Scott L. DuVall, University of Utah; Richard H. Wiggins, III, MD; Aaron W.C. Kamauu, MD

The Integrating the Healthcare Enterprise (IHE) initiative aims to improve the way information is shared between applications. The Teaching File and Clinical Trial Export (TCE) integration profile defines how medical images and related information can be taken from picture archiving and communication system (PACS) to systems used for research and education. The Radiological Society of North America (RSNA) Medical Imaging Resource Center (MIRC) is an example of software that implements the TCE profile for its intended purpose.[1]

The IHE TCE profile involves three components that are called actors. They are an Export Selector, an Export Manager, and a Receiver. While the functionality of the Export Selector and Export Manager are closely defined, the behavior of the Receiver is not defined. This opens up the possibility that the same export method may be used for any application that can benefit from receiving images and related information from PACS. This has been shown to work in exporting images to publication systems.[2] We describe a generic implementation of a Receiver, the Global Receiver, that can be used to allow any application to receive images and related information from an IHE TCE-compliant system.

The Global Receiver is a Java application that implements the IHE TCE profile. As a TCE-compliant Receiver, it receives Digital Imaging and Communications in Medicine (DICOM) images and two types of DICOM structured reports: (1) a manifest, which contains the disposition of the information sent and (2) a list of identifiers referencing each object that is part of the transfer, and an Additional Teaching File Information (ATFI) report, which can contain details about the clinical case including diagnosis, anatomy, pathology, and case history. Because there is no guarantee that information will arrive at the same time or in a specific order, the Global Receiver handles each type of object separately. Each DICOM object contains a globally unique identifier (UID) that is referenced in the manifest.[3] As such, objects can be grouped together and saved in draft mode until all information is received.

When an image arrives, the UID is recorded and searched against all manifests saved in draft mode. If the manifest that references the image has already arrived, the image is assigned to that case. If no known manifest references the image, it remains in temporary storage waiting for its manifest to arrive. Similarly, when an ATFI report arrives, its UID is searched against known manifests. The report is assigned to the appropriate case or held until the correct manifest arrives.

When a manifest arrives, the UID of each image and ATFI report referenced is compared with those in temporary storage, where the manifest will also remain until all remaining referenced objects are accounted for. When all objects have arrived, the case is ready for processing.

Institutions wanting to implement TCE functionality previously would have to build custom Receivers that could interact with legacy systems. In order to provide generalized functionality, the Global Receiver has a configuration file that controls its behavior, including the following options:

Export Location:

Many applications use a directory structure to organize data. This is common in web applications where each directory may contain a single case. Other applications use a specific file location as a staging area for data needing to be imported. The Global Receiver configuration file allows an organization to specify a location where received files will be placed and provides options for which type of directory structure the files should be saved under.

Image Format:

The Global Receiver provides flexibility regarding the format in which medical images will be saved. Applications that perform image segmentation or 3-D reconstruction may require the original DICOM format, while web applications and those with common image viewing capability may require a standard desktop publishing format. The configuration file allows an organization to set the resolution and format in which the incoming images will be saved.

ATFI Export:

The ATFI report contains information regarding the clinical, research, or educational focus of the case. The ATFI report can be exported as an Extensible Markup Language (XML) file that can be linked to standard terminology and mapped to application data models. The ATFI report can also be exported as a DICOM structured report or as plain text.

Manifest Export:

While the manifest lists all objects in a case, it is not usually considered part of the case. In instances where this information is desired, the configuration file allows an organization to determine whether the manifest is stored as a DICOM structured report, an XML file, or as plain text.

The Global Receiver was used successfully to transfer medical images and related information from PACS to a teaching file developed within the Department of Radiology and a third party publication system.

The Global Receiver provides an easy and effective way for any application that could benefit from receiving images and related information from PACS to become IHE TCE-compliant. It is our intent to release the Global Receiver as an open-source software project.

[1] The Radiological Society of North America. MIRC Administrator's Manual. Available at: http://mircwiki.rsna.org/index.php?title=MIRC_Administrator's_Manual.

[2] Kamauu AWC, Whipple JJ, DuVall SL, Siddiqui KM, Siegel EL, Avrin DE. Informatics in radiology: IHE teaching file and clinical trial export integration profile: functional examples. Radiographics. July-August 2008;28(4):933-45.

[3] Kamauu AW, Duvall SL, Avrin DE. Using Java to Generate Globally Unique Identifiers for DICOM Objects. J Digit Imaging. September 2007;25. [Epub ahead of print]