Dr. Mendelson is a Radiologist in the Department of
Radiology at The Mount Sinai School of Medicine, New York, NY. Portions
of this work have been presented at the following meetings:
- Mendelson DS. Image sharing: Current status, IHE and the RSNA/NIBIB
image sharing project. RSNA annual meeting 2010, Chicago, IL. Dec.1,
- Mendelson DS. IHE: Interoperability: Enabling patient control. IHE Connectathon Conference, Chicago IL. Jan. 18, 2011.
- Mendelson DS. Image sharing 2011 update. American Roentgen Ray Society Annual Meeting. Chicago, IL. May 2, 2011.
- Mendelson DS. Panel discussion: Meaningful use for radiology: A
vendor perspective. The Society for Imaging Informatics in Medicine
Annual Meeting. Washington, DC. June 2, 2011.
- Mendelson DS. Image sharing 2011 update. The Society for Imaging
Informatics in Medicine Annual Meeting. Washington, DC. June 2, 2011.
There are many good reasons for sharing imaging exams.1
For radiologists, a previous study is highly valuable for comparison
with a more recent study in which an apparently new imaging abnormality
is identified. Prior comparison exams also improve the quality of
interpretation and expedite clinical care. In addition, given the
continuing growth in healthcare expenditures, ready access to a previous
comparison study may avert the need for a more expensive or invasive
procedure to work up a current finding. For instance, a pulmonary nodule
that remains unchanged through 2 or 3 years of comparison studies can
be declared stable and nonaggressive, rather than being investigated
with CT or biopsy without those studies. Prior studies also help avoid
placing additional radiation burden on the individual patient and the
Patients are mobile; they often receive
healthcare services at multiple sites, and their images need to move
with them. They also often see a variety of specialists or seek second
opinions from other radiologists. Many patients, in addition, enroll in
clinical trials that require them to submit their imaging exams. Indeed,
the need for access to patients’ diagnostic imaging studies continues
to expand and requires an easy and secure mechanism to permit this
The first transition: Film to CD
film was the medium that physicians used to share exams with each
other. It served its purpose, but it was expensive, clumsy, and
inefficient. As a community, we all thought the compact disc (CD) was
the ideal solution.3,4 Cheap, portable, and able to hold
thousands of images and multiple exams, the CD certainly was an
improvement. But CDs also have problems: Many vendors employ proprietary
formats that cannot be opened on standard DICOM viewers; in many cases,
standards have not been followed. Also, many CDs include a viewer, but
viewers differ in significant ways and often are not intuitive to new
users or to those who use them only occasionally. In a clinical
practice, there just isn’t time to learn how to navigate each viewer. In
many offices, workstations are “locked down;” that is, as a security
measure, they won’t run external programs, including DICOM viewers.
Discs can also be defective and unreadable.
Occasionally, even the wrong patient is included on a disc. Lastly, the
entire process of opening a disc can be quite time consuming.
Make no mistake; despite their deficiencies, CDs represent a significant advance with regard to image sharing.3,4 Current data demonstrate that the quality of care improves when historical exams are easily available on CD.4
The CD is likely to remain with us for some time, and we must leverage
solutions that refine the workflow around the CD, making it an effective
means to share data while we transition to the next era—that of cloud
Extending the network: First steps onto the internetNetwork-based sharing
Once picture archive and
communication systems (PACS) and radiology information systems (RIS)
became commonplace, the next step was to move the images and reports
over networks, outside the radiology department and directly into the
hands of the clinical staff. As enterprises, in parallel with these
radiology developments, extended their internal networks, this became a
fairly straightforward task. Within the firewall, images were exposed on
local workstations through PACS client applications or Web viewers.
Clinicians soon wanted to be able to view exams in their offices, but
outside the firewall. Virtual Private Network (VPN) solutions have
emerged over the last few years, which provide credentialed physicians
with this access. The key phrase here is “credentialed physicians;” this
solution works well for physicians who are members of a system, but it
breaks down for those who are part of a separate organization.
patients, being extremely mobile, often visit providers who are members
of disparate healthcare systems, which don’t all have access to the
same VPN solutions. Yet it is highly desirable to provide image access
safely and securely with patient consent. How do we extend the network
outside of the local firewall?
Off to the clouds
share data over the Internet every day. Photographs and movies are now
instantly available wherever we are. We radiologists can move medical
images in the same way, albeit with appropriate security and privacy
measures. As bandwidth increases, the constraints on transferring large
imaging data files diminish. Medical enterprises have turned to the
vendor community for solutions; and the vendors have responded.
Cloud-based computing has been well described in many places.3,5,6 Both storage and image postprocessing can be outsourced from the local enterprise.5
Dr. Rasu Shrestha, the Medical Director of Interoperability &
Division Chief of Radiology Informatics, The University of Pittsburgh
Medical Center (UPMC), has provided an excellent summary of its
applications for an article in Applied Radiology.6
Basically, the sharing and exchanging of images through the Internet and
cloud-based services adhere to 2 overarching paradigms. The first is to
provide a set of services in the cloud that move images between sites
on demand. This methodology is often employed to manage point-to-point
transfers. The second method includes archiving the healthcare data,
including images, in the cloud so that the original source needs to send
the images into the cloud just once. All subsequent sharing takes place
from the cloud archive. This latter solution is the one generally
employed in Health Information
Exchanges (HIE) (Figure 1).
