Global Teleradiology - An internet-based application for
optimization of health care delivery across domestic and
Arjun Kalyanpur, MD
CEO and Chief Radiologist, Teleradiology Solutions.
Senior IT Manager, Teleradiology Solutions.
Sanjay Saini, MD
William P. Timmie Professor and Chairman of Radiology
Emory University School of Medicine
Doctoral Candidate, University of Arizona
Teleradiology refers to the electronic transmission of radiological images, such as X-rays,
Computed Tomograms (CT’s), and Magnetic Resonance Images (MRI’s) across
geographical locations for the purposes of interpretation and consultation. The digital
radiological images are typically transmitted using standard telephone lines, satellite
connections, or wide area networks (WANs). Teleradiology is an empowering technology
and a facilitator for enhanced medical care. Teleradiology enables a single radiologist to
simultaneously provide services to several hospitals independent of their location and
also allows the exploitation of global time differences to provide emergency night
coverage by personnel in a different time zone working a day shift. Additionally, the
quality of care delivered by a wide awake, alert physician working a day shift is far
superior to that provided by a radiologist who is up all night. Subspecialty opinions
delivered to locations where the expertise is otherwise unavailable are an added benefit.
In this paper, we describe the current state-of-art in teleradiology, the benefits of the
clinical practice of teleradiology, and the technical, regulatory and security issues related
to teleradiology. We begin by providing a historical background describing the evolution
of global teleradiology.
2. Teleradiology: A Historical Background
Although the concept of Teleradiology was first tested and clinically utilized in the late
1950’s in Canada, the high cost of transmission and the variability in digital imaging
protocols limited the widespread adoption and application of teleradiology applications.
However, the rapid progress in digital communication technologies and the development
of efficient internet-based software for image transmission, storage and display in the
1990’s has significantly reduced the technical barriers to teleradiology adoption. In
addition to the above developments, the universal adoption of the DICOM standard, as
required by the ACR-NEMA (American College of Radiology and the National
Electronic manufacturers association) has enabled the wide spread adoption of
Today Teleradiology has become both global and online. The precedent for
globalization of teleradiology was set by the Information Technology services Industry
which has pioneered the concept of the Global Office where the work “follows the sun” -
i.e. divisions in different time zones connected over a WAN provide a 24-hour
workforce, with no individual having to work a night shift at any location. Extended to
teleradiology, this means that the interpreting radiologist for a given hospital can
potentially be located anywhere on the globe and day-night time differences can be
exploited to staff the ER night shift. Teleradiology Solutions has been among the first to
utilize this technology to influence patient care across the world. A paper published by
Kalyanpur et al., from Yale University showed that this was both technically and
clinically feasible .
In addition, several market-based factors such as staffing shortages, increase in
imaging volumes, new technology and insurance and regulatory changes have also
contributed to the growth and development of Teleradiology. We briefly describe these
Radiologist Staffing Shortage: A significant shortage of radiologists (estimated at
approximately 20%) became apparent in the US towards the turn of the millennium, with
a large cohort of senior radiologists retiring from practice and training programs not
having grown adequately to keep pace with the increased needs. In many other parts of
the world, a similar shortage of trained/skilled radiologists exists. As might be expected,
in a time of staffing shortages, it is the night shift in the community hospital that is
typically hit the hardest, although academic departments also stand to benefit from
having their off-hours/overflow work done remotely by faculty based offshore .
Increase in Imaging Volumes: The rapid evolution of faster imaging technologies such
as multislice CT, faster MRI scanners and sequences, coupled with an ageing population
in the US has led to a consistent per year increase in imaging volumes in recent years.
Increase in Trauma Imaging Utilization: The development of newer applications of
CT in the emergency setting has necessitated a large increase in 24 hour radiologist
coverage at hospital emergency rooms . In addition, the Health Care Financing
Administration (HCFA) has requires that, in order for the services to be billable,
overnight coverage for radiological services be provided by a fully trained and certified
radiologists, rather than residents/trainees . This has resulted in a large increase for
overnight radiologist services.
3. A Service Delivery Model for Teleradiology
Advances in information and communication technologies in the past decade have
enabled new extensions to teleradiology facilitating new models and avenues for
delivering radiological services. The foremost application of teleradiology is in the
emergency setting. In emergency situations, teleradiology facilitates a prompt response
by bringing the emergently performed images to the off-site radiologist that allows for
timely diagnosis and the timely administration of appropriate treatment.
Rural & Remote
Figure 1. A Service Delivery Model for Teleradiology
“Nighthawk” Services: Teleradiology within the US led to the development of the
nighthawk concept wherein a radiologist is able to simultaneously provide services to
multiple hospitals via teleradiology links to a central reading facility (often the
radiologist’s home). Thereby enabling a single radiologist to simultaneously staff the
night shift at multiple hospitals. The process is cost-effective to hospitals, as the need to
recruit night shift personnel is minimized.
