Inf Syst Front (2009) 11:369–379 DOI 10.1007/s10796-009-9150-7
Automating object-oriented integration and visualization of multidisciplinary biomedical data in radiology workflow: Compartmental PACS model Alex K. S. Wong & Lawrence W. C. Chan & Ying Liu
Published online: 11 February 2009 # Springer Science + Business Media, LLC 2009
Abstract This paper is aimed to present a novel compartmental PACS model for the automatic object-oriented integration and visualization of heterogeneous data for the multidisciplinary biomedical studies in the midst of the imaging services in radiology department. The generic PACS is conceptually partitioned into two compartments: service and integration. The service compartment supports the routine imaging service by connecting the imaging modalities to the web client workstations through a single fault-tolerant hardware. The integration compartment is synthesized by open source and open standard software tools to perform the long-term archiving of imaging cases and to integrate the images with the related data from other clinical disciplines. The prototype of the compartmental PACS model has been successfully implemented in the Department of Health Technology and Informatics (HTI) at the Hong Kong Polytechnic University (PolyU). Multidisciplinary study on a cardiovascular case is considered as an example in this paper to demonstrate the seamless integration and web-based visualization of heterogeneous data from radiology, ophthalmology, cardiology and hematology. The implementation of the compartmental PACS model demonstrates a deliberative system design for A. K. S. Wong : L. W. C. Chan (*) Department of Health Technology and Informatics, Hong Kong Polytechnic University, Yuk Choi Road, Hung Hom, Hong Kong, People’s Republic of China e-mail:
[email protected] Y. Liu Department of Industrial and Systems Engineering, Hong Kong Polytechnic University, Yuk Choi Road, Hung Hom, Hong Kong, People’s Republic of China
allocating mission-critical components at the clinical frontline of imaging services and long-term archiving components at the backend. The integrative feature of object-oriented long-term archive addresses the comprehensive needs of patient-centered multidisciplinary biomedical studies. Keywords Multidisciplinary communication . Picture archiving and communications systems . Digital imaging and communications in medicine . Patient-centered care
1 Introduction PACS is sophisticated informatics infrastructure widely adopted in radiology and other clinical specialties like cardiology, and oncology due to its indispensable role in managing digital medical images and related information with excellent reliability, interoperability and scalability. The successes of PACS implementation and the related imaging applications have been observed in many clinical sites (Huang 2004). The adoption of picture archiving and communications system (PACS) is gradually increased in imaging informatics applications due to its interoperability with imaging modalities and the facilitation of retrospective and crosssectional studies. Through the adoption of cutting-edge information technology and the compliance of open standards, PACS can facilitate secure, speedy and ubiquitous communication of consistent information with the assurance of data integrity throughout the healthcare enterprise. However, the imaging modalities are manufactured in closed architecture to protect the benefits of manufacturers. Communication interface with open standard is usually
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unavailable from these commercial products, increasing the difficulty in the PACS adoption and tele-imaging applications. Another barrier to adopt the open standard and PACS for managing the imaging data is the high equipment and maintenance cost. In Hong Kong, the investment for implementing a commercial PACS is in millions of HKD. It is difficult to justify such huge investment without any potential improvement in the clinical service efficiency as the standalone diagnostic workstation has already fulfilled some important PACS functionality in the review of imaging cases. Quality services can have value added by collaborative multidisciplinary studies, which require heterogeneous data integration from various clinical disciplines and web-based visualization of the comprehended information among various collaborating sites at different geographic locations. Similar suggestions for multi-departmental PACS have been given in the literature (Bergh 2006; Crowe and Hailey 2002; Brennecke et al. 1992). The implementation of a web-based multi-agent architecture proves that the introduction of common healthcare standard is beneficial to the exchange of health records among multiple patient repositories (Choe and Yoo 2008). Therefore, the closed architecture of commercial PACS prohibits the data integration and subsequent web-based visualization though the web-based PACS image distribution has already been an option available in many commercial offerings. This paper presents a compartmental PACS model, which conceptually splits the generic PACS components into two compartments: service and integration. The service compartment supports the routine service as its first priority by connecting the imaging modalities to the web client workstations with a single hardware component, referred to as application server in this paper. The application server is fault-tolerant server hardware incorporating commercial PACS components, which are essential for maintaining the uninterrupted dataflow and streamlining the clinical services. The integration compartment is constructed by open source and open standard software tools to perform the long-term archiving of imaging cases and the integration of heterogeneous data from other clinical disciplines at a data center outside the clinical environment.
