DOI: 10.1148/rg.236035074
(Radiographics. 2003;23:1683-1687.)
© RSNA, 2003
Extending PowerPoint with DICOM Image Support1
Masoom A. Haider, MD, FRCP(C)
1 From the Joint Department of Medical Imaging, University Health Network and Mount Sinai Hospital, University of Toronto, Ontario, Canada. Recipient of a Cum Laude award for an infoRAD exhibit at the 2002 RSNA scientific assembly. Received March 19, 2003; revision requested May 6; revision received May 13; accepted May 29. Address correspondence to the author, Department of Medical Imaging, Princess Margaret Hospital, 610 University Ave, Rm 3–958, Toronto, Ontario, Canada M5G 2M9 (e-mail: m.haider@utoronto.ca).
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Abstract
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Although PowerPoint has become a ubiquitous presentation tool in medical imaging, it does not support the Digital Imaging and Communications in Medicine (DICOM) standard. Users must go through a laborious conversion process that includes guessing the appropriate brightness and contrast to convert 16-bit DICOM images into 8-bit formats. A PowerPoint add-in was developed that incorporates features of a DICOM viewer into a presentation. Users can interactively manipulate large series of 16-bit images in stack mode with scroll, crop, zoom, and window width and level functions, as well as sort through images by location or series. Multiple DICOM image series can be placed on a single slide, and one can interactively scroll through stacks of images during a presentation to demonstrate imaging findings. The problem created by the varying contrast and brightness of different projector systems is overcome by interactively adjusting the image window level during presentations. Bone and lung window views can be shown without having to create separate images. Combining DICOM images into stacks as part of a PowerPoint presentation can result in a more effective and higher-quality presentation of medical images.
© RSNA, 2003
Index Terms: Computers, educational aid • Computers, multimedia • Digital imaging and communications in medicine (DICOM)
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Introduction
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PowerPoint (Microsoft, Redmond, Wash) has become a standard software tool throughout the radiology community for making presentations (1). Although Digital Imaging and Communications in Medicine (DICOM) is the standard for the storage and networking of medical images, it is not supported by most of the commonly used nonmedical commercial software, including PowerPoint. Consequently, a multistep conversion process is required to translate DICOM images into formats that can be used for presentations (2–6). This conversion process involves selecting a specific window width and level to convert 12- or 16-bit DICOM data into 8-bit data for PowerPoint. As a result, the ability to see the full dynamic range of gray-scale information in an image is lost (212 levels of gray can be represented with 12-bit data and 28 levels with 8-bit data). For a computed tomographic (CT) scan, lung window, bone window, and soft-tissue window images must be generated separately. Similarly, for a mammogram, two window level settings need to be used: one to show subtle microcalcifications and another to show lesion morphology. The contrast and brightness of computer projectors can vary widely. Thus, it is not unusual for an image that looked good on one’s laptop to be too bright, too dark, or have incorrect contrast when it is projected in front of an audience, and one has no means of correcting this situation during the presentation. Consequently, the conversion process from DICOM images to PowerPoint-compatible images can result in a suboptimal presentation of imaging findings.
The way in which radiologists view and interpret images is changing with the increasing use of computer workstations. Scrolling through stacks of images and adjusting window width and level settings is common practice for cross-sectional studies such as CT and magnetic resonance (MR) imaging (7,8). As a result, presenting a single image has become much less effective than presenting a stack of images that one can scroll through. Radiology trainees often have difficulty interpreting single cross-sectional images and are much more comfortable scrolling through image stacks. In the teaching environment, one is faced with a situation in which manipulating an image to show findings can inadvertently reveal the diagnosis. Presenting a case as it would be presented in the real clinical environment at a workstation becomes impossible if one is using PowerPoint.
A DICOM viewer typically provides functionality that includes real-time scrolling through image stacks, crop and zoom functions, and adjustment of window width and level settings. If DICOM data and the functionality of viewing software could be combined on a PowerPoint slide, the effectiveness of PowerPoint as an educational and presentation tool for radiologists could be markedly improved. In this article, I discuss and illustrate a tool that adds the functionality of a DICOM viewer to PowerPoint.
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Methods
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Development of the DICOM Component
Microsoft has provided a method for extending the functionality of its Office applications (such as PowerPoint) through add-ins and ActiveX components. An add-in and ActiveX component were constructed that extend PowerPoint capabilities to support DICOM images. This software is called DICOM for PowerPoint. The first step in development was implementation of a DICOM ActiveX component, which was accomplished with a combination of Microsoft Visual Basic v6.0 and Microsoft Visual C++ v6.0. The next step was to develop a plug-in for PowerPoint that allowed integration of the ActiveX component into the presentation design mode. This step was accomplished with Visual Basic for Applications in Microsoft Office. Finally, an installation and setup program was constructed to ensure that all necessary components could be installed easily.
Storing Images
In moving presentations from one computer to another, it is important to understand how DICOM images are stored by DICOM for PowerPoint. For a given presentation called "presentation_name," all DICOM images would be stored in a folder called "presentation name_ DICOM" in the same location on the user’s computer as the presentation. To move the PowerPoint presentation to another computer, the user would move both the presentation and the accompanying DICOM folder. The DICOM folder and the presentation must be kept together. And, of course, DICOM for PowerPoint must be installed on the new computer for DICOM images to be displayed correctly.
Installing the DICOM for PowerPoint Add-In
The user must run the installation program once on a host machine to extend the functionality of PowerPoint 2000 or XP. The installer can be downloaded for free from www.radfiler.com/dicomppt.htm. Once the program is installed, PowerPoint will be able to handle DICOM images. As with most software installations, the user must have Administrative privileges (an account type in Microsoft Windows) if installation is being performed on a Windows NT/2000 or XP platform (Microsoft). In addition, the security setting in PowerPoint should be set to "low" to enable macros to run.
