is the Clinical Section Head of Imaging Informatics, Geisinger
Health System, Danville, PA. He is also a member of the editorial
board of this journal.
Descended from monkeys? My dear, let us hope it isn't
true! But if it is, let us pray it doesn't become widely
Quote attributed to the wife of the Bishop of Worchester
The picture archiving and communication system (PACS)
workstation has been an object of radiologist desire and derision
for the past 20 years. Softcopy viewing functionality has developed
synergistically and in parallel with mega-slice computed tomography
(CT) and multiseries magnetic resonance (MR). Along with technology
advances, radiologist training and experience have necessarily
evolved as well, with the implementations of tile mode, to stack
mode, to 3-dimensional, and 4-dimensional image interpretation.
Increasingly complex image analysis capabilities are raising the
bar for even rudimentary workstation requirements. Moreover, the
need for interoperability with a multitude of other systems is
becoming pervasive. Vendors of PACS are well aware of these
challenges and are taking steps to meet them.
The PACS workstation evolved from 2 requirements-radiologists'
need to view an increasing number of anatomically related CT and MR
images, and the yearning for freedom from the geographic tyranny of
proximity to the film library. At the same time, computed
radiography technology for projection radiographs allowed softcopy
viewing of these images. Pre-existing digital modalities, such as
ultrasound and nuclear medicine, were naturally suited for PACS
viewing. Rudimentary workstations were developed initially for
off-site viewing to ease the burden of night call. Current
workstations retain some DNA from these PACS precursors. In-house,
many radiologists initially used a modality workstation to scroll
through CT data. This was marginally satisfactory, but more
functionality—both in image viewing and areas such as worklist
control and image display—was desperately needed.
Enter the full-function PACS workstation. These developed in an
era before the availability of the Windows platform. Early PACS
vendors often relied on UNIX software and were held hostage by
low-bandwidth networks. With these thick clients and the
limitations of transmission speed, complex routing algorithms were
developed to send image data sets to predefined workstations where
the appropriate radiologist subspecialists would be working.
, this workflow, born of necessity, had its limitations. If studies
that were not resident on the local hard drive were needed, an ad
hoc query of the database often took many minutes.
Second-generation PACS were able to utilize the then-novel
Windows technology as well as higher bandwidth for what many called
centralized PACS architecture
-a philosophy of any image, anywhere, anytime. Images were pulled
from a centralized server only when needed. This advancement
allowed a move toward thin-client workstations with more
server-side computation. Radiologists were released from the yoke
of having to sit at a prechosen workstation and were no longer at
the mercy of an overmatched network for ad hoc queries.
Later PACS vendors took the thin-client workstation concept even
further. Rather than upload 1 full case at a time, these
workstations worked on a just-in-time delivery principle in which
images and resolution were dependent on real-time user requests.
This ultra-thin-client architecture had high bandwidth requirements
and worked extremely well in a hospital environment. Challenges
arose when the increased demands of off-site reading, an
increasingly common workflow, became more pervasive.
Currently, most vendors are moving toward a hybrid environment
that combines the best features of distributed and centralized
architecture to accommodate all reading patterns. Newer vendors
have perhaps had an easier time of this, standing on the shoulders
of the early designers. Several of the original PACS vendors have
had more difficulty making these rapid changes because of the need
to accommodate legacy customers with backward compatibility.
In addition to architectural changes, the phenotype of the
workstation itself has also evolved. Early monitor configurations
emulated the 4-over-4 lightbox, assuming that radiologist reading
patterns would remain the same. The number of monitors decreased
rapidly in the early PACS years to 4 and then to 2 as users
realized that reading in softcopy was radically different from
(Almost all workstations now have a third monitor, sometimes of
lesser resolution, for text and other non-image-related
information.) Early investigators confirmed the 2-monitor
workstation as satisfactorily efficient,
but some radiologists are now returning to a greater number of
diagnostic monitors as studies and comparisons become more
Dr. Rubin Mezrich, University of Maryland, is fond of reminding
us that the
, a concept seemingly forgotten by some software designers. Dr.
Steve Hori, University of Pennsylvania, was perhaps one of the
first to introduce the concept of a single-point-of-contact (SPOC)
workstation that would accommodate all functions needed by the
radiologist. These 2 requirements are facing a moving target as more
is being asked of workstation functionality.