The merit of the proposed model is the deliberative compromise between commercial product and open source software in the PACS implementation. The commercial product can maintain reliable imaging services with highly available customer support. The adoption of open source software (OSS) packages and open standards ensures substantial cost reduction for long-term data archiving and facilitates the patient-centered multidisciplinary studies involving comprehensive data integration and web-based integrative data visualization. To validate the practical value of the compartmental PACS model, a prototype with the proposed system architecture was implemented at PolyU. In this paper, the Section 2 describes how a generic PACS can be used for the imaging and how a new model can be formulated to cater for the needs of cost reduction and multidisciplinary studies. It further presents the details about the architecture of the compartmental PACS with the descriptions of individual components. In Sections 3 and 4, the compartmental PACS model is validated at PolyU by assessing its clinical value in supporting imaging services and its integrative feature in the related multidisciplinary biomedical studies.
2 Methods 2.1 Derivation from Generic PACS The compartmental PACS model originates from a deliberative system design to leveraging the benefits of the strategic hardware and software allocation in a generic PACS architecture. Figure 1 illustrates the architectures with dataflow of a generic PACS. The computed tomography (CT) is regarded as the imaging modality in the model where patient and study information can be manually entered and merged with the pixels of the CT to form digital images in the digital imaging and communication in medicine (DICOM; Digital Imaging and Communications in Medicine 2007) format. The DICOM images will be sent to the acquisition gateway for temporary storage. When the PACS controller is idle, the images will be pushed to PACS controller where
Fig. 1 Architecture of a generic PACS and dataflow for radiology
Short-term Archive Patient & study information
Imaging Modality
Acquisition Gateway System Log PACS Monitor
DICOM Storage
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PACS Controller DICOM Storage DICOM Query / Retrieve Web Application Server
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the images will be stored at both short-term and long-term archives. The auto-routing of PACS controller can send the latest imaging cases to the web application server for web distribution of CT images. Commercial offerings of PACS always supply all the above-mentioned components. Large proportion of the investment falls into the purchase and maintenance of the PACS controller, long-term archive and PACS monitor, which are not mission-critical in the routine imaging services. Moreover, PACS controller is one of the singlepoint-of-failure’s (SPOF’s), determining the continuous operation of the PACS. It is not rare to observe PACS downtime when a minor hardware problem happens at the PACS controller or the long-term archiving. As the mission of the PACS controller is so critical, it is almost impossible to receive data from other clinical disciplines, such as ultrasound images, and integrate the heterogeneous data at the PACS controller and long-term archive. The compartmental PACS model suggests using the OSS packages to build the PACS controller, long-term archive and PACS monitor with open standards and migrating these components from the clinical environment to a data center. The acquisition gateway, short-term archive and web application server are combined into a single hardware, application server. This move has three advantages for imaging services. First, the use of OSS package reduces substantially the cost. Second, there is only a single hardware operating in the clinical environment, reducing the chance of system breakdown and the maintenance cost in running these components in the clinical environment. Third, the use of open standards facilitates heterogeneous data integration in multidisciplinary studies. Based on the DICOM standard, the integration compartment provides a
common platform for integrating the imaging cases with the biomedical data from other related clinical disciplines, such as cardiology and neurology. 2.2 Formation of compartmental PACS model The proposed model consists of clinical application and integration compartments. Figure 2 illustrates the architectures with dataflow of the compartmental PACS. There are eight major actions in the dataflow of the compartmental PACS: (1) Acquisition gateway receives the DICOM CT images from the imaging modality; (2) The DICOM images will be sent to the short-term archive and the PACS controller after the validation of DICOM format; (3) The PACS controller sends the received DICOM images to the long-term archive through the network file system (NFS) connection; (4) Web application server closely attached with the short-term archive serves the web clients with the study list, the DICOM images and the reporting function through Hypertext Transfer Protocol (HTTP); (5) Web clients can query and retrieve the PACS controller for the historical imaging cases at the long-term archive through the web application server; (6) Imaging reports can be written at web clients and submitted to the web application server through HTTP. The imaging case reports will be converted to the DICOM Structured Reporting (SR) objects; (7) Short-term archive sends the DICOM SR objects to PACS controller; (8) PACS controller stores the DICOM SR objects to the long-term archive. As mentioned in the previous session, acquisition gateway, short-term archive and Web application server are logically integrated into a single hardware, called application server, at the service compartment. To stream-
