Academia experiments with 3D stack viewing software

September 29, 2004

With the RSNA meeting just around the corner, luminaries are shifting their attention from handling the hundreds of images generated in a CT or MR exam to handling the ones they pick out to prove their cases in Chicago. The problem is all the more frustrating when physicians are aware that what can be done with images by way of a PACS cannot be done when using software such as Microsoft PowerPoint.

With the RSNA meeting just around the corner, luminaries are shifting their attention from handling the hundreds of images generated in a CT or MR exam to handling the ones they pick out to prove their cases in Chicago. The problem is all the more frustrating when physicians are aware that what can be done with images by way of a PACS cannot be done when using software such as Microsoft PowerPoint.

Tackling the challenge, researchers at the University of Michigan and Yale University have developed a tool that allows presenters to manipulate image stacks just as they would using a PACS workstation. Their solution, called StackViewer, offers radiologists the ability to interact with images the way they do in clinical practice, allowing them to easily and interactively display stacks of images in PowerPoint presentations, according to StackViewer designer Dr. Benoit Desjardins of the University of Michigan radiology department.

Before StackViewer, presenters had no way to manipulate image stacks, because the tools in use were created as ActiveX controls, with a number of inherent limitations, he said. The tools had not been developed to save images in a stack within the PowerPoint file itself. Thus, moving a presentation file to a different computer required moving a directory of image files along with it.

ActiveX controls have to be installed on a computer before they run. While this is relatively simple, it nevertheless requires another step that can hinder transfer and distribution of presentations. And, ActiveX controls do not run on Mac OS X.

StackViewer is programmed in Microsoft Visual Basic for Applications, the embedded macro language for PowerPoint. When StackViewer components are added to a presentation, embedded objects and commands are created within the PowerPoint presentation file. This allows stacks to be viewed on another computer without installing any new software, according to the StackViewer Web site created by Desjardins.

Images can be added to a stack in any standard image format supported by PowerPoint. The stacked images are saved seamlessly within the presentation file.

"The real beauty of our tool is that all the code to interact with the stacks of images is integrated in the PowerPoint presentation," Desjardins said.

StackViewer allows stacks of 2D images to be displayed interactively on Windows-based or Mac OS X computers without compromising portability or compatibility, he said. When radiologists run their PowerPoint presentations, they can interact with the stack in the same way they do on most PACS.