Today’s requirements, tomorrow’s technology
The current PACS workstation is functional and utilitarian, a
combination acceptable to many practicing radiologists. Images are
displayed in a reasonable length of time with personalized hanging
protocols. Image manipulation and annotation can be performed in a
marginally acceptable number of steps. Worklist functionality is
arguably robust enough for the average user. But there is great
potential to take the average PACS workstation to a much higher
level of functionality with some relatively minor
Current worklist functionality in many PACS accommodates only 2
states-read and unread-with studies dropping from the worklist as
soon as they are marked read. This, however, is a simplistic view
of quotidian workflow in the average radiology department. Many
cases are not ready to be read, yet should not remain on the
worklist. A study that needs a second opinion or one that needs
additional views should be moved temporarily to a separate folder
until these requirements are met. Likewise, there should be easy
functionality to copy a study to another folder, such as an
interesting case list or a teaching file. The folder concept was
introduced early in PACS development
and is now being expanded by most vendors to further improve
usability and functionality.
With the exponential increase in corporate acquisitions and the
consolidation of hospitals and imaging centers, many radiologists
are facing the daunting task of using multiple PACS and radiology
information systems in their daily image interpretation, moving
from workstation to workstation and interacting with multiple user
interfaces. A single worklist orchestrator is now within reach to
consolidate all workflow to a centralized worklist. Ultimately, all
of these images could be consolidated as well in DICOM format and
interpreted on a single viewer, obviating the need for a knowledge
of multiple user interfaces.
Hanging protocols, the ability to automatically arrange and
display images in the proper configuration and sequence,4
must improve as well. As the number and diversity of image series
become more pervasive, vendors are facing the challenge of
increasing the complexity of hanging protocols while at the same
time maintaining ease of creation by the user. A good example of
this is digital mammography, in which many users are finding that
the switch to softcopy reading is accompanied by a decrease in the
speed of interpretation.5
The development of reading protocols—an automated user-defined
sequence of hanging protocols—has helped but has not alleviated
this negative impact. Future hanging protocols must accommodate not
only conventional images but also advanced visualization
techniques. In fact, some radiologists are abandoning conventional
PACS to view images primarily on their advanced visualization
workstations. PACS vendors are taking steps to reverse this trend
by offering native advanced visualization features. They must also
begin to incorporate third-party volume image interpretation into
their own hanging protocols.
The graphic user interface (GUI), the feature used to manipulate
and annotate images, needs some streamlining in almost every
current PACS. Most workstation software now relies on some
combination of pulldown menu, icon click, or keyboard commands for
user input. Studies have shown that any time a radiologist’s eyes
move from the image it creates a distraction, which has the
potential for decreased diagnostic accuracy.
The future GUI must allow total image manipulation without visual
input. This can be accomplished to a great extent with alternate
mechanical user interface devices (such as the ShuttlePro, Contour
Design, Inc., Windham, NH) combined with software modifications
(Figure 1). An increasing number of radiologists are finding this
workflow useful in daily image interpretation.
Communication features are an integral part of PACS and should
be easily accessible at the workstation. These include not only the
creation of a conventional radiology report, but also real-time
bidirectional collaboration among radiologists and clinicians. With
more and more reports being sent and read using electronic means,
the multimedia report is becoming more popular. Such a report can
include annotated thumbnail images with hyperlinks to appropriate
text, voice recordings, links to online references, and other
advanced features that create a richer environment for information
exchange between the radiologist and the clinician.
The PACS workstation must accommodate these new features and allow
efficient creation of these reports by the radiologist. This will
be possible only by maximizing interoperability between the
reporting and the image viewing software. Radiologists also have an
increasing need for rapid and contextual data retrieval from the
electronic medical record. It is no longer sufficient to simply
have access to all of the laboratory values for a particular
patient. The software should have the functional intelligence to
filter this data depending on the situation. For example, if a
radiologist is working in the protocol page for a CT scan, the
system should have the ability to display the latest renal function
Until recently, PACS vendors’ focus has been on consolidating
the features discussed above and improving usability and efficiency
at the workstation level. Like building a home, these are
structural and required features, such as roofing and siding.
Network capability, like wiring and plumbing, is also an absolute
requirement that should function in the background without
visibility. Such is the current status of PACS workstation
functionality. We have built our homes with relatively robust
infrastructure and are secure from the elements. We must now look
toward improving our surroundings by accessorizing this environment
with third-party functionality. PACS vendors have always faced the
dilemma of which features to provide with native software versus
utilization of third-party specialty vendors. Many radiologists
prefer highly functional nuclear medicine, ultrasound, and advanced
visualization software to those available on their own PACS
workstations. Digital mammography is an extreme example in which,
until recently, a stand-alone specialty workstation supplied by the
mammography vendor was an absolute requirement for digital
interpretation. These divisions are becoming blurred as vendors
begin to include not only native specialty interpretation software
within PACS but also increasingly seamless integration with
third-party vendors. In addition, some vendors are partnering with
third-party companies to allow users to create highly customized
worklists based on their individual workflow. Third-party data
search engines and decision-support software is also being
integrated into PACS. These advances will benefit radiologists as
we continue to squeeze out every drop of efficiency in an attempt
to accommodate an ever-expanding number of images.