Fig. 2 Architecture of the compartmental PACS. Dataflow
Application Server Patient & study information
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line the clinical dataflow, the DICOM images are directly sent to the short-term Archive to avoid unnecessary network traffic. At the integration compartment, there are two hardware components: control server and data server. The control server logically comprises the PACS Monitor and PACS controller, while the data server acts as the longterm archive. 2.2.1 Acquisition gateway There is need for verifying the data format of the DICOM images before image archiving and distribution. The acquisition gateway acts as check point and data buffer for verifying and handling the images sent from the imaging modality and automatically routes them to the short-term archive internally within the same hardware and the PACS controller through the DICOM communication protocol if the format is correct. 2.2.2 PACS controller, long-term archive and PACS monitor A third-party application service provider (ASP) is responsible for hosting and maintaining the hardware for the PACS controller, long-term archive and PACS monitor. The hardware includes a control server and a data server, which are connected physically by optical fiber and logically by mounting a network file system (NFS) folder. Running inside the control server is a DICOM archive program, which was developed by the research team based on the OSS packages including DICOM Toolkit (DCMTK; Eichelberg et al. 2004), hypertext preprocessor (PHP) libraries (Hypertext Preprocessor 2007) and MySQL (MySQL 2007). When a DICOM image is sent to the PACS controller, the DICOM archive program will parse the DICOM header of the image file and insert the parsed patient and study information into the tables of the MySQL database. After the data insertion, the DICOM image will be sent to the short-term and long-term archives for storage. The data server plays a very important role as a long-term archive for providing huge storage capacity, saying hundreds of terabytes (TB), and facilitating almost unlimited extension of storage capacity. The PACS monitor is a software program developed by the research team based on the PHP and MySQL. The major functions of the PACS monitor are to monitor the system status and image queuing of the acquisition gateway, PACS controller, short-term and long-term archives and web application server and to present the information through a PHP website hosted by the control server. The features of the compartmental PACS are not only limited to strategic hardware and software allocation between the service compartment and the integration compartment, but also the use of the OSS packages
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including DCMTK, PHP libraries and MySQL and the open standards. These packages, incorporated with DICOM, hypertext transfer protocol (HTTP) and structured query language (SQL) as the open standards, make the critical IT functions, under the full control of the research team and the technical support of the ASP, rather than the software and hardware vendors. The DICOM-based data model and the OSS packages, used for building the PACS controller, will be further elaborated as follows. DICOM-based data model Model-driven system development has been widely adopted in the enterprise level (Yu et al. 2007). Object-oriented approach provides the way to identify clearly the structural and behavioral states of the electronic record, communication signal or message (Park et al. 2007; Houssos et al. 2004) and there exist many conceptual toolkits for relevant system design (Eden 2002), thus it is inherently applicable to the medical images and related data too. The information object definition (IOD; National Electrical Manufacturers Association 2008) provides an object-oriented data model of medical data, so called DICOM objects, including medical images, graphics, waveforms, textual reports, audios, videos and printings, and also encourages the multidisciplinary object-oriented approach for the integration and communication of these objects. The IOD specifies the DICOM attributes, including the description of any medical images produced by common imaging modalities. The CT images in DICOM format, which can be generated by CT scanners, are regarded as DICOM CT objects. Manufacturers also attempted to implement DICOM SR for recording the image-associated evidence and findings and also the computer-aided diagnosis (CAD) results (Sluis et al. 2002). Coinciding with the basic concept of data model (Marcos and Marcos 2004), the object-oriented data model in DICOM standard reserves three basic properties, closelypacked byte stream, self-contained patient and study information and cross-referencing between objects (Chan et al. 2008). Through the format of closely-packed byte stream, any addition or removal of data in a DICOM object during the transmission can be easily detected, ensuring the data integrity within the DICOM objects. The selfcontained patient and study information guarantees the availability of patient and study information during the ubiquitous data distribution and exchange out of reach of the clinical information database. The cross-referencing of study instance unique identifier (UID) between objects ensures the data integrity for multidisciplinary studies. Figure 3 illustrates the DICOM-based data model used for building the PACS controller at the integration compartment. The DICOM standard is now widely adopted by many clinical disciplines such as cardiology, radiology, pathology, dentistry, endoscopy, mammography, ophthalmology, radi-
