DOI: 10.1148/rg.271065110
RadioGraphics 2007;27:269-275
© RSNA, 2007
Informatics in Radiology
Use of the MIRC DICOM Service for Clinical Trials to Automatically Create Teaching File Cases from PACS1
Amilcare Gentili, MD,
Christine B. Chung, MD and
Tudor Hughes, MD
1 From the Department of Radiology, University of California, San Diego–Thornton Hospital and San Diego Veterans Affairs Medical Center, 9300 Campus Point Dr, La Jolla, CA 92037. Presented as an infoRAD exhibit at the 2005 RSNA Annual Meeting. Received June 5, 2006; revision requested July 13 and received August 16; accepted September 8. All authors have no financial relationships to disclose.
Address correspondence to A.G. (e-mail: agentili{at}ucsd.edu).
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Abstract
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The Medical Imaging Resource Center (MIRC) software of the Radiological Society of North America is used to share teaching files and clinical trial data. By using the MIRC service for clinical trials, teaching file cases can be automatically generated directly from picture archiving and communication systems (PACS). The advantage of using the clinical trials service over the authoring service is the need for minimal user intervention, because data already present in the Digital Imaging and Communications in Medicine (DICOM) header can be automatically inserted into teaching file cases. When reading a case on the PACS workstation, the radiologist needs only to select the images for the teaching file case, write the diagnosis in the "Study Comments" box (usually used for "wet" readings), and send the case to the MIRC server directly from the workstation. The MIRC server automatically makes the images anonymous and fills in the modified teaching file template by using the data in the DICOM header (patient age, patient sex, clinical history, diagnosis, imaging modality, organ system), thus creating a simple teaching file. If desired, the teaching file case can be edited at a later time. By making minor modifications to the MIRC DICOM clinical trials service, it is possible to create teaching file cases with minimal effort. Supplemental material available at radiographics.rsnajnls.org/cgi/content/full/27/1/269/DC1.
© RSNA, 2007
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Introduction
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Teaching files are present in most radiology departments. Radiologists have always collected interesting cases for teaching purposes or for use in presentations and publications. In the past, these teaching files were made of hard-copy film images. With the advent of picture archiving and communication systems (PACS) and the disappearance of film images, teaching files have become digital (1). Several systems have been used to create and distribute these digital teaching files over the Internet (1–11). The ideal teaching file system should allow creation of teaching files at the PACS workstation as part of the routine work flow. Radiologists should be able to create a teaching file case when they see an interesting case for the first time during a reading session, without significantly disrupting the clinical work (1). The system should require minimal training to use and should be inexpensive.
In this article, we describe an approach to integrating teaching file creation into the routine clinical work flow with minimal disruption of the clinical work. We use the Medical Imaging Resource Center (MIRC) software of the Radiological Society of North America (RSNA) (12) for creation, storage, and distribution of teaching file cases. In addition, we take advantage of the capability of our current PACS (Agfa, Teterboro, NJ) to annotate studies and send images in Digital Imaging and Communications in Medicine (DICOM) format to other DICOM storage service class providers during the clinical reading sessions. This system allows radiologists to identify interesting cases and submit them to the teaching file server for automatic creation of simple teaching file cases. These cases are created by using the information available in the DICOM header.
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Medical Imaging Resource Center
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The RSNA initiated the MIRC project to facilitate sharing of medical information throughout the imaging community. Documents conforming to the "MIRCdocument" schema (13) can be easily indexed and shared over the Internet. The RSNA has developed software necessary to implement a MIRC site server capable of indexing and distributing extensible markup language (XML) documents conforming to the MIRC-document schema (14) (Fig 1). This software is open source and can be downloaded free of charge from the RSNA. The MIRC site software is written in Java (Sun Microsystems, Mountain View, Calif) and runs on Linux, Mac OS X (Apple Computer, Cupertino, Calif), and Windows (Microsoft, Redmond, Wash) operating systems. It requires that Java 2 SDK 1.5 and Tomcat 5.5 (Apache Software Foundation, Forest Hill, Md) be present on the system where the MIRC site software is being installed.
The MIRC site includes three primary components: the query service, the file service, and the storage service. The storage service contains numerous servlets, including an author service, a DICOM service, a document submission service, an administration service, a storage service, and an XML server. Either the author service or the document submission service is usually used for creation of teaching files. The authoring service is a server-side authoring tool that allows creation and editing of teaching file cases online. When the authoring service is used, the authors do not need to install any software on their computers; all editing is done through a Web browser interface. On the other hand, the document submission service receives documents from client-side authoring tools and inserts them into the MIRC system. Several client-side applications are available; some are free while others are commercially available. Examples of free tools include MIRCat, a stand-alone Java program developed by the RSNA to author and submit new teaching cases to the MIRC server, and SimpleMIRC (15), a freeware utility developed at the University of Pittsburgh, Pa. Commercially available tools include RadPix (Weadock Software, Ann Arbor, Mich) and RadXtreme (Tesla9, St Louis, Mo).
The DICOM service for clinical trials was designed to create DICOM objects used in clinical trials based on settings stored in the "template.xml" file. We found that with minor modifications to the template.xml file, the DICOM service for clinical trials can be used to automatically create teaching files. After installation of the MIRC site software, the MIRC DICOM service for clinical trials is configured to accept images from PACS (16) (a DICOM Store AE [Application Entity] Title and port number are assigned to the MIRC storage service). The MIRC site is entered in PACS as a DICOM store destination. The anonymizer for MIRC clinical trial services is configured to remove protected patient information, but to retain certain data such as clinical history, imaging modality, organ system, and study comments. After installation of the MIRC server software and configuration of the clinical trial service, we modified the template.xml file, combining it with the teaching file template provided with the author service.
