availability of their images from institutions other than ours (outside images): outside imaging performed but images not available; outside images available on CD or film but not imported; outside images imported to PACS; and no outside imaging, that is, all imaging performed at our institution. The rates of repeat imaging in the four groups were compared. RESULTS When outside images were not available, 72% (13/18) of patients underwent repeat imaging; when outside images were available but not imported, 52% (14/27); when outside images were imported to PACS, 11% (9/79); and when imaging was performed only at our institution, 13% (18/143). Patients whose outside images were imported were significantly less likely to undergo repeat imaging than were both groups whose outside images were not imported (p < 0.001), and their rate of repeat imaging was similar to that of patients who did not undergo outside imaging (p = 0.79). After adjustment for potential confounders, including age, sex, referring institution, and size and number of lesions, the odds that a patient whose images were imported would undergo repeat imaging were significantly lower than those of a patient whose outside images were not imported (odds ratios, 31 for images not available and 9.0 for images available but not imported; both p < 0.001) and were similar to those of a patient who underwent all imaging at our institution (odds ratio, 0.71; p = 0.51). CONCLUSION Importing outside images to PACS reduces the rate of repeat imaging.

Implementing a MIRC Query Interface for a Database Driven Teaching File

This paper describes the authors’ experience with integrating an existing database-driven teaching file with the RSNA (Radiological Society of North America) Medical Imaging Resource Center (MIRC). MIRC is the product of an RSNA-sponsored initiative to enable medical institutions to share their electronic medical content (images, text, and multimedia) by creating a distributed repository accessible from the Internet. An existing database-driven teaching file, developed by the authors and used extensively by the University of California San Francisco (UCSF) Department of Radiology since 1998, was retrofitted to include an interface for handling broadcast queries initiated by a MIRC query service. These queries take place through the exchange of XML documents via HTTP. After all the storage services have responded, the results are collated by the query service and presented to the user. The teaching file and MIRC interface were developed using the 4th Dimension Relational Database Management System (RDBMS). The integration process primarily involved mapping the “MIRCdocument” schema to the teaching file’s schema, translating the actual MIRC query into the internal query language of the database and extending the access control mechanisms of the teaching file to allow public access. A working implementation of the interface required only 3 days of development time, with refinements taking place over several months. Interface development was greatly aided by MIRC’s use of well-established Internet standards. This project has demonstrated the feasibility of implementing a MIRC interface on an existing teaching file server.

The RSNA Image Sharing Network

In the era of health information exchanges, there are trade-offs to consider when sharing a patient’s medical record among all providers that a patient might choose. Exchange among in-network partners on the same electronic medical records (EMR) and other integrated information systems is trivial. The patient identifier is common, as are the relevant departmental systems, to all providers. Difficulties arise when patient records including images (and reports) must be shared among different networks and even with the patients themselves. The National Institutes of Health (NIH) challenged Radiological Society of North America (RSNA) to develop a transport method that could supersede the need for physical media (for patients or other providers), replace point-to-point private networks among providers, and enable image exchange on an ad hoc basis between arbitrary health networks without long legal delays. In concert with the evolving US health care paradigm, patient engagement was to be fundamental. With Integrating Healthcare Enterprise’s (IHE’s) help, the challenge has been met with an operational system.

Finding the optimal picture archvingand communciation system(PACS)architecture: A comparison of three PACS designs