Inf Syst Front (2009) 11:369–379 Fig. 3 Object-oriented data model based on DICOM standard—The relational database of the PACS controller consists of four tables: patient, study, series and object. The records of these tables are linked up with keys uniquely identified for each table. Two kinds of DICOM objects: CT and SR, can be found at the path given by the ObjectPath of the object table. These two objects can also be cross-referenced through the common study instance UID embedded in the objects
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Patient table PatientKey
PatientID
PatientName
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A123456 …
John Harris …
PatientDOB PatientSEX
19771231 …
M …
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StudyID
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S234567 …
20071231 …
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Series table SeriesKey
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3 1 …
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/archive/200712/74975.dcm
1576 1576 1576 1577 …
/archive/200712/74976.dcm /archive/200712/74977.dcm /archive/200712/74978.dcm
…
Computed Tomography (CT)
Structured Report (SR) Patient Name: John Harris Patient ID: A123456 Age / Sex: 30 / M Fundus Exam Report: Findings: Xxxxxxxxxxxx Xxxxxxxx Comment: xxxxxxxxxxxxx Optometrist: xxxxxxx
ation therapy, orthopedics, pediatrics and surgery. The integration compartment of the compartmental PACS can be further developed to be a multidisciplinary DICOM multimedia archive (MDMA; Chan et al. 2008), which is able to inherit the properties of DICOM compliance in the data format and communication and to facilitate the integration and visualization of any DICOM objects. OSS packages Offered by Oldenburg Research and Development Institute for Information Technology Tools and
Systems (OFFIS), DCMTK is a collection of DICOMrelated libraries and applications for DICOM file processing and communication, including image storage, indexing and worklist servers (Eichelberg et al. 2004). The source code of DCMTK was synthesized using ANSI C and C++ scripting languages and was made available at the official website of OFFIS. DCMTK can be compiled and implemented on various operating system platforms including Windows, Linux, Solaris, QNX, IRIX, Free/Net/OpenBSD and MacOS X. With the high reliability achieved through
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continuous enhancement, DCMTK has been adopted by different institutes, hospitals and companies as a product testing tool and a building block for research projects, prototypes and commercial products. In the compartmental PACS, DCMTK is used to construct the DICOM services for the storage, indexing and query/retrieve of images and reports. PHP is a general-purpose scripting language for system development. There are a large number of open source PHP libraries, especially those for implementing the DICOM compliance. For the sharing of reusable PHP components among developers, PHP extension and application repository (PEAR) provides a framework and distribution system for uploading and downloading useful open source PHP scripts (PHP Extension and Application Repository 2007). In the compartmental PACS, “DICOM.php” and “Element. php”, downloadable from PEAR, are two essential PHP scripts, which are used for parsing the headers of the DICOM images received at the PACS controller. As shown in Fig. 4, these two open source PHP scripts are initiated by the DICOM storage service class provider (storage SCP) to parse patient and study information from the DICOM header. The parsed information is used to determine the storage path in the long-term archive and the destinations of further image routing. The PHP script, “Storage.php”, is developed by the research team to automate the execution of the storage and indexing functions provided by DCMTK and the long-term archiving. The object index formed in the database is used for the query/retrieve (Q/R) functions illustrated in Fig. 5. Acquisition Gateway Image
Web Application Server (1)
Report
Storage SCP