To comply with Health Insurance Portability and Accountability Act (HIPAA) regulations, protected patient information is removed from the template, while the clinical history and diagnosis are added. When the DICOM service for clinical trials receives DICOM images, it automatically creates MIRC documents based on the DICOM headers of the images and the configuration file template.xml (see Appendix E1 at radiographics.rsnajnls.org/cgi/content/full/27/1/269/DC1).
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Creation of a Teaching File Case
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Once the system is properly configured, it is very easy to create a teaching file (Fig 2). When the radiologist sees an interesting case on the PACS workstation, he or she selects the images for the teaching file case, writes the diagnosis in the "Study Comments" box (usually used for wet readings), and sends the case to the MIRC site directly from the PACS, taking advantage of the capability of the PACS to transmit images. This process requires only typing the diagnosis and a few clicks to select and transmit the images and does not significantly slow down the radiologist.
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Figure 2. Screen of a PACS workstation shows creation of a teaching file case. First, the interesting images are selected (white arrow). Second, the diagnosis is typed in the "Study Comments" box (black arrow). Third, the MIRC teaching file server is selected as a destination (white arrowhead) and the images are transmitted.
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Once the images are sent to the MIRC site, the DICOM service for clinical trials automatically creates a simple teaching file, filling the modified teaching file template using the data in the DICOM header (Table, Fig 3). Each new case includes the patient age, patient sex, clinical history, diagnosis, imaging modality, and organ system (Fig 4). The MIRC clinical trials software automatically creates three or four copies of each image: a DICOM image stripped of protected patient information and two or three JPEG images. The JPEG images include a thumbnail image, an image of the same size as the original, and an image of the size specified by the configuration file template.xml, if the value specified in the template is smaller than the original image size. The DICOM image can be windowed and leveled by the user using a Java applet built into the MIRC server. The JPEG images are saved with the same window and level saved as defaults in the PACS.
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Figure 3. Work flow for creation of teaching files. 1. The images for the teaching file are selected on the PACS workstation. 2. The selected images are transmitted to the MIRC server. 3. The MIRC server removes protected patient information, imports information from the DICOM header into the MIRC document, saves a copy of the DICOM images, and creates Joint Photographic Experts Group (JPEG) copies of the images. 4. The teaching case can be reviewed or edited from any personal computer (PC) on the intranet.
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The MIRC server administrator can set up the server to immediately index new cases and make them available on the intranet, or may require approval before a case is indexed and released. If desired, the automatically created teaching file cases can be edited at a later time by using the MIRC author service; additional data such as description of findings, differential diagnosis, references, and even a quiz can be added (Fig 5). The images can also be annotated at a later time.
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Discussion
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Several tools have been developed to assist the radiologist in creating digital teaching files, such as RadPix, RadXtreme, SimpleMIRC, Casimage (Idem Informatique, Geneva, Switzerland), and MyPACS.com (Vivalog Technologies, Seattle, Wash). The advantage of our method is that the radiologist can create a simple teaching case without disruption of the reading session, as it takes only a few mouse clicks to create the case. Our system has a limited scope: It can only create a simple teaching file, and any further editing is left to the authoring service of the MIRC server. It does not include any image editing tool to rotate, crop, enlarge, or edit images. Rotating of the images and adjusting the gray scale has to be done on the PACS before sending the images to the MIRC server. Other tools such as RadPix and RadXtreme not only include image editing tools, but also let the user convert series of images to audio video interleave (AVI) movies and can connect to Microsoft PowerPoint to convert Power-Point documents to MIRC documents and MIRC documents to PowerPoint format.
Our methodology has been tested only with our current PACS vendor but should work with other PACS systems, as it uses standard DICOM features. A PACS system to take advantage of this method needs to be able to edit the DICOM "Study Comments" field and transmit DICOM images to other DICOM storage service class providers.
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Conclusions
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The advantage of using the clinical trial service over the authoring service for creation of teaching files is the need for minimal user intervention. Data already present in the DICOM header can be automatically inserted into teaching file cases.
Since we configured the MIRC server to automatically create teaching file cases, the number of teaching file cases submitted to our section’s MIRC server has greatly increased from one case a month to one case a day. Our teaching file is used as a repository of images for lectures and publications by our faculty members and by the residents to review interesting cases during their musculoskeletal rotation.
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TAKE-HOME POINTS
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- The ideal teaching file system should allow creation of teaching files at the PACS workstation as part of the routine work flow.
- The RSNA initiated the MIRC project to facilitate sharing of medical information throughout the imaging community. Documents conforming to the "MIRCdocument" schema can be easily indexed and shared over the Internet.
- The DICOM service for clinical trials was designed to create DICOM objects used in clinical trials based on settings stored in the "template.xml" file. We found that with minor modifications to the template.xml file, the DICOM service for clinical trials can be used to automatically create teaching files.
- The advantage of using the clinical trial service over the authoring service for creation of teaching files is the need for minimal user intervention. Data already present in the DICOM header can be automatically inserted into teaching file cases.
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Footnotes
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Abbreviations: DICOM = Digital Imaging and Communications in Medicine, JPEG = Joint Photographic Experts Group, MIRC = Medical Imaging Resource Center, PACS = picture archiving and communication system, RSNA = Radiological Society of North America
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References
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Abstract
Introduction