Importing Images
After installation is complete, the user will see two additional items on the Tools menu: "Add DICOM Image" and "Edit DICOM Image." By taking the following steps, the user can add a DICOM stack to a PowerPoint slide (Fig 1):
- Create a new slide or move to an existing slide in a presentation.
- Select "Add DICOM Image" from the Tools menu.
- Select the folder containing the DICOM images. All DICOM images should be in this folder and named with a .dcm extension (eg, image01.dcm, image02.dcm, image03.dcm, and so on).
- A viewer interface with a stack of images will appear. This image stack may be edited for presentation.
- Once editing is complete, close the viewer and place and resize the frame containing the images on the slide.
Manipulating Image Stacks
Images can be manipulated in a number of ways at the time the slide is being created or during the presentation. Editing functions are provided through a toolbar (Fig 2), which can be made visible or invisible by double-clicking anywhere on the image. The following capabilities are provided: (a) adjusting window width and level (with CT presets for lung, bone, abdomen, and so on) by moving the mouse with the right mouse button depressed, (b) scrolling through stacks of images by moving the mouse vertically with the left mouse button depressed, (c) sorting through images by location or number as provided in the DICOM header by means of a drop-down menu, and (d) zooming and cropping by drawing a selection box with the left mouse button depressed after clicking on the magnification icon on the toolbar.
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Figure 2. Portion of a computer screen illustrates the toolbar. The toolbar can be activated in the DICOM edit window at the time a presentation is being designed or during the presentation itself by double-clicking with the left mouse button anywhere on an image. Each toolbar button has functionality as indicated by the arrows, with some buttons having drop-down menus.
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Having these functions available at the time the presentation is being designed as well as during the actual presentation has its advantages. The user can define the initial image size and cropping, image order, and window width and level settings. At the time of presentation, the user is not bound by these initial choices and can interactively adjust the window width and level—for example, to switch between lung and soft-tissue windows or to compensate for an overly bright projector. The presenter can also scroll through stacks of images with complete control, going back and forth with variable speed, unlike with the commonly used video files (ie, Audio Video Interleave [AVI], Moving Picture Experts Group [MPEG]). Similarly, the user can zoom in on a key area of interest, which can make for a very effective interactive demonstration of imaging findings.
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Discussion
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Although the incorporation of DICOM viewer features into PowerPoint has its advantages, it also has some limitations. At large conferences, centralized servers or a single machine is commonly used to store presentations to prevent wasting time switching laptops at the podium. If the host machine does not have DICOM for PowerPoint installed, the presentation will not run properly. Thus, the user should arrange for the installation of DICOM for PowerPoint in advance.
Uncompressed DICOM files can be very large. For example, a typical CT scan is 512 Kbytes (as opposed to a digital mammogram, which is approximately 8 Mbytes). A typical recordable CD (CD-R) stores 650 Mbytes. Thus, approximately 1,200 CT scans could be stored on one CD-R. If one were showing a full abdominal CT study with 50–100 images per stack, one would be limited to 12–24 image stacks if he or she wanted to fit the entire presentation onto one CD. This limitation would be overcome if writable DVD (digital video disk) with a capacity of 5 Gbytes became a more common standard or if compressed images were used.
Patient confidentiality must be maintained. DICOM headers contain patient information, but the current implementation of DICOM for PowerPoint removes the patient name from the DICOM header. In some cases, the patient identifier is on the image itself. This is common, for example, with ultrasonographic images. It is possible to change the magnification and cropping of an image during a presentation and inadvertently display the patient information. Care must be taken to avoid this misstep by either not adjusting the magnification or cropping of the image during the presentation or by using only source images from which the patient’s name has been removed.
There are a large variety of DICOM image formats, and not all of these formats are supported by the current implementation. Most 12- and 16-bit monochrome images as well as a few 24-bit color images have been tested, but multiframe images and compressed DICOM images are not supported. In the current implementation of DICOM for PowerPoint, there is no smoothing of the image during magnification, nor is there a cine loop function.
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Windows versus Macintosh Operating Systems
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The lack of support for the Apple Macintosh platform (Apple Computer, Cupertino, Calif) is an inherent limitation of the implementation methodology used for the PowerPoint add-in described in this article. The code for reading DICOM formats is currently compiled and implemented for use with only the Microsoft Windows platform. In addition, the current version of Microsoft Office has no direct support for ActiveX controls for Macintosh computers. Although an implementation for the Macintosh operating system may be possible, a different approach would be required.
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Conclusion
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This article has demonstrated the feasibility of combining DICOM images into stacks as part of a PowerPoint presentation. This process can result in a more effective and higher-quality presentation of medical images.
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Footnotes
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Abbreviation: DICOM = Digital Imaging and Communications in Medicine
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References
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- Dreyer KJ. Using Microsoft PowerPoint for electronic presentations. RadioGraphics 2001; 21:1318-1321.[Free Full Text]
- Schreibman KL. Getting images into PowerPoint. AJR Am J Roentgenol 2001; 177:1271-1272.[Free Full Text]
- Corl FM, Garland MR, Lawler LP, Fishman EK. A five-step approach to digital image manipulation for the radiologist. RadioGraphics 2002; 22:981-992.[Abstract/Free Full Text]
- Taylor GA. Improving image contrast. AJR Am J Roentgenol 2003; 180:329-331.[Free Full Text]
- Taylor GA. Initial steps in image preparation. AJR Am J Roentgenol 2002; 179:1411-1413.[Free Full Text]
- Willing SJ. Getting images into PowerPoint. AJR Am J Roentgenol 2002; 179:533-534.[Free Full Text]
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Abstract
Introduction