As the PHP scripts can be easily embedded into hypertext markup language (HTML) pages, PHP is widely used in web-based applications gearing with high performance database management system. In contrast with the off-the-shelf commercial products such as Oracle, MySQL is popular open source database management software providing comparably high querying speed, reliability, universal interfacing and ease of use. Through the SQL and the universal interface facilitated by open database connectivity (ODBC), any third-party software programs can access the MySQL database seamlessly and securely with minimal system integration efforts. As an alternative to expensive commercial software, MySQL is playing an indispensable role in the fast growing open source web server software stack, comprising of Linux, Apache, MySQL, PHP/Perl/Python (LAMP), with minimal system integration cost. In the compartmental PACS, the acquisition gateway and the PACS controller report continuously their status and data objects queues by updating the system event logs stored in the MySQL database tables. It is shown in Fig. 6 that the PHP scripts are used to present the system and queue status logs to the system administrator at the integration compartment and to notify the clinical staff with such events in an intuitive way at the service compartment. 2.2.3 Short-term archive Off-the-shelf commercial software packages, PowerServer, PowerCache and PowerReader developed by RamSoft Inc., are used for short-term archiving, web-based image
Short-term Archive (5)
Image
Storage SCU
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Database Long-term Archive
Storage.php (2) DICOM.php
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Fig. 4 Archiving and auto-routing dataflow of PACS controller—(1) Storage SCP receives the images and reports, which are regarded as DICOM objects, from the acquisition gateway and the web application server respectively and triggers the “Storage.php” program; (2) “Storage.php” initiates “DICOM.php”, “indexing”, storage SCU and
PACS Controller
long-term archiving; (3) “DICOM.php” parses the headers of the DICOM objects and determines the archiving paths and whether autorouting is required; (4) “Indexing” records essential information extracted from the headers and the archiving paths to the database; (5) Storage SCU sends out the images to the short-term archive
Inf Syst Front (2009) 11:369–379 Fig. 5 Query/Retrieve dataflow of PACS controller—(1) Shortterm archive initiates a request for query/retrieve an imaging case; (2) Q/R SCP looks up the database and gets the path of the requested case; (3) Q/R SCP obtains the requested case from the long-term archive and sends it to the short-term archive
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Short-term Archive Imaging case Storage SCP
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distribution, reporting and review. PowerServer, as shortterm archive software, receives DICOM images from the acquisition gateway through the DICOM storage service within the same hardware, parses and inserts the patient and study information into a local database, and stores the photographs to the partitions of the local redundant array of inexpensive disks (RAID). The maximum capacity of the RAID should be large enough to store the imaging cases in the recent 1 month. The auto-delete function of PowerServer detects the used storage capacity. When the used capacity reaches the upper water level, say 90% of maximum capacity, PowerServer purges the old cases
Any web browsers
Web Services: HTML, PHP
Event logs Database System and queue status
Acquisition Gateway PACS Controller
PACS Monitor
Fig. 6 Operation of PACS monitor—The database collects all the event logs from the acquisition gateway and PACS controller and provides the system administrators with the system and queue status though the web services
PACS Controller
leaving the latest cases until the used level returns to the lower water level, say 80%. Besides DICOM CT objects, PowerServer can archive many other medical images and the reports written by the radiologists through the web clients. The reports produced at the frontline will be converted into DICOM SR objects. As for the data of the same patient and the same case, other relevant medical images and structured reports are merged with the CT images into the same folder when being presented in the study list. 2.2.4 Web application server and web clients PowerServer also acts as the web application server, providing web service for streaming the medical images and the related information to the web clients through the HTTP, which is the basic web-based communication service (Umapathy and Purao 2007). PowerReader will be installed at the web clients when the users log in the welcoming webpage hosted by PowerServer for the first time. PowerReader is web-based interpretation and clinical review software bundled with every PowerServer edition. It includes all of the navigation, manipulation, annotation tools that are common in a clinical diagnostic viewing package and a number of specialized features that enhance reading from certain imaging modalities. Through PowerReader, the users can also query the PACS controller and retrieve the historical cases from the long-term archive. The speed of retrieval depends on the retrieving priority requested by the users. For every time a case is displayed through PowerReader, the case will be retrieved from PowerServer and stored by PowerCache at the web client. Deployed at each web client, PowerCache is a temporary online storage persistently connected with PowerServer so
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that the users do not have to wait for images and reports to download. With the confirmation of the radiologists, the DICOM SR objects, which encapsulate the examination reports, are sent to the PACS controller through PowerServer for the long-term archiving, as shown in Fig. 2.
