OPHTHALMOLOGIC ELECTRONIC HEALTH RECORDS

SYSTEM USING HL7/CDA AND DICOM - TELEOFTALWEB

Isabel de la Torre, Roberto Hornero, Miguel López

Department of Signal Theory and Communications, University of Valladolid, Campus Miguel Delibes, Valladolid, Spain

María Isabel López

University Institute of Applied Ophthalmobiology (IOBA), University of Valladolid

Edificio Ciencias de la Salud, Valladolid, Spain

Keywords: Clinical Document Architecture (CDA), Digital Imaging and Communications in Medicine (DICOM),

Electronic Health Record (EHR), Extensible Markup Language (XML), Health Level 7 (HL7), Java.

Abstract: Electronic Health Record (EHR) refers to the complete set of information that resides in electronic form and

is related to the past, present and future health status. Health Level Seven (HL7) and Digital Imaging and

Communications in Medicine (DICOM) are intensively influencing EHRs standardization. This article

describes the development, experience and evaluation of a web-based application, TeleOftalWeb 3.2, to

store and exchange EHRs in ophthalmology. We apply HL7 Clinical Document Architecture (CDA) and

DICOM standards. EHRs and fundus photographs are stored in a database Oracle 10g. The application has

been built on Java Servlet and Java Server Pages (JSP) technologies. For security, all data transmissions

were carried over encrypted Internet connections such as Secure Sockets Layer (SSL) and HyperText

Transfer Protocol over SSL (HTTPS). The application verifies the standards related to privacy and

confidentiality. TeleOftalWeb 3.2 has been tested by ophthalmologists from the University Institute of

Applied Ophthalmobiology (IOBA), Spain. Nowadays, more than one thousand health records have been

included to verify the web application usability.

1 INTRODUCTION

Electronic Health Records (EHRs) are a secure, real-

time, point-of-care and patient-centric information

resource for physicians (HIMSS, 2003). EHRs

include information such as observations, laboratory

tests, diagnostic imaging reports, treatments,

therapies, drugs administered, patient identifying

information, legal permissions and allergies.

Currently, this information is stored in all kinds of

proprietary formats through a multitude of medical

information systems available on the market

(Eichelberg et al., 2005). EHR systems can

incorporate clinically useful features such as

electronic alerts, guideline reminders and automatic

monitoring of quality of care indicators (Bostrom et

al., 2006). The primary purpose of EHR is the

support of continuing, efficient and quality

integrated health care. Amongst EHRs benefits are

their universal access, coding efficiency and

efficacy, easier and quicker navigation through the

patient record (Smith and Newell, 2002). There are

several barriers to their adoption such as training,

costs, complexity and lack of a national standard for

interoperability (Gans et al., 2006).

Ophthalmology is an ideal specialty for testing

EHRs due to the use of images and objective

measures during diagnosis of eye diseases. It is an

ideal speciality for telemedicine. EHRs systems can

assist ophthalmologists in improving the quality of

care being provided as well as assist the

ophthalmologists in building solid relationships with

their patients. Physicians who have shared EHRs

available yet fail to consult them before beginning

treatment could face increasing liability in the future

(Yogesan et al., 1998).

International and European institutions are

working in EHR standardization such as the

International Standards Organization Health

Informatics Standards Technical Committee

de la Torre I., Hornero R., López M. and López M. (2009).

OPHTHALMOLOGIC ELECTRONIC HEALTH RECORDS SYSTEM USING HL7/CDA AND DICOM - TELEOFTALWEB.

In Proceedings of the International Conference on Health Informatics, pages 99-104

DOI: 10.5220/0001120500990104

 SciTePress

(ISO/TC) 215, European Committee for

Standardization Technical Committee (CEN/TC)

251, Health Level Seven (HL7), Extensible Markup

Language (XML), Digital Imaging and

Communication in Medicine (DICOM) and others

(Bott, 2004). The development of HL7 and DICOM

standards has also been of great benefit in the

telemedicine services and applications.

HL7 standard is used for many different medical

environments. It is a not-for-profit organization

involved in development of international healthcare

standards. HL7 Document is intended to be the basic

unit of a document-oriented EPR. The patient

medical record is represented as a collection of

documents. HL7 Clinical Document Architecture

(CDA) is a XML-based document markup standard

that specifies the structure and semantics of EHR for

the purpose of exchange. Clinical Document

Architecture – Release One (CDA–R1), became an

American National Standards Institute (ANSI)–

approved HL7 Standard in November 2000,

representing the first specification derived from the

HL7 Reference Information Model (RIM). CDA –

Release Two (CDA–R2), became an ANSI-

approved HL7 Standard in May 2005 (Dolin et al.

2006). CDA standard provides an exchange model

for clinical documents. Many CDA documents

comprise an individual EHR.

