Integrating images into the electronic patient record of the hospital authority of Hong Kong

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Abstract

Over a period of 10 years the Hospital Authority has developed an integrated clinical information system (The Clinical Management System—CMS), including a territory-wide longitudinal electronic patient record (ePR). The CMS and ePR are used by over 4000 doctors and 20,000 other clinicians to document and review care. The ePR currently has nearly 3TB of data covering 44 million episodes for 6.4 million patients.

To date the CMS has largely dealt with textual data. However, PACS technology is increasingly being adopted in the HA. This paper describes our strategy for taking the hospital image archives and making them available throughout the Authority as part of the longitudinal patient record, leveraging the ePR to distribute radiological and other images in a manner which is integrated, affordable and sustainable.

Introduction

The Hospital Authority (HA) was established in 1990 to manage all the public hospitals in Hong Kong. Today the HA manages 43 hospitals and institutions and numerous specialist and general outpatient clinics. The HA manages 29,000 beds and employs 49,000 staff. Annually there are over 1 million inpatient episodes, over 2 million Accident and Emergency visits, and over 6 million specialty outpatient visits.

Section snippets

Clinical information systems in the HA

Since the early 1990s the Hospital Authority has been building a corporate wide clinical informatics portfolio to better support the delivery of patient care.

The Clinical Management System

In 1994 the Hospital Authority began developing the Clinical Management System (CMS), an integrated clinical workstation giving clinicians access to all available electronic clinical information as well as providing direct entry of orders and care or patient documentation [1]. The CMS has also been the platform for development of all subsequent clinical modules, including modules for different clinical specialties, the allied health disciplines and different care settings.

The CMS has been

The Electronic Patient Record

The Electronic Patient Record (ePR), developed since 1999, brings together all the information from the various clinical modules of the CMS into one corporate-wide, longitudinal, integrated record. The ePR has been built as a massive clinical repository accessed by an intuitive web-based front end (Fig. 1). The ePR was developed using the Hospital Authority's Information Architecture, which describes both the macroscopic and detailed structure of the ePR, as well as supporting the concept of

The network infrastructure

All the hospitals in the Hospital Authority are connected to both corporate data centres by high speed leased data lines. These lines vary in bandwidth from 50 Mb/s for all the major acute hospitals down to 2 Mb/s for the smallest institutions. Utilization of the wide area network (WAN) is actually highest after-hours when data backup is performed from the hospital data centres to the corporate data centres (Fig. 2).

Within hospitals the local area networks (LANs) have 100 megabit to Gigabit

PACS in the HA

Picture Archiving and Communications Systems (PACS) technology has been acquired on a local basis, often in conjunction with a major modality acquisition (from hereon these systems shall be referred to as ‘mini-PACS’). As a result of this, mini-PACS systems from a variety of vendors are currently implemented in the HA environment. These systems have typically been managed entirely by the radiology department and the PACS vendor, with minimal involvement of either the ward clinicians or the

The need for image distribution

As with any site that has digital imaging in place, it makes sense to make the best use of these images by delivering them electronically wherever they are required. However, in the Hospital Authority, there have been two specific drivers behind the ePR-image integration project: (1) Patient movement (2) Remote access to images.

Patient movement

In the Hong Kong there has always been a great deal of patient mobility due to the small geographic size of the whole territory. With the organization of hospitals into seven clusters there has also been increasing movement of patients between hospitals within a cluster, as services are rationalized and different aspects of care are often provided at different hospitals in the cluster. This movement of patients has been a major driver for the ePR, as the ePR makes key clinical data available no

Remote access to images

One major advantage of electronic images is the ability to send these images to an off-site radiologist for review. Many of the hospitals with mini-PACS systems have been considering extending their systems to allow transmission of images off-site, often to the radiologists’ homes for after-hours review. As the Hospital Authority has very strict security controls on network traffic beyond the corporate firewall these would be non-trivial endeavours. The ePR-image integration project will

The ePR-image distribution architecture

The ePR-image distribution project attempts to meet these needs whilst leveraging the existing PACS implementations and the extensive clinical information infrastructure already in place. The intent is to provide corporate wide distribution of radiological images to clinical workstations at a fraction of the cost that would be required for a ‘full’ PACS implementation.