3 Results The prototype of the compartmental PACS has been implemented at PolyU. The clinical value and integrative feature of the compartmental PACS are demonstrated as follows. 3.1 Clinical value Software components of service Compartment includes acquisition gateway, short-term archive and web application server are installed in single computer hardware, application server. Such architecture avoids tedious troubleshooting tasks for checking the connectivity problem between components. Fault-tolerant hardware, including clustering and load-balancing, is used to build the application server. Single hardware further streamlines the imaging dataflow as the images can be sent to both short-term and long-term archives simultaneously and immediately ready for webbased distribution. For the generic PACS, the images have to be handled by the PACS controller before reaching the web application server for further image distribution. 3.2 Integrative feature Besides the clinical value, the merits of the compartmental PACS are the seamless integration of biomedical data from various related clinical disciplines at the integration compartment and the comprehensive display at the web client of the service compartment. The CT images can provide the basic information about the anatomical structure of the organs or tissue involved in the cardiovascular diseases. Fundus photographs are used to identify and assess retinal microvascular abnormalities using standard grading of lesions at quadrants of retina or quantitative indicators such as arteriole-to-venule ratio (AVR). Such abnormalities, including microaneurysms and arteriovenous nicking, reflect pathological changes from hypertension and other vascular diseases and have a significant association with cardiovascular events, such as stroke and coronary heart disease (CHD) as shown in cohort studies (Wong et al. 2001; Cheung et al. 2007). A common platform for integrating, visualizing and analyzing the CT images with other related data, such as fundus photographs, carotid ultrasound images, cerebral arterial blood flow velocity and biomarker profiles, could definitely
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inspire the multidisciplinary studies in cardiovascular risk assessment. The integration compartment facilitates such a common platform to integrate the biomedical data of the same patient through the DICOM standard. Besides the DICOM CT images, the biomedical data—which include DICOM Ophthalmology (OP) images (Lamminen 2003), DICOM Ultrasound (US) images at carotid arteries, DICOM SR of biomarker profile and DICOM Hemodynamic (HD) waveforms of blood flow velocity at cerebral arteries—can be integrated by the integration compartment. These DICOM objects can be cross-referenced through the patient and study identifiers, stored at the long-term and short-term archives, and displayed through the web viewer at the web clients. Figure 7 depicts a hypothetical case consisting of all these DICOM objects of the same patient displayed in parallel using the RamSoft PowerReader. This case highlights the significance of the compartmental PACS in conducting the multidisciplinary studies in cardiovascular diseases.
4 Discussions The compartmental PACS positions the communication and long-term archiving of images and reports and the PACS monitoring as the data archiving services. The model retains the clinical staff’s full control of image acquisition, display, reporting and review at the service compartment. The major driving force of this model implementation is the streamlined and fault-tolerant clinical image distribution and the economical outsourcing of routine data archiving and PACS monitoring to the right party ASP. Unlike the service compartment, the operation of long-term archiving of imaging cases does not require clinical knowledge and experience. Reliable hosting of such computing facilities requires personnel with substantial IT system administration experience only. As the long-term archive normally requires huge storage capacity, it is preferable to host these particular applications at a large-scale informatics infrastructure provided by an ASP. The ASP hosting favors the incorporation of OSS. Through continuous bug reporting and fixing by developers, the technology of some OSS packages, such as DCMTK, has become more sophisticated than the commercial products. The OSS packages provide economical software building blocks with reduced cost of software upgrades and no license expiration. The disappearance of software vendors or the discontinuity of maintenance services no longer threatens the end-users because the source code of the OSS has already been obtained. Further, the future expansion and upgrade of the clinical application facilities will not be tied by particular software vendors since the OSS and open standards provide open architecture
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Fig. 7 Integrated display of DICOM objects of the same patient provided by different clinical disciplines—Top left, fundus photograph; Top right, Doppler ultrasound at middle carotid artery; Middle
left, CT head image; Bottom left, hierarchical tree of DICOM objects; Bottom center, structured report; Bottom right, trans-cranial Doppler (TCD) ultrasound waveform
for system development and integration. Inherent compliance of open standards usually comes with the OSS distribution, facilitating the system interoperability among other OSS or proprietary software packages. As single application server hardware is used, the architecture of the service compartment avoids the connectivity problems and eliminates the needs for the corresponding troubleshooting. Moreover, the long-term archiving at the integration compartment does not require validating the format and the header information of the DICOM image because the validation has been performed by the acquisition gateway during the data acquisition. Having these strategic sakes, the implementation of the compartmental PACS at PolyU proved streamlined clinical dataflow with substantial cost reduction, effectively addressing the issues pointed out in the literature (Crowe and Hailey 2002). The cardiovascular case demonstrates a successful webbased visualization of heterogeneous data, achieving the
critical success factors for system integration mentioned in (Bergh 2006) with the use of open standards and OSS. With the system interoperability retained by the open standards, the integration compartment can also acts as a multidisciplinary multi-media archive (Chan et al. 2008), which will be readily shared with clinics in other specialties, yet facilitating multidisciplinary studies. The authors foresee that the heterogeneous data can be fused to locate the pathological sites with biomedical analysis results as their attributes and the visualization can be layered across the biological continuum (Poh et al. 2007) automatically under this multidisciplinary platform.