Radiology to remote locations: Teleradiology also enables the provision of radiological
services to remote locations where the technical infrastructure for radiological scanning
exists, but a radiologist is not available on site.
Optimization of workflow: Teleradiology also increases the efficiency of a radiologist
by ensuring that he/she spends the most part of his/her time delivering quality care to the
maximum number of patients. This is achieved by bringing the images to the radiologist
rather than vice versa, thereby saving physician commuting time and increasing the range
and reach of the radiologists’ expertise. Within large radiologist groups servicing
multiple hospitals and imaging centers, teleradiology also permits the optimal distribution
of work based on need and the availability of radiologists.
Subspecialty consultations: Teleradiology enables the wider availability of subspeciality
consultations wherein images of a specific body region/modality need to be referred to
the radiologist with expertise in the interpretation of that type of study.
4. Technical Requirements for Teleradiology
The key components of a Teleradiology system include a picture archiving and
communications system (PACS), a radiology information system (RIS) and a reliable and
secure high-speed connectivity between the remote sites. These put together with
standards for imaging and systems/procedures for security and contingency practices
complete the technical aspects of Teleradiology. These are further discussed in the
4.1 Picture Archiving and Communications System
An efficient web-based PACS is the cornerstone of a clinical teleradiology practice.
PACS is the information system used for the acquisition, storage, communication,
archival, viewing and manipulation of radiologic images and related data. This definition
of PACS indicates that PACS is made up of several important components. These are:
Acquisition Devices: These could be modalities with digital output capabilities or
devices such as frame grabber and digitizers that convert the analog output from imaging
modalities to a digital format.
Storage: This includes short term as well as long-term archival solutions. This allows
radiologists to have easy access to relevant prior studies for comparison. Long-term
archives need not have instant accessibility and hence optical disks or tape drives could
be used for this purpose.
Communication: PACS requires high-speed connectivity to enable rapid transfer of
images to viewing workstations, over LAN and WAN (the latter is what constitutes
teleradiology). Transmission of images is based on protocols of imaging standards called
DICOM. Transmission of non-image data like text uses HL7 standards. More on DICOM
and HL7 will be discussed in later sections.
Software: Image viewing and manipulation software are most often an integral part of
PACS. Image viewers can be on a Diagnostic workstation, review workstation or could
be done utilizing a web-based module. Diagnostic workstations are high end systems
with high resolution flat panel displays while review workstations/ web viewers can be
standard desktop PCs.
Image Compression: Given the large file size of typical radiologic images, an important
feature required facilitating rapid image transfer and throughput in Teleradiology is
compression. Compression algorithms used may be industry standard like JPEG 2000 or
could be proprietary to the vendor. It has been noted that compression settings of up to
10:1 can be tolerated in clinical teleradiology without compromise or loss of clinically
relevant data, for review of CT images . In the case of plain radiographs, even higher
settings may be tolerated.
4.2 Radiological Information Systems
RIS is often a subsystem of Hospital Information System (HIS), but can be also be a
stand-alone entity and may or may not be connected to PACS and/or RIS. While PACS
mainly deals with images, RIS/ HIS deals with data associated with patient demography,
studies and reports. RIS is often what guides the workflow of a Teleradiology practice.
Though RIS was used as a report generation and distribution tool earlier, commercially
available RIS packages currently have integrated many features like voice recognition,
staff scheduling, work distribution, invoicing, etc. At Teleradiology Solutions, a RIS has
been developed by an in-house software development team and customized using
radiologists’ input to meet the requirements of a busy teleradiology practice.
4.3 Connectivity Requirements
With optical fiber cables traversing the depths of our oceans, high volume data transfer
across geographically separated locations, in the present day, is a non-issue. These high
speed connections allow Teleradiology service providers to serve clients half way around
the globe, with report turn-around times comparable to the ones from local radiologists.
An ideal connectivity solution for Teleradiology providers would be multiple T1 lines
which would each provide bandwidths of up to 1.544 Mb/s. A single radiologist working
from home may use DSL connectivity, provided adequate throughput is confirmed prior
to clinical use. Apart from bandwidth, one would also require other networking
components such as routers, firewalls, VPN concentrators, and intrusion detection and
As the service being provided is a clinical service, typically in the emergency
setting, a high level of communication between the site of origin and interpretation of the
images is mandatory. This involves the utilization of fax systems capable of handling
high volume data, direct telephonic contact and video and teleconferencing.
