Virginia Commonwealth University
Understanding the Human Heart
“I was at Stanford University at a meeting and our technologists called me,” John Grizzard, assistant professor of radiology at Virginia Commonwealth University (VCU), recalls. “They were scanning a patient and suspected that she had an abnormality on the right side of her heart. They had done an MRI series, and the physician covering me wasn’t comfortable with giving an opinion on it. They asked me to take a look.”
Grizzard, who is also section chief of non-invasive cardiovascular imaging at the VCU Medical Center, fired up his PowerBook, opened a browser, and logged on through the VCU firewall to his department’s WebPAX server. In seconds the entire Picture Archive Communication System (PACS) study opened up on his screen in the browser — rows of animated magnetic resonance imaging (MRI) images of the patient’s heart, beating at its actual heart rate. Grizzard suggested capturing additional image sequences, and reviewed those as well. He finished by adding his diagnostic impression to the images and emailed them to the referring physician.
“The beauty and the difficulty inherent in cardiac imaging is that you need to see the heart move. And you must see it moving in real time — or in a rhythm that approximates the patient’s heart rate.”
“I was able to give them my opinion in real time,” says Grizzard. “It was very gratifying to be able to do that.”
Grizzard’s diagnosis of an aggressive primary cardiac tumor was confirmed by a biopsy, so this case did not have a happy ending. But his ability to call up minutes-old motion studies of a patient’s heart three time zones away demonstrated the power of WebPAX, a DICOM-compliant PACS that runs on Apple’s Xserve and Xserve RAID hardware and provides HIPAA-compliant access to medical images from any Mac or PC via a standard web browser.
The Beating Heart
“The beauty and the difficulty inherent in cardiac imaging is that you need to see the heart move,” says Grizzard. “And you must see it moving in real time — or in a rhythm that approximates the patient’s heart rate.”
To complete that wish list, radiologists prefer to see a heart in motion from several angles at the same time on the same computer screen. WebPAX has made this possible for the first time.
Medical scanners generate images in industry-standard DICOM format. The images are typically archived using a PACS sold by the scanner manufacturer. A common PACS-based image viewing setup, which requires software licensing from the manufacturer, includes two side-by-side vertically oriented monitors. Each monitor displays four images. Clicking on one of the images starts a looped series of scanned images. It is not considered a user-friendly system.
“It’s painful and cumbersome to try to convert still-frame scans into a real-time motion series,” says Grizzard. “You can set the frame rate at any speed you want, but you have no way to determine the patient’s actual heart rate. In any case, most PACS graphics processors can only animate one image series at a time.”
Fast, Simple, Cost-Effective PACS Workflow
Solving these PACS workflow problems for cardiologists is the mission of HeartIT, the developer of the Mac-based WebPAX platform. The purpose of WebPAX is to give physicians fast, flexible access to cardiac images at substantially reduced cost.
The basic WebPAX solution includes two Xserves and an Xserve RAID. One Xserve node (the Master) is an Apache web server that makes PACS images accessible through a browser on any computer anywhere. The other Xserve node (the Converter) converts DICOM data to GIF images that are stored on the Xserve RAID along with their HTML web pages and the raw DICOM images. An ingenious WebPAX software routine uses time-stamp information in the header of each DICOM image to display multiple real-time motion images of a patient’s heart, beating in unison at the patient’s native heart rate, on a single screen.
The PACS solutions offered by diagnostic equipment vendors typically include very expensive workstations and require a client software license fee for every PC on which PACS images can be viewed. The cost of client licenses limits the number of PCs on which hospitals can install the software, so PACS viewing locations for physicians are few and are limited to the local network.
WebPAX, on the other hand, enables any healthcare professional with access privileges to view PACS images from any computer with a web browser, anywhere in the world. The cost of proprietary software licenses is eliminated, and so are the hardware, staffing, and other IT administrative costs required for maintaining and upgrading licensed workstations to the standards required by the software. Specialists and referring physicians can easily access images from their offices, homes, hotel rooms, or wi-fi hot spots.
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