5 Conclusions Clinical value and integrative feature comprise major considerations to the design of imaging informatics hardware and software infrastructure. This paper present a
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compartmental PACS model based on OSS with open standards for imaging informatics applications. The model provides a deliberative allocation of hardware and software between the service compartment and the integration compartment, streamlining the imaging services with reduced cost and automating the seamless integration and web-based visualization of biomedical data from multiple clinical specialties. With free license and no expiration, the OSS further reduces the cost of system implementation, customization and maintenance. The release of source code also alleviates the threat induced by the transience of vendors. The open standards are also inherently complied by the use of OSS, ensuring the system interoperability and also making the imaging-related multidisciplinary studies, such as on cardiovascular diseases, possible. Having these benefits, the prototype of the compartmental PACS has been successfully implemented at PolyU to testify the betterment of both clinical practice and multi-centre collaborative studies with web-based integrative data visualization of heterogeneous data outside the missioncritical clinical environment. Acknowledgment We would like to thank for the donation of RamSoft software license from INQGEN Limited to this research study. This research is supported by the Internal Fund of PolyU “1-ZV39: PACS-based Intelligent Risk Assessment of Diabetic Complications.”
References Bergh, B. (2006). Enterprise imaging and multi-departmental PACS. European Radiology, 16, 2775–2791. Brennecke, R., Lang, M., Fritsch, J. P., Erbel, R., Meyer, J. (1992). A framework for PACS development in cardiology. Comput Cardiol 1992 Proceedings, Durham, NC, USA, pp. 259–261. Chan, L. W. C., Chan, S. T., Zheng, Y. P., Wong, A. K. S., Liu, Y., & Benzie, I. F. F. (2008). DICOM-based multidisciplinary platform for clinical decision support: Needs and direction. In Y. Liu, A. Sun, H. T. Loh, W. F. Lu, & E. P. Lim (Eds.), Advances of computational intelligence in industrial systems, in the series of computational intelligence (375 pp.). Berlin: Springer. Cheung, N., Wang, J. J., Klein, R., Couper, D. J., Sharrett, A. R., & Wong, T. Y. (2007). Diabetic retinopathy and the risk of coronary heart disease: The atherosclerosis risk in communities study. Diabetes Care, 30(7), 1742–1746. Choe, J., & Yoo, S. K. (2008). Web-based secure access from multiple patient repositories. Int J Med Inform, 77, 242–248. Crowe, B., & Hailey, D. (2002). Cardiac picture archiving and communication systems and telecardiology—Technologies awaiting adoption. Journal of Telemedicine and Telecare, 8 (Suppl. 3), S3:9–S3:11. Digital Imaging and Communications in Medicine. (2007). Retrieved 19 December 2007 from http://medical.nema.org. Eden, A. H. (2002). A theory of object-oriented design. Information Systems Frontiers, 4(4), 379–391. Eichelberg, M., Riesmeier, J., Wilkens, T., Hewett, A. J., Barth, A., & Jensch, P. (2004). Ten years of medical imaging standardization and prototypical implementation: The DICOM standard and the
Inf Syst Front (2009) 11:369–379 OFFIS DICOM Toolkit (DCMTK). In: O. M. Ratib & H. K. Huang (Eds.), Medical imaging 2004: PACS and imaging informatics. Proceedings of SPIE, 5371, pp. 57–68. Houssos, N., Gazis, V., & Alonistioti, A. (2004). Enabling delivery of mobile services over heterogeneous converged infrastructures. Information Systems Frontiers, 6(3), 189–204. Huang, H. K. (2004). PACS and imaging informatics: Basic principles and applications. New York: Wiley. Hypertext Preprocessor. (2007). Retrieved 19 December 2007 from: http://www.php.net. Lamminen, H. (2003). Picture archiving and fundus imaging in a glaucoma clinic. Journal of Telemedicine and Telecare, 9, 114– 116. Marcos, E., & Marcos, A. (2004). A philosophical approach to the concept of data model: Is a data model, in fact, a model? Information Systems Frontiers, 3(2), 267–274. MySQL. (2007). Retrieved 19 Dec 2007 from http://www.mysql.com. National Electrical