Scientists and engineers at Intel are excitedly anticipating the
Era of Tera. New hardware and software developments will allow
terabyte per second bandwidth and teraflop per second performance.
The implications of these advancements on end-user functionality
are obvious. More robust computing power will allow faster
reconstruction for advanced visualization with the capability of
even thinner clients for enterprise distribution of volume image
rendering and manipulation.
The concept of pervasive computing is also anticipated. This
will allow wireless access to powerful server technology anywhere
within the geographic confines of a healthcare facility. A
hand-held intuitive user-interface device will navigate images on
existing monitors or perhaps will project images onto a wall or
screen anywhere in the enterprise and beyond. This degree of
mobility, with automated biometric security, will allow all
healthcare providers instant access to images and data with minimal
The user interface, graphic and mechanical, will become more
critical as users have more access to images and data. Current PACS
software was designed around the already antiquated keyboard/mouse
combination. The marvelous mechanics of opposable thumbs, a
gargantuan genetic advantage shared by few other species, is being
sorely underutilized with such conventional hardware. The alternate
mechanical user-interface devices currently being used are an
improvement but are ultimately a retrofit to this arguably flawed
software. The innovative designers at Apple have taken a step in
the right direction with the iPod, an elegant design that
simultaneously marries conceptually new hardware and software.
Microsoft has progressed similarly with its Surface computer
interface, a completely smooth horizontal surface that responds to
touch and placement of other devices. This and the newer iPhone
interface might seem ideal for PACS use, but this may not be the
case. Our workflow requires our eyes to be riveted on the images
and not on the interface. Haptic feedback is still needed in any
combination of graphic and mechanical user interface for radiology;
however, the concept itself—that of combined and simultaneous
software and hardware design—should still be emulated within our own
With these hardware and software technology advances, it is
likely that radiologists will spend more time in image viewing and
less in other tasks. The frailty of our own bodies may very likely
become the limiting factor in maximizing efficiency. For some
time, researchers have been interested in minimizing the physical
and mental impact of the daily interpretation of thousands of
images—a situation in which the implications of an error could not
Like a baseball player at the end of a long season, the wear and
tear on our bodies and minds is taking its toll.11
Attention to such details as lighting, temperature control,
background noise, and proper body position will be an increasing
factor in workstation and reading room design.
As radiologists, we are struggling with ever-increasing demands
on our time and with a continuing need to master new
technologies that generate an astonishingly high number of images.
Rapid control and manipulation of these images without distraction
is vitally important. It is clear that a radiologist with 3 hands, 4
eyes, and 2 brains would be beneficial; however, it is unlikely
that the rate of biologic evolution will match that of our own
technology. Radiologists must remain knowledgeable in evaluating
new PACS workstations while customizing software and hardware
interfaces to best accommodate our individual workflow.
- Moise A, Atkins MS. Design requirements for radiology
J Digit Imaging
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- Bennett WF, Vaswani KK, Mendiola JA, Spigos DG. PACS
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J Digit Imaging
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- Reiner B, Siegel E, Hooper F, et al. Effect of screen monitor
number on radiologist productivity in the interpretation of
portable chest radiographs using a picture archiving and
J Digit Imaging
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- Andriole KP, Avrin DE, Yin L, et al. PACS databases and
enrichment of the folder manager concept.
J Digit Imaging
- Haygood TM, Whitman GJ, Atkinson EN, et al. Results of a
survey on digital screening mammography: Prevalence, efficiency,
and use of ancillary diagnostic aids.
J Am Coll Radiol
. 2008; 5:585-592.
- Atkins MS, Moise A, Rohling R. An application of eyegaze
tracking for designing radiologists’ workstations: Insights for
comparative visual search tasks.
ACM Trans Appl Percep
- Weiss DL, Siddiqui K, Scopelliti J. Radiologist assessment of
PACS user interface devices.
J Am Coll Radiol
- Reiner BI, Knight N, Siegel EL. Radiology reporting, past,
present, and future: The radiologist's perspective.
J Am Coll Radiol
- Siddiqui KM, Chia S, Knight N, Siegel EL. Design and
ergonomic considerations for the filmless environment.
J Am Coll Radiol
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- Harisinghani MG, Blake MA, Saksena M, et al. Importance and
effects of altered workplace ergonomics in modern radiology
- Springen K. The dangerous desk. Mouse-clicking isn't heavy
lifting, but it can cause injury. How to keep your job from