The proposed image distribution architecture is shown in Fig. 3. DICOM (Digital Imaging and Communications in Medicine) images

Implementation and technical details

As noted above leverage of existing resources is a key aspect of this project. We have already deployed nearly 10,000 workstations throughout the Hospital Authority to access the CMS and ePR. The existing workstations vary in their specifications but almost all meet or exceed the minimum requirements that other authors have described (350 Mhz Pentium II PC with 128 Mb RAM and a 15′ LCD screen at 1024×768 resolution) and the 10/100 Base T network currently in place should be sufficient for

Discussion

Although PACS is now a well-established technology, achieving a filmless environment using PACS is still a high cost venture. Massive storage, very high reliability and diagnostic grade workstations remain expensive. In an enterprise environment such as in the Hospital Authority the costs can be especially high as WAN bandwidth is much more expensive than LAN bandwidth, and the storage requirements are daunting. Unfortunately over the last 25 years image storage requirements have grown at a

Lossy compression

One solution that has been much discussed in the literature is the use of lossy compression. A study of computer-generated images found that for JPEG compression, 15x compression represented the ‘visually lossless’ threshold [10]. Studies using real images have found different results for different modalities. Brain lesion detection with magnetic resonance imaging (MRI) is not adversely affected by 10–20× wavelet compression, depending on the pixel size [11]. Ultrasound images can be compressed

Image distribution versus ‘Full PACS’

The main purpose of the image distribution architecture is to leverage the existing clinical information infrastructure to deliver reference quality images to clinicians, in the absence of sufficient resources to implement a ‘full’ PACS. The main differences between this project and a ‘full’ PACS are as follows:

  • (1)

    This is not a filmless project. The use of lossy compression greatly reduces the demand on storage and network bandwidth but means that film will still have to printed; the lossy images

Conclusion

PACS is no longer a cutting edge technology, and there are some very large-scale PACS implementations around the world [22]. The Hospital Authority is taking a very low cost approach that leverages existing infrastructure but which still aims to provide many of the benefits of PACS—especially the timely delivery of radiology images to clinicians through the longitudinal electronic patient record.

Acknowledgements

We would like to thank the members of the Radiology Information Systems Steering Group, the PACS Technical Advisory Group, the ePR Task Force, and the Information Technology Department for their work in the development of the image distribution project.

Dr NT Cheung, MBBS, MSc(Comp Sci) is the Executive Manager, Health Informatics at the Hong Kong Hospital Authority (HA). He has been involved in the medical informatics field since 1985 when he worked on one of the first GUI-based clinical software packages in existence. He joined the Hospital Authority in 1993 and with a unique combination of medical and IT qualifications he led the development of the Clinical Management System (CMS), the HA's integrated clinical workstation. His interests

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  • Cited by (0)

    Dr NT Cheung, MBBS, MSc(Comp Sci) is the Executive Manager, Health Informatics at the Hong Kong Hospital Authority (HA). He has been involved in the medical informatics field since 1985 when he worked on one of the first GUI-based clinical software packages in existence. He joined the Hospital Authority in 1993 and with a unique combination of medical and IT qualifications he led the development of the Clinical Management System (CMS), the HA's integrated clinical workstation. His interests include clinical process improvement, clinical systems architecture, user interface, medical terminology, and knowledge representation and he continues to improve the already world-class facilities in the CMS for the documentation and effective management of diseases and care. His current focus is on taking CMS on a generational leap to the next level of computerized record system functionality.

    Amber LAM, MBA, is the Senior Systems Manager of the Information Technology Department of the Hospital Authority of Hong Kong. She has been involved in the development and implementation of clinical systems for the Authority since 1991. In addition, she has been part of the team in the consultancy study on Enterprise PACS Solution for the Authority in year 2002 followed by a pilot project to integrate existing digitized images to electronic Patient Records in year 2004.

    William WT CHAN, MBA, is the systems manager of the Information Technology Department of the Hospital Authority. He has been working on the integration of multi-vendors PACS systems with the HA-build Radiology Information System since 1997. His current project is to integrate images into electronic Patient Records and distribute them to all hospitals and clinics within Hospital Authority.

    Dr James HB Kong, MBBS, FRCSE, FRACS, FHKAM (Surgery) is the Consultant Health Informatics of the Hong Kong Hospital Authority where he leads the Health Informatics team to assist the Information Technology Division in providing support to the core services of the Hospital Authority. He has been interested and involved in the development of systems starting early during his post-graduate training. He was previously the Consultant Surgeon in charge of the Breast Service and Director of Trauma at Pamela Youde Nethersole Hospital. He has worked on numerous task forces and chaired the Hospital's Medical Records Committee for many years. He continues to teach, both undergraduates and resident surgical trainees as Honorary Associate Professor at the Faculty of Medicine, Chinese University.

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