Manufacturers Association. (2008). DICOM part 3— Information object definitions. Retrieved 2 Jan 2008 from http:// medical.nema.org/dicom/2007/07_03pu.doc. Park, H. A., Cho, I. S., & Byeun, N. S. (2007). Modeling a terminology-based electronic nursing record system: An objectoriented approach. International Journal of Medical Informatics, 76, 735–746. PHP Extension and Application Repository. (2007). Retrieved 19 Dec 2007 from http://pear.php.net. Poh, C. L., Kitney, R. I., & Shrestha, R. B. (2007). Addressing the future of clinical information system—Web-based multilayer visualization. IEEE Transactions on Information Technology in Biomedicine, 11(2), 127–140. Sluis, D., Lee, K. P., & Mankovich, N. (2002). DICOM SR— Integrating structured data into clinical information systems. Medicamundi, 46(2), 31–36. Umapathy, K., & Purao, S. (2007). A theoretical investigation of the emerging standards for web services. Information Systems Frontiers, 9(1), 119–134. Wong, T. Y., Klein, R., Couper, D. J., Cooper, L. S., Shahar, E., Hubbard, L. D., et al. (2001). Retinal microvascular abnormalities and incident stroke: The Atherosclerosis Risk in Communities Study. Lancet, 358(9288), 1134–1140. Yu, X., Zhang, Y., Zhang, T., Wang, L., Hu, J., Zhao, J. H., et al. (2007). A model-driven development framework for enterprise web services. Information Systems Frontiers, 9(4), 391–409.
Alex Ka Shing Wong was born on 22nd March 1979 in Hong Kong, China. He received Bachelor’s and M.Phil. degrees from the Department of Computing in The Hong Kong Polytechnic University, in 2002 and 2008, respectively. He is currently Research Associate at the Department of Health Technology and Informatics in The Hong Kong Polytechnic University. He was the Vice President of the IEEE SMC Student Branch (PolyU). His main research interests include Machine Learning and Information System for Medical Applications. Dr. Lawrence Wing-Chi CHAN is currently Assistant Professor in the Department of Health Technology and Informatics at the Hong Kong Polytechnic University. Dr. Chan received the degrees of Bachelor of Engineering with first class honors and Doctor of Philosophy from the Department of Mechanical Engineering at the University of Hong Kong. He was investigating the combined use of fuzzy logic and neural network in modeling nonlinear stochastic systems in his postgraduate study. After graduation, he worked in
Inf Syst Front (2009) 11:369–379 Jockey Club Research and Information Center for Landslip Prevention and Land Development as Database Administrator at the University of Hong Kong. From 2002 to 2006, he joined the Hong Kong Polytechnic University as Research Associate and then promoted to Research Fellow in the field of medical imaging. His current research interests include intelligent health knowledge discovery, multidisciplinary clinical decision support and biomedical image and signal processing. He is actively conducting the integrated analysis of the atherosclerotic risk factors and the subsequent risk assessment of diabetic individuals. Dr. Chan has published 10 SCI journal papers, one of which has been non-self cited for 29 times, and two book chapters, presented 21 conference papers or posters, granted or filed three patents, and received two international awards for the innovative mobile computing application in medicine.
379 Dr. Ying Liu is presently a Lecturer with the Department of Industrial and Systems Engineering at the Hong Kong Polytechnic University. He obtained his Ph.D. from the Singapore MIT Alliance (SMA) at the National University of Singapore in 2006. His current research interests focus on design informatics, data mining and text mining, intelligent information processing and management, machine learning, and their joint applications in engineering design, manufacturing and medical and healthcare industry for knowledge discovery and management purpose. He is the lead editor for the book “Advances of Computational Intelligence in Industrial Systems” Springer 2008 and he has served as the lead guest editor for several journals like Journal of Intelligent Manufacturing and Information Systems Frontiers. He is a member with ACM, IEEE, ASME and the Design Society.