4.4 Data Standards
DICOM is the industry standard used for transfer of radiologic images between different
hosts claiming conformance. DICOM is a standard developed by a joint committee set up
by American College of Radiology (ACR) and National Electrical Manufacturers
Association (NEMA). HL7 (Health Level Seven) is the standard for the exchange,
management and integration of electronic healthcare information like clinical and
administrative data. Using HL7 compatible software streamlines the workflow
considerably. For example, if PACS and RIS of a Teleradiology practice are HL7
enabled, as soon as a new study is received by the PACS a new order is created on RIS,
using patient demography and study details from the DICOM file, eliminating duplication
5. Securing Patient Data
Teleradiology providers, being HIPAA  covered entities must have adequate privacy
and security practices defined, as Protected Health Information (PHI) and electronic
Protected Health Information (EPHI) are transmitted over public networks on a regular
basis. The Privacy Rule deals with all forms of patients’ protected health information,
whether electronic, written, or oral, while, the Security Rule covers only protected health
information that is in electronic form, including EPHI that is created, received,
maintained or transmitted.
Technical safeguards are relatively easy to implement. With a huge spectrum of
network security solutions available off the shelf today, building and managing a secured
network is not a huge challenge. What is significantly more challenging is stopping the
data from unauthorized access due to administrative breaches, and hence bulk of the
HIPAA privacy rules are to do with Administrative and Physical safeguards. These
breaches could only be plugged by educating employees about Privacy and Security
practices followed by the organization and ensuring that these practices are implemented.
The security rule does not prescribe any specific technologies – being technology
neutral allows covered entities to choose solutions based on their specific requirement.
Technical safeguard standards include Access Control, Audit Controls, Data Integrity,
Person or Entity Authentication and Transmission Security. Our in-house developed RIS
solution (Tele-RIS) is used as a case in point here to illustrate/demonstrate how it
complies with the above standards.
Access Control mechanisms are used to make sure that a person or software can
only access and modify resources he/she is authorized for. Access Controls standard
require the implementation of several features such as unique user identification,
automatic logoff, and data encryption procedures. In addition, the following functionality
also needs to be implemented:
Emergency Access Procedure: This implementation specification requires a covered
entity to establish procedures to retrieve EPHI during emergencies. Tele-RIS adequate
backup for power or network outages, but in case of a total outage, a backup procedure
for the entire workflow from order entry to report distribution is well defined. Operating
from different geographical locations also helps in dealing with contingencies.
Audit Controls: are useful for recording and examining information system activity,
especially when determining if a security violation occurred. Any addition, deletion or
remarkable modification on Tele-RIS is logged for audit purposes.
Data Integrity: Data could be altered during transit or in storage. EPHI that is
improperly altered or destroyed can result in clinical quality problems for a covered
entity, including patient safety issues. This could happen by both technical and non-
technical sources. A user can change the data, accidentally or maliciously. Tele-RIS
addresses this problem using techniques like data validation and normalization of
Person or Entity Authentication: Authentication involves confirming that users are
who they claim to be. Tele-RIS uses a username/password combination for
authentication. In recent times many applications incorporated the use of biometrics for
Transmission Security: This standard requires a covered entity to: “Implement technical
security measures to guard against unauthorized access to electronic protected health
information that is being transmitted over an electronic communications network.”
In this paper we describe the state-of-art in teleradiology and present a service delivery
model for providing cost-effective and flexible radiological services. The proposed model
can enable the delivery of radiological services to several hospitals independent of their
location and allows the exploitation of global time differences to provide emergency
night coverage in Emergency Departments. In addition, we also describe the technical,
regulatory and security issues related to teleradiology.
1. Emergency radiology coverage: technical and clinical feasibility of an international
teleradiology model. Kalyanpur A, Weinberg J, Neklesa V, Brink J and Forman H.
Emergency Radiology December 2003; 10(3) 115-118
2. Implementation of an International Teleradiology Staffing Model. Kalyanpur A.,
Neklesa V, Brink J., Pham, D., Stein S., Forman H. Radiology August 2004; 232:415-
3. Spigos D, Freedy Left, Mueller C. 24 hour coverage by attending physicians, a new
paradigm. Am J Roentgenol 167: 1089-1090
4. Health Care Financing Administration (1995) Medicare Program: Revisions to
payment policies and adjustments to the relative value units under the physical fee
schedule for the calendar year 1996 Fed Reg 60: 63124
5. Impact of Overnight Staff Coverage of a University Hospital Emergency Room via
International Teleradiology. Kalyanpur, A., Casey, S., Michel, E. RSNA December
2002, Chicago, IL
6. Evaluation of JPEG and Wavelet Compression for Teleradiology Transmission of
Direct-Digital Body CT Images. Kalyanpur A., Neklesa V. P., Taylor C. R., Daftary
A., Brink J. Radiology 2000 217: 772-779