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Imaging at the Speed of Light
By Masha Zager
Sep 26, 2006, 15:57

The North Shore-LIJ Health System uses a high-speed fiber network to store and retrieve millions of medical images.

Not so long ago, if you had an X-ray or CT scan taken, the image was printed onto X-ray film, which was mounted on a light board for the radiologist to look at. After the radiologist finished with it, the film was stored away in a cavernous file room. But X-ray film, printing and storage are rapidly becoming things of the past. 

Today, hospitals increasingly use digital display and storage for their medical images. High-quality workstations are replacing light boards, and picture archiving and communication systems (PACS) are replacing vast file rooms.

Medical imaging is becoming digital largely for the reasons you would expect: the decreasing cost of computers, disk storage and networking. But there are other reasons, too. One is that digital systems can take advantage of new software that helps physicians analyze medical images – for example, by pointing out spots that might be tumors or by measuring calcium in the coronary arteries. Another reason is that the images have become too cumbersome to handle manually. An MRI or CT scan taken with advanced equipment can create hundreds of images in a single breath hold, more than the light board can display.

For any hospital, switching from film-based imaging to PACS is a major project. For a large hospital system, installing enterprisewide PACS is an undertaking of enormous proportions.
 

Centralizing the Image Archive

The North Shore-LIJ Health System, headquartered in Great Neck, New York, is in the midst of rolling out a PACS based on GE Healthcare’s Centricity system. North Shore-LIJ consists of 15 hospitals and dozens of freestanding facilities such as hospice and home care services, a major medical research institute and specialized clinics.

Until now, each of the facilities that performed medical imaging had its own system for storing the images, whether film-based or digital. When patients were treated at more than one facility, or when a physician at one facility needed to review images that had been taken at another facility, sending the images digitally was difficult and time-consuming at best, and sometimes impossible. Image files, which can be as large as 2 Gb, could take up to 10 minutes to retrieve.

The new PACS that North Shore-LIJ is installing will centralize the medical image archive for the entire health care system. Images created anywhere in the system can easily be retrieved anywhere else. All images will be stored in dual data centers, with full redundancy, so that they are always available.
 

Bringing the Network up to Speed

To support the new system, North Shore-LIJ had to upgrade its data network. It had been leasing a fiber ATM network from Optimum Lightpath, a division of Cablevision that provides business communications network services. The existing ATM network was solid, but it wasn’t flexible or scalable, according to Kevin Curran, Optimum Lightpath’s senior vice president for marketing and product management. North Shore-LIJ made the decision to switch to Optimum Lightpath’s carrier-grade Metro Ethernet system.

Adding more fiber and upgrading to Ethernet increased the network speed by roughly 20 times. The three core locations now have 10 Gbps, while the smaller facilities, some of which are still being upgraded, will have between 50 and 150 Mbps. The health care system can count on the new network meeting its needs for the foreseeable future. The three core locations can increase bandwidths up to 10 Gbps “with a phone call,” says Curran, and the others can increase up to 1 Gbps. Service increases can be provisioned remotely, without without sending technicians to the site.

The Ethernet network should also reduce maintenance costs for the health care system. It eliminates expensive router interfaces; with less equipment, there are also fewer points of failure, and fewer technicians will be needed to monitor and maintain the network. Optimum Lightpath is required to meet strict service level agreements specifying uptime (which is expected to be close to 100 percent), latency, jitter and packet loss.

Improving Patient Care

Images that once took 10 minutes to send digitally, or had to be sent by messenger, will be available in seconds.

The enterprisewide PACS running on the new network will improve patient care by making images more accessible. Images that took 10 minutes to send digitally, or that had to be sent by messenger, will now be available in seconds – allowing radiologists and cardiologists to make better use of their time, and to respond more quickly to requests for consultations.

There are other benefits, too. Enterprisewide PACS makes it easy to retrieve earlier images of the same patient and compare them to the current study, giving the physician a clearer idea of how a disease is progressing over time. And if a diagnosis is in doubt, the physician can easily retrieve images of other patients who were diagnosed with the suspected condition and use them for reference purposes.

Because the network also provides access to the Internet, images can even be sent over a virtual private network (VPN) to physicians at their private offices or home offices. The images sent over the VPN, which is slower than the Metro Ethernet network, are of somewhat less than “diagnostic quality” but are still adequate for physician use – for example, to help the referring physician understand the radiologist’s report.

While the PACS system is expected to account for between 60 and 80 percent of its traffic, the new network will also have plenty of bandwidth for other applications, according to John Bosco, North Shore-LIJ’s vice president and CTO. For example, the health care system is rolling out an enterprisewide electronic medical records system that will allow sharing of patient data across facilities. Electronic medical records are considered critical to reducing medical errors, improving patient safety and controlling health care costs.

The high-speed network also supports video, an important and growing application. North Shore-LIJ has its own production studio where training videos are produced, and these videos are available to doctors throughout the system. Videoconferencing is also becoming more important, as physicians increasingly hold video meetings both within and beyond the health care system. And as new applications come along, the system will be ready for them. “We expect the network to facilitate traffic shared by physicians all over the health system,” Bosco says.