Purpose: At present, there are two basic picture archiving and communication system (PACS) architectures: centralized with a central cache and controller, and distributed with a distributed cache and central controller. A third architecture proposed here is an autonomous one with a distributed cache and no controller. This report will investigate the performance (as measured be central processing unit [CPU] and networkload, scalability, and examination retrieval and display latency) of these three types.Methods: The distributed PACS architecture will be simulated using an IM PAX R3.5 (AGFA, Ridgefield Park, NJ) PACS, while the centralized design will be simulated using an IMPAX R4 (AGFA) PACS. The autonomous system will be designed and implementedin-house. The autonomous system consists of two types of entities: basic components such as acquisition gateways, display stations, and long-term archives, and registry servers, which store global state information about the individual PACS components. The key feature of the autonomous system will be the replacement of the central PACS controller by the registry servers. In this scenario the registry servers monitor the interactions between the components, but do not directly govern them. Instead each component will contain the application logic it requires and will use the state information from the registry servers to take the appropriate action, such as routing images, prefetching studies, and expiring images from near line cache. In addition the routing of examinations will be optimized to reduce the duplication of image data. Display stations will be categorized by specialty (neuroradiology, pediatrics, chest, etc) and will retrieve studies for display on demand from intermediate servers dedicated to the corresponding specialty. Studies will be routed only to the intermediate servers and not to display stations.Results: By distributing the application logic, an autonomous PACS architecture can provide increased fault tolerance and therefore increased uptime. In addition, the lack of a central controller and the use of intermediate servers improve the scalability of the system, as well as reduce CPU and network loads.

Patient-directed Internet-based Medical Image Exchange:

RATIONALE AND OBJECTIVES Inefficient transfer of personal health records among providers negatively impacts quality of health care and increases cost. This multicenter study evaluates the implementation of the first Internet-based image-sharing system that gives patients ownership and control of their imaging exams, including assessment of patient satisfaction. MATERIALS AND METHODS Patients receiving any medical imaging exams in four academic centers were eligible to have images uploaded into an online, Internet-based personal health record. Satisfaction surveys were provided during recruitment with questions on ease of use, privacy and security, and timeliness of access to images. Responses were rated on a five-point scale and compared using logistic regression and McNemars test. RESULTS A total of 2562 patients enrolled from July 2012 to August 2013. The median number of imaging exams uploaded per patient was 5. Most commonly, exams were plain X-rays (34.7%), computed tomography (25.7%), and magnetic resonance imaging (16.1%). Of 502 (19.6%) patient surveys returned, 448 indicated the method of image sharing (Internet, compact discs [CDs], both, other). Nearly all patients (96.5%) responded favorably to having direct access to images, and 78% reported viewing their medical images independently. There was no difference between Internet and CD users in satisfaction with privacy and security and timeliness of access to medical images. A greater percentage of Internet users compared to CD users reported access without difficulty (88.3% vs. 77.5%, P < 0.0001). CONCLUSION A patient-directed, interoperable, Internet-based image-sharing system is feasible and surpasses the use of CDs with respect to accessibility of imaging exams while generating similar satisfaction with respect to privacy.

Integrating Multiple Clinical Information Systems using the Java Message Service Framework to Enable the Delivery of Urgent Exam Results at the Point of Care

The aim of this study is to determine if network-enabled personal digital assistants (PDAs) can be used to facilitate the timely delivery of urgent radiological exam results by reducing the interval from when the radiologists initial interpretation is available to when it is first viewed by an emergency department (ED) physician. A web- and Java message service (JMS)-based application was built to replace the original fax-based wet-read procedure. The new system allows radiologists to enter wet-reads from the picture archiving and communication system (PACS) display station and to track discrepancies between the wet-read and final report. It also notifies the ED physicians when exam results are available via the PDAs and permits them to view the full text of the wet-read and final reports from the devices. The new system is compared to the original procedure with the results showing improvements with the wireless method. Furthermore, feedback from a qualitative survey of PDA users was positive, suggesting that PDAs may provide one means for accessing urgent clinical data at the point of care.

Integrating multiple clinical information systems using the Java Message Service framework

This article describes an application for capturing, delivering, and tracking urgent radiology exam results. Urgent exam findings are entered using a Web form embedded within the Picture archiving and communication system (PACS) display station. The findings are then accessible via soft copy using the PACS display stations, hospital information system (HIS) terminals, or wireless-enabled personal digital assistants (PDAs) or via hard copy printouts that are generated automatically or on demand. Additionally, quality control is performed on those findings entered by radiology residents and fellows, the results of which are used for both performance tracking and educational activities. The application was developed using Sun Microsystems’ Java programming language. The Java Message Service (JMS) was used to manage the delivery of findings. JMS provides a robust, flexible framework for exchanging messages between disparate applications. The application is now used for all urgent exams; completely replacing the original paper-based system. The use of JMS provides the necessary level of reliability needed by this application.