Several business goals may be achieved from these solutions.7
Cloud-based storage might initially be purchased as a data recovery and
business continuity solution. However, once the imaging data and
reports are present in the cloud, an additional set of services can be
added, employing the same archive, to share images. Another growing case
is for expanding a multi-institutional enterprise to employ a cloud
archive not only as a business continuity solution but also as an
integration point so that the multiple sites, with disparate PACS
systems and archives, can share images. Primary PACS services in the
cloud have arisen to provide small organizations with an economically
feasible solution when the outright purchase of a PACS system is
perceived as impractical or too costly. Economics and efficiency are the
main drivers toward cloud computing solutions.
solutions are limited in that they enable sharing through the cloud, but
only within a given enterprise. Easy and secure exchange of healthcare
data is a focus of Meaningful Use, a part of the American Recovery and
Reinvestment Act of 2009. Image-enabled HIEs are a next step in crossing
the boundaries of single enterprise data sharing. Many prototype HIEs
exist, and some enable the exchange of images. Many are built on
proprietary solutions and hence do not easily extend beyond the members
of the exchange. It is highly desirable that HIEs be built on a set of
commonly accepted standards so that technology does not represent a
hurdle to participation.
Integrating the Healthcare Enterprise
(IHE) provides just the answer to this latter issue. IHE profiles
describe standards-based interoperability; they employ common standards
and detail how to implement these standards in a fashion that is easily
duplicated and extended. A specific set of IHE profiles known as
Cross-Enterprise Document Sharing (XDS)8 describes how
independent enterprises can share medical images and other data. This
solution, which is increasingly being embraced internationally because
it provides for a standard, well-accepted means to build an HIE, is also
beginning to gain traction in the United States.
All of the above
solutions focus on sharing at the enterprise level. But a group of
radiologists working through the RSNA asked a different question: Could
image sharing be accomplished through Personal Health Records (PHR)
under the control of the consumer?
With support from the
National Institute of Biomedical Imaging and Bioengineering (NIBIB), a
pilot study is being designed to help answer this question. Five
academic sites—The Mayo Clinic, Mount Sinai Medical Center, the
University of Chicago, the University of California San Francisco, and
the University of Maryland —will enable their patients to transfer their
images to a PHR. From there, patients will have direct access to their
imaging exams and reports. The patients can then, on the spur of the
moment, sign into their PHR, launch a web viewer, and view their images
(Figure 2). As an alternative, a patient can email a link to a provider
that will enable the provider to look at the images on the web or
download them to a local workstation. This is built upon IHE-defined
profiles—again, commonly accepted standards with a strong patient
security and confidentiality model. This pilot is just being deployed as
this article goes to press.
Technical details of the RSNA/NIBIB project
are 3 main components to the RSNA/NIBIB pilot project: an edge server
(Figure 3), an imaging clearinghouse, and the image-enabled PHR. There
is an edge device at each radiology department. The patient is
registered on this device, which then waits for a message from the RIS
indicating that a finalized report has been issued. The edge device then
queries the PACS and packages the imaging exam and report. The
“package” is then encrypted and sent to the “clearinghouse.” The package
waits in the clearinghouse for the patient to request the exam from his
or her PHR. When the appropriate authentication is provided, the
patient can move the images and report into the PHR, where it is
de-encrypted. The PHRs permit patients to view their images, read their
reports, and distribute copies of each to their providers. Consumer
control of their own images and a commitment to standards via IHE
profiles are the governing factors. We hope this bootstraps image
sharing across the nation.
What are the potential limitations of
such a system? We believe that this solution will be highly desirable to
many patients, but not all. It presumes one is comfortable using the
Internet and with exchanging private information over the Web.
Individuals capable of conducting banking or shopping on the Web should
be able to participate. Those who are not facile with such technology
will not be good candidates for this solution unless they employ
In addition, there are issues with regard to trust in
one’s privacy, security, and confidentiality on any Web-based service.
Many consumers have concerns about these issues and will not embrace
this solution at this juncture. We have devoted significant resources to
ensuring a robust solution to these issues; nevertheless, some will
wish to observe for a while to gain confidence that this service cannot
The operational costs of this system, similar to
HIEs, are not fully understood. The cost of infrastructure is fairly
straightforward, but the cost of each transaction will depend on
multiple factors. We hope to use data from this pilot project to build a
series of economic models that explore the feasibility of obtaining
financial support from patients, payers, radiology departments,
healthcare enterprises, or a combination of these stakeholders.
this service must be easy to use, have high availability, and excellent
performance. We have built the application and put in place an
infrastructure to attain these goals. We must validate them in the real
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- Prevedello LM, Sodickson AD, Andriole KP, Khorasani R. IT tools will
be critical in helping reduce radiation exposure from medical imaging.
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- Mendelson DS, Bak PRG, Menschik E, Siegel E. Informatics in radiology: Image exchange: IHE and the evolution of image sharing. Radiographics. 2008;28:1817-1833. Epub 2008 Sept 4.
- Sodickson A, Opraseuth J, Ledbetter S. Outside imaging in emergency
department transfer patients: CD import reduces rates of subsequent
imaging utilization. Radiology. 2011;260:408-413. Epub 2011 Apr 19.
- Langer SG. Challenges for data storage in medical imaging research. J Digit Imaging. 2011;24:203-207.
- Shrestha RB. Imaging on the cloud. Applied Radiology. 2011;40:8-12.
- Langer S. Issues surrounding PACS archiving to external third-party DICOM archives. J Digit Imaging. 2009; 22:48-52.
- Integrating the Healthcare Enterprise: IHE IT Infrastructure
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Framework. Accessed July 27, 2011.