DICOM is a cooperative standard. It was

developed from 1990 to 1996, mainly by the

American College of Radiology (ACR) and National

Electrical Manufacturers Association (NEMA)

committee in the United States, with contributions

from European standardization organizations, the

Japanese Industry Radiology Apparatus (JIRA), the

Institute of Electrical and Electronics Engineers

(IEEE), HL7 and ANSI as well as from European

manufacturers and societies. This standard allows

the exchange of medical images and related

information between systems from different

manufacturers.

EHRs have a great potential to improve

safety,

quality and efficiency in medicine. EHRs systems

often involve many institutions. Most previous

studies addressing this issue have been done in

primary care (Lo et al., 2007). In our application,

EHRs are shared between ophthalmologists,

endocrinologists, and primary care physicians.

We reviewed articles about EHR systems in

different specialities such as pediatric (Ginsburg,

2007), emergency departments (Amouh et al.,

2007), ophthalmology (Chew et al., 1998) and

oncology (James et al., 2001). In these systems,

HER standardization applying HL7/CDA and

DICOM was not presented.

We have designed, developed and evaluated a

web-based application to store and exchange EHRs

in ophthalmology, TeleOftalWeb 3.2. We apply

HL7/CDA and DICOM standards. The application

has been built on Java Servlet and Java Server Pages

(JSP) technologies. EHRs and fundus photographs

are stored in Oracle 10 g database. Its architecture is

triple-layered. The application server is Tomcat

5.5.9. The application is platform-independent

thanks to using Extensible Markup Language

(XML) and Java technologies. For security, all data

transmissions were carried over encrypted Internet

connections such as Secure Sockets Layer (SSL) and

HyperText Transfer Protocol over SSL (HTTPS).

The application verifies the standards related to

privacy and confidentiality. It has been tested by

ophthalmologists from the University Institute of

Applied Ophthalmobiology (IOBA), Spain.

Currently, more than one thousand health records

have been included.

2 METHODS

Firstly, we describe the application data modeling in

Oracle 10g database. Then, we show the application

architecture.

2.1 Data Modeling

In Oracle 10g database, we stored all the user data

and access information to the web application. It has

three tables: “users”, “permissions” and “records”.

The table “users” contains personal user data. The

user identification, user name, password, and user

type appear in table “permissions”.

EHRs are stored in Oracle 10g database

according to the ANSI/HL7 CDA R2.0-2005

template. The data modeling in the Oracle database

is shown in Figure 1.

Oracle 10g introduced a new datatype,

XMLType, to facilitate native handling of XML

data in the database. It supports comprehensive

models (i.e., structured, unstructured and binary

XML storage models) to server diverse XML use

cases with different requirements. For table

“records” (see Figure 1), we use this datatype.

XMLType is stored in Large Objects (LOBs). LOB

storage maintains content accuracy to the original

XML (whitespaces and all). When we create an

XMLType column without any XML schema

specification, a hidden CLOB column is

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automatically created to store the XML data. The

XMLType column itself becomes a virtual column

over this hidden CLOB column. It is not possible to

directly access the CLOB column.

Oracle XML database provides efficient support of

SQL/XML XMLTable function and its COLUMNS

clause for mapping XML data into relational views.

By taking advantage of XQuery rewrite technology,

storage models, indexing schemes, downstream

processing on a relational view created with

XMLTable function can approach pure-relational-

performance (Oracle, 2008).

2.2 Application Architecture

TeleOftalWeb 3.2 architecture is a triple-layered.

Oracle 10g is used as database server and Apache

Tomcat 5.5 as application server. Figure 2 shows the

application architecture. Oracle 10g provides high-

performance, native XML storage and retrieval

technology.

We employ an Oracle Java Database Connectivity

(JDBC) driver to connect to the database instance. A

free open-source application server to process the

requests is used. The web-based system was built on

Java Servlet and JSP technologies, which enables

rapid development of web-based applications. In

Oracle database, we stored all the user data, access

information to the web application and records with

fundus photographs.

The development environment was NetBeans

IDE 4.1 of Sun Microsystems. The application is

platform-independent thanks to using XML and Java

Technologies. Java was the basis application

programming language. XML is an open standard

that provides a unified model for data, content and

metadata. It is being used to manage mission critical

information.

We included all tools and Application

Programming Interface (API) as Javascript, JSP,

Java Servlets and JDBC. The evolution of Java

Technology brings more features to the Java

development tools. This facilitates the creation of

telemedicine applications and reduces the time of

developing programs (Fedyukin et al., 2002). XML

technology is employed to store and exchange

EHRs. Some XML advantages are: easily readable,

self-describing and interoperable.

Figure 1: Data Modeling.

Figure 1: Application Architecture with Oracle 10g.

Figure 2: Architecture Application with Oracle 10g.

CDA Release 2 model is richly expressive,

enabling the formal representation of clinical

statements (such as observations, medication

administrations and adverse events) such that they

can be interpreted and acted upon by a computer

(Dolin et al., 2006).

