Ultrasound PACS: The Ultimate Solution

Whatever your choice - dedicated or multimodality ultrasound PACS - the technology continues to win user praise across medical specialties. All users agree: There's no better way to share ultrasound images, information and expertise than via PACS. And the view can only improve as more facilities look to the capabilities of 3D ultrasound to get more information by creating 2D slices without requiring increased examination time for patients.

Ultrasound PACS continues to impact care for pediatric, obstetric-gynecology and cardiac patients as technologists capture, share and archive images with ease. For children whose bodies scan easily, for ob-gyn patients who need monitoring and for cardiology patients whose arteries require a thorough but non-invasive means of viewing problems, ultrasound PACS captures the views and stores them online, nearline or offline - depending on caregivers' needs. The images and reports are literally at the sonographer's or radiologist's fingertips, for as long as needed.


At Mayo Clinic in Rochester, Minn., ultrasound PACS not only has improved efficiency, increased productivity and cut costs, it has allowed the patient itinerary to be shortened substantially, according to Bijoy Khandheria, M.D., director of cardiology and chairman of information technology. Carotid and vascular imaging stored on PACS has reduced transit time by eliminating the need to physically transport images from one point to another. Mayo performs 50,000 to 60,000 vascular studies per year and uses an ALI ultrasound PAC system. Images are shared among several group practices around the country and with the regional Mayo Health System.

"We have an MR and CT PAC system because the number of films generated at Mayo is too large to fit into a multimodality PAC system, so we have multiple PAC systems for different modalities, and overarching them is the radiology information management system," Khandheria says.

If you were to have an x-ray done and a CT of the carotid, the system knows that patient "A," for example, with identifier "A" has an ultrasound image on one system and other accompanying scans on a second or third system. "When I'm sitting at a desktop and want to pull those images, it would show up on a list and would [point] me to the ultrasound study, so it's a virtual multimodality PACS, not a single PACS."

The challenge of storing high frame rate, real-time images has been a reason that ultrasound PACS has lagged behind other modalities in managing images electronically. Cardiac ultrasound moves at 30 frames per second. For 3D ultrasound, the rate increases to 60 frames per second. "The challenges of storing high frame rates in real time are a little different from storing high-volume or high-density data that CT or MR generates," Khandheria says. "Ultrasound PACS is a little more difficult, and DICOM has been a little slower in the ultrasound field than it has in x-ray, CT and MR."

To retrieve real-time, 30-frames-per-second images, high bandwidth transmission media are needed. "Small Ethernet is good enough, but it's not really fast enough," Khandheria says. "You need faster transport media and faster pipes, so that's been a challenge. One requires 100 gigabyte Ethernet or ATM [Asynchronous Transfer Mode] networks to make this happen in real time. You need workstations that are fast as well, two or higher gigahertz chips." Workstations, such as the Barco monitors used at the University of Alabama at Birmingham Hospital, in conjunction with Siemens Acuson's KinetDx dedicated ultrasound PACS, provide views of the 20,000 studies performed per year at the hospital and clinic.

"The ultrasound workstation [has] dedicated monitors," says Felix Hester, RVT, RDMS, RT, radiology ultrasound supervisor. "The ultrasound images have 24-bit color, and most radiology PACS cannot support that type of color display…specific to ultrasound. Ultrasound needs the high resolution of gray scale imaging and the crispness that is needed to display color. That's what sets PACS monitors apart from the others." KinetDx has 380 megabytes of RAM. Image access is instantaneous. The hospital system has a fiber optic network, providing a hundred megabits per second.

"Being able to look at [dynamic] clips [as opposed to static shots] was one of our criteria at the time we set out to look at PACS," Hester says. The ability to view clips has enabled faster exams, increased throughput and increased accuracy of diagnoses by showing fetal heart motion and blood flow.


The University of Arkansas for Medical Sciences faced a dilemma when it realized its approach to ultrasound needed to change, but PACS was something not all decision-makers were ready to embrace. Film had a strong hold.

But a dedicated ultrasound PACS found its way into the hospital, transforming care delivery.

"It was becoming impossible for us to function without a PACS at the time we [bought] it [in 1996]," says Teresita Angtuaco, M.D., professor of radiology, obstetrics and gynecology and radiologic technology and director of the Division of Imaging at the University of Arkansas for Medical Sciences. "That's why, in spite of the hospital's inability to provide us with one, both the departments of obstetrics and gynecology and radiology decided to put together their own professional funds to buy the system."

Prior to the installation, the hospital was unable to connect electronically to any labor and delivery patient information outside the hospital, so the satellite clinics functioned as small, independent operations. "We had to have a physician present at every little operation during the time the examinations were done in order to be able to render an opinion on the studies, because all you [had were] films at that time."

The PACS enabled a connection whereby one physician can run two or three clinics at the same time, with the capability to watch the examinations while they're being done on the PACS. "We were able to open more clinic space because we were able to increase our throughput," Angtuaco says. "You don't have to develop films; you don't have to dictate reports any more….With the PACS [and] built-in reporter, they're able to almost do the report before the patient even leaves the department. It allowed us to do things that we were not able to do before [including linking satellite sites to view examinations in progress]."

In the future, a federal project will connect the University of Arkansas for Medical Sciences facility with small hospitals around the state. Through its PACS, the hospital will be available for remote consultation whenever patients in satellite sites require it. The goal is to add approximately five hospitals per year for the next five years to expand ultrasound service to small hospitals. "Eventually, we're going to have a lot of small hospitals attached to our PAC system without having one of us present there during the scanning period," Angtuaco says. "[The system will] allow access to patient care in hospitals in remote areas. You can train a local person to do the basic scan, and you can look at the images and decide whether or not the patient needs to be sent over to the main hospital three hours away. It's consulting, rendering an opinion over the phone, based on what you see in the images in front of you that have traveled by network."

The speed of the network remains a concern. Currently, the hospital has to go through T1 lines, or in some cases, ordinary telephone lines. So slowness of the network becomes an annoyance. Angtuaco says the ideal situation would be for the state to have a fiber optic network for the hospitals for quick access to images.

And as storage challenges increase - OB patients' records are retained for 21 years - readiness of retrieval becomes a concern as well. The hospital plans to pilot new software for storage and archiving from TeraMedica that will prioritize all examinations and direct the images to be stored online, offline or nearline, depending on the urgency of the case.

Angtuaco says it would have been ideal if at the time they bought their ultrasound PACS that they had the multimodality system. "McKesson did not have a multimodality system at that time anyway, so that never came into the equation," Angtuaco says. "But about two years later, our department switched to PACS, and trying to marry the two became a problem at first. Right now we're using our current PACS, which is a Canon system, as a backup to our ultrasound system."

Everything on their McKesson ultrasound PACS is stored on the Canon PAC system, except for video clips. The Canon system is being used as a redundant storage until a bigger archiving storage solution is implemented. To complicate matters, the ultrasound PACS runs on a Windows platform, but the Canon PACS is Unix-based.


At Children's Hospital in Chicago, the multimodality PACS that includes ultrasound has resulted in better connections between sites, increased efficiency and the predictable elimination of lost films. Children's and its affiliated hospital performed more than 13,000 ultrasound exams last year, averaging a 10 percent increase annually for the last three years. It has reduced the amount of time it takes to process the images by sending them directly to PACS. The radiologists have instantaneous access, so the interaction between the sonographer and the radiologist happens faster. The system reduced paperwork as well, because everything is online. It incorporates voice recognition for transcription of reports.

Their vision was that as a matter of practice, it is important for them to have access to all imaging and reports, thus the multimodality system. The bulk of ultrasound studies at Children's Hospital are renal scans, but examinations cover head to toe, including vascular imaging for blood clots, abdominal imaging for children exhibiting pain and extremity scans for masses or foreign bodies. Children's ultrasound PACS vendor is GE Medical Systems. The hospital also uses Siemens Sequoia and Philips HDI 5000 ultrasound technology.

"I think that the [inherent technological challenge in ultrasound] is why a lot of institutions have stuck with the mini-PACS solution as opposed to going directly into PACS," says Cindy Rigsby, M.D., division head of body imaging for the Department of Medical Imaging. "One of the biggest challenges is the way the information is sent out of the ultrasound machine and stored in pixels. Just getting the resolution to correlate with the resolution in the PACS took a lot of tweaking."

One of the most frustrating issues at Children's, because the images are stored in pixels, is that measurements taken in PACS cannot be stored. Every time you do a pixel measurement, you have to re-identify your calibration factor. To improve efficiency, Rigsby would like to do calibrations after the fact, rather than at the time of acquiring the image. "To do that, you would have to have the same calibration software as the PAC system, or something similar," Rigsby says.

Ultrasound's future will include three-dimensional capability, and children will be part of the picture. "Ultrasound is totally suited to their entire body and can penetrate these patients, so once that 3D technology becomes widely available and user friendly, that's what we're going to see most of all," Rigsby says.

The future likely will include obtaining a volume acquisition and getting some selected, additional 2D images created off the 3D volume to help interpreting physicians get more views. Although it will require more memory, it is theoretically possible to save 3D volumes.

Improving the clip storage is on many users' wish lists, too. Traditionally, in body imaging, they are actually reviewing still shots. "We could do more clip storing in a more efficient way," Rigsby says. "Today it's cumbersome and repeating the same cycle, so I think that's another segment that PACS vendors will continue to work on improving to support the ultrasound world. That will take ultrasound to the fourth dimension - time."