What Digital Imaging and Communication in Medicine (DICOM) Could Look Like in Common Object Request Broker (CORBA) and Extensible Markup Language (XML)

Common object request broker architecture (CORBA) is a method for invoking distributed objects across a network. There has been some activity in applying this software technology to Digital Imaging and Communications in Medicine (DICOM), but no documented demonstration of how this would actually work. We report a CORBA demonstration that is functionally equivalent and in some ways superior to the DICOM communication protocol. In addition, in and outside of medicine, there is great interest in the use of extensible markup language (XML) to provide interoperation between databases. An example implementation of the DICOM data structure in XML will also be demonstrated. Using Visibroker ORB from Inprise (Scotts Valley, CA), a test bed was developed to simulate the principle DICOM operations: store, query, and retrieve (SQR). SQR is the most common interaction between a modality device application entity (AE) such as a computed tomography (CT) scanner, and a storage component, as well as between a storage component and a workstation. The storage of a CT study by invoking one of several storage objects residing on a network was simulated and demonstrated. In addition, XML database descriptors were used to facilitate the transfer of DICOM header information between independent databases. CORBA is demonstrated to have great potential for the next version of DICOM. It can provide redundant protection against single points of failure. XML appears to be an excellent method of providing interaction between separate databases managing the DICOM information object model, and may therefore eliminate the common use of proprietary client-server databases in commercial implementations of picture archiving and communication systems (PACS).

Network latency and operator performance in teleradiology applications.

Teleradiology applications often use an interactive conferencing mode with remote control mouse pointers. When a telephone is used for voice communication, latencies of the data network can create a temporal discrepancy between the position of the mouse pointer and the verbal communication. To assess the effects of this dissociation, we examined the performance of 5 test persons carrying out simple teleradiology tasks under varying simulated network conditions. When the network latency exceeded 400 milliseconds, the performance of the test persons dropped, and an increasing number of errors were made. This effect was the same for constant latencies, which can occur on the network path, and for variable delays caused by the Nagle algorithm, an internal buffering scheme used by the TCP/IP protocol. Because the Nagle algorithm used in typical TCP/IP implementations causes a latency of about 300 milliseconds even before a data packet is sent, any additional latency in the network of 100 milliseconds or more will result in a decreased operator performance in teleradiology applications. These conditions frequently occur on the public Internet or on overseas connections. For optimal performance, the authors recommend bypassing the Nagle algorithm in teleradiology applications.

Secure, web-accessible call rosters for academic radiology departments.

Traditionally, radiology department call rosters have been posted via paper and bulletin boards. Frequently, changes to these lists are made by multiple people independently, but often not synchronized, resulting in confusion among the house staff and technical staff as to who is on call and when. In addition, multiple and disparate copies exist in different sections of the department, and changes made would not be propagated to all the schedules. To eliminate such difficulties, a paperless call scheduling application was developed. Our call scheduling program allowed Javaenabled web access to a database by designated personnel from each radiology section who have privileges to make the necessary changes. Once a person made a change, everyone accessing the data-base would see the modification. This eliminates the chaos resulting from people swapping shifts at the last minute and not having the time to record or broadcast the change. Furthermore, all changes to the database were logged. Users are given a log-in name and password and can only edit their section; however, all personnel have access to all sections’ schedules. Our applet was written in Java 2 using the latest technology in database access. We access our Interbase database through the DataExpress and DB Swing (Borland, Scotts Valley, CA) components. The result is secure access to the call rosters via the web. There are many advantages to the web-enabled access, mainly the ability for people to make changes and have the changes recorded and propagated in a single virtual location and available to all who need to know.