As it was indicated in the introduction, CDA

documents are encoded in XML. The CDA is only

the first example of HL7's commitment to the

advancement of XML-based e-healthcare

technologies within the clinical, patient care domain.

The CDA specification prescribes XML markup for

CDA Documents: CDA instances must be validated

against the CDA Schema and may be subject to

additional validation. The document can be sent

inside or outside a HL7 message. CDA also supports

the semantically interoperable exchange of complex

medical information between healthcare applications

by virtue of its adherence to the HL7 V3

development methodology (Chronaki et al., 2002).

CDA does not specify the creation or management

of documents, only their exchange mark-up.

The XML-based architecture described in the

CDA v2.0 standard has been used to define the

health information format. Thanks to the use of

XML-based technologies and HL7 specifications,

our application fulfils the EHR standards. Its

development methodology is a continuously

evolving process that seeks to carry out

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specifications that facilitate interoperability between

healthcare systems.

3 RESULTS

We present the two application modules: manager

and user. Then, we describe the experience of

introducing diabetic patient’s health records from a

screening program of diabetic retinopathy in a rural

area of Spain (Hornero et al., 2003).

3.1 Manager Module

The manager can access the web platform with any

browser. Login and password have to be introduced

by users. The two user roles are: manager and user.

Application manager allows to:

 Create new users.

 Show user information.

 Erase users.

 Modify physician’s information.

 Show user statistics.

 Show the user patient records.

 Search users by different criteria such as

surname, identification number, type of user,

and member number.

3.2 User Module

The authorized physicians can access to this module.

They have their login and password. They can do

the following actions:

 Create new records (see Figure 3). They have

to introduce the necessary data: patient

affiliation information, patient precedents,

medical exploration and diagnostic.

 Erase records and revisions.

 Create new revisions in a record.

 Search different EHRs and revisions,

 Add new images in different records.

Physicians can add new images in an EHR.

These may be in different formats such as

DICOM, Joint Photographic Experts Group

(JPEG), Graphics Interchange Format (GIF),

DIB file format (BMP), Tagged Image File

Format (TIFF) amongst others.

 Search images according to different criteria:

image identification number, surnames, image

creation and comments.

Figure 3: Exploration in a new EHR.

Figure 4: DICOM fundus photograph.

 Edit and erase images. The images editor (see

Figure 4) shows images and allows us to

change their shape and colour, zoom in or

zoom out. It supports image editing of

brightness and contrast. Other editor functions

are: RGB (Red, Green, Blue) scale, add and

delete text, and arrows. It supports all type of

images (DICOM, JPEG, GIF, etc.).

 Print EHRs in Portable Document Format

(PDF). We employ Extensible Stylesheet

Language Formatting Objects (XSL-FO) to

format XML data. XSL-FO is a complete

XML vocabulary for laying out text on a page.

An XSL-FO document is a well-formed XML

document that uses this vocabulary. EHR

output format is a PDF. First, the XML must

be fed to an XSLT processor with an

appropriate stylesheet in order to produce

another XML document which uses the XSL-

FO namespace. It is intended for an XSL-FO

formatter. The second stage is to feed the

output of the first stage to the XSL-FO

formatter that can produce a printable

document styled for visual presentation

(Pawson, 2002).

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3.3 Practice Case

TeleOftalWeb 3.2 has been tested by physicians

from the University Institute of Applied

Ophthalmobiology (IOBA), Spain. Nowadays, more

than one thousand health records were introduced.

All the patients were diabetic and they participated

in a telemedicine program for diabetic retinopathy

screening in a rural area of Spain (Hornero et al.,

2003). Diabetic retinopathy is the most common

diabetic eye disease and a leading cause of blindness

in adults. It is caused by changes in the blood

vessels of the retina (National Eye Institute, 2008).

Our application allows to store and exchange all the

records and fundus photographs. Physicians used the

application with different web browsers to store and

exchange the EHRs. In each record there are the

following parts: anamnesis, exploration, diagnosis

and treatment. The EHR is associated with the

fundus photographs in all type of digital formats.

A survey with ten questions about the application

usability was done (see Figure 5). We used System

Usability Scale (SUS) to make the questionnaires. It

is a Likert scale. SUS has proved to be a valuable

evaluation tool, being robust and, reliable. It

correlates well with other subjectives measures of

usability (Brooke, 1996). Six physicians used the

application. The SUS score is major than fifty for all

the physicians. Its average value is seventy four. The

questions such as: clinical records are organised and

legible, access to EHRs from any place, information

quality in the application were strongly agreed. The

results can be viewed in Table I. According to these

results, our web-based application is useful for the

physicians because SUS score is always major than

50.

4 CONCLUSIONS

In this study, a web-based application has been

developed to store and exchange EHRs and fundus

photographs in Ophthalmology by using HL7/CDA

and DICOM standards. EHRs have several distinct

advantages and disadvantages over paper health

records. One advantage is the fact that there are

increased storage capabilities for longer