is the Director of the Radiology Informatics Laboratory at the
Medical College of Wisconsin, Milwaukee, WI.
What does it take today to have a successful enterprise-wide
picture archiving and communication system (PACS) encompassing the
entire institution? While many radiology departments are enjoying
the fruits of a filmless workplace, few institutions have been able
to shut down their film processor operations to the rest of the
hospital, thereby achieving the true cost effectiveness of PACS.
All PACS vendors claim that they have the right stuff to wean the
hospital from film, but do they really? And do you and your
institution have the right stuff to implement the change?
Finding the right recipe for PACS can be a daunting task. The
job is one part technology assessment, one part change management,
one part vendor management, and at least three parts understanding
your own environment. At the Medical College of Wisconsin, we have
distilled the essence of a successful PACS implementation down to
four critical components: (1) staffing, (2) infrastructure, (3)
integration, and (4) provision of a powerful common user interface
across the enterprise.
It takes a team
PACS is an information system, not an imaging modality.
Hospitals that treat PACS as a modality will suffer from inadequate
support, training, and from a lack of understanding of how
implementing PACS will affect their workflow. A PACS creates major
changes in how images are managed. Vendors cannot restructure your
organization to accommodate these changes; the restructuring has to
be done by a competent internal team. This team must understand the
technical, business, and user aspects of the changes brought about
by PACS. Many of the often-overlooked project requirements are
business related, such as how to sell PACS to the enterprise and
how to get upper management to buy in to the PACS vision.
A real technical challenge for the PACS team is in understanding
the concept of PACS as a mission-critical system. Most other major
information systems within the hospital have a proxy service
available in the event of downtime. For example, a physician can
always call the lab to get patient results if the information
system is down. But in the case of PACS, there is no way to
describe how an image looks over the phone to a surgeon. To instill
a sense of security for the PACS users at the University of
Pittsburgh, a "drop what you are doing," 90-second on-site response
time was implemented for all critical areas such as the emergency
room, intensive care unit, and radiology department. Dr. Paul
director of informatics, stated at the PACS 2002 conference in San
Antonio, "Our response team members wear white coats and act as
PACS consultants. They are more than just help-desk support. They
are part of the solution and need to understand how and where PACS
is being used."
To hire a PACS team you might need to think outside the box. Do
not confine your manpower search merely within the medical
environment; advertise in places where you can tap into qualified
information technology (IT) professionals. Acquiring talented IT
personnel and teaching them DICOM and PACS can be easier than
trying to find a qualified PACS expert. Look for individuals with
good project management, communication, and systems administration
A powerful user interface for the enterprise
Supporting proprietary workstations throughout the hospital is a
challenge for any PACS team. Not only does geography slow down the
response time, but maintaining workstations and providing periodic
application and system upgrades is also a real resource drain for
the team. Using a Web-based, or thin-client, distribution mechanism
alleviates many of the problems. A web-client software interface
can be distributed automatically to any workstation within the
hospital, as long as the receiving computer meets the technical
The Web is a great distribution mechanism, but the user
interface has to be just as powerful, intuitive, and responsive as
the clinical and diagnostic workstations. Also, many physicians
need advanced navigation and visualization tools, not just the
radiologists. A trend among PACS vendors is to provide a common
user interface for radiologists and referring physicians. This
approach simplifies training and support, and keeps referring
physicians from feeling like second-class citizens.
In implementing an enterprise PACS, one challenge is to predict
how many workstations will be needed. A good exercise is to count
the number of light boxes in the facility. Dr. Steve Horii
(personal communication, 1/2002) performed this experiment while he
was at the New York University Medical Center. Before he gave up
counting, he exceeded 1,000 light boxes in just the first three
floors of the 18-story building. To believe that a few dozen
dedicated workstations will replace all those light boxes is just
PACS is not an island unto itself. The buzz at the 2001 RSNA
meeting was about PACS and the integration with the radiology
information system (RIS). This reflects the realization that PACS
is not about moving images from point A to point B, but about
improving the productivity and efficiency of the department and the
institution. Combining a PACS and a RIS can be accomplished through
a proprietary interface, but will be more flexible for future
changes if it is done with an open architecture and industry
standards. The open standard initiative leading this integration is
the Integrating the Healthcare Enterprise (IHE) movement
(www.rsna.org/ihe). PACS/RIS integration should be part of any
request for PACS proposal. The IHE focuses on the integration of
RIS and PACS and reinforces core industry standards such as HL7 and
DICOM. "Radiology is leading the charge in workflow integration for
the entire healthcare with IHE" stated Jay Gaeta (personal
communication, 3/2002), a technical and planning committee member
of the IHE.
Manually synchronizing databases between the hospital
information system (HIS), RIS, and PACS is an error-prone and
time-consuming task. IHE outlines how to reconcile patient
information corrections among the three databases automatically.
presented a paper at SPIE this year that collected issue statistics
for the year 2000. He determined that >80% of the radiology
workflow problems encountered at the University of CaliforniaDavis
were solvable under the framework of the IHE.
Another trend is HIS/PACS integration. Physicians who just want
the report and a few key images shouldn't necessarily need to learn
PACS, but should be able to get the images as a transparent layer
through the HIS. Additionally, HIS/PACS integration saves a lot of
user-account duplication and eliminates the need to train the
entire hospital to use the PACS software. Having the entire patient
record at one's fingertips has been the goal for many years; it is
now eminently possible.
What makes PACS possible is that it is no longer an engineering
novelty. PACS relies on the computer networking, storage,
processing, and display industries. These major industries have
caught up with the technology requirements for PACS, which is now
becoming a coat-tail industry. Radiology can now enjoy the cost
savings of off-the-shelf commercial hardware.
This is important because performance is important for everyone,
not just the radiologist. Two important new trends are to put
everything on an online redundant array of inexpensive disks
(RAID), and to upgrade the backbone of the hospital network to
gigabit Ethernet. Physicians are not known for their patience, and
forcing them to stare at an hourglass while the system fetches the
images from a deep archive will not win many converts.
PACS is such a storage-demanding application that it was
actually driving the storage industry between 1988 and 1993.
There are now several advantages to putting all images online and
keeping them there. First, this option has become very cost
effective, with storage capacity doubling at no differential cost
every 14 months. This growth rate even exceeds Moore's law (Gordon
Moore, co-founder of Intel, stated in 1965 that the number of
transistors on a microchip will double every 18 months, effectively
doubling the processing power of computers. The ability to move
that data on the network and store that data on a hard drive has
also matched and even exceeded Moore's prediction for the past 35
years.) As an example, large hospitals generate approximately 10
terabytes of uncompressed data per year. That amount of data
storage would have cost $10 million for hard drives alone 8 years
ago. Today the cost is under $0.5 million.
Second, online storage offers instant access to the entire
archive. Third, system administration and architectural complexity
is reduced by getting rid of complicated prefetching, or purging
and fetching on the RAID back and forth to the deep archive, which
slows the RAID's primary function of getting images quickly to the
desktop. Lastly, migration from one physical media format to
another is avoided.
PACS is going mainstream as a cost-effective film alternative.
This is due to the highly accelerated pace of the computer industry
as well as the fact that the PACS industry has had 14 years to
develop standards and stable solutions that can now solve the
problems of image management for radiology and throughout the
enterprise. The challenge is really upon the IT and radio-logy
leadership of the hospital to understand and incorporate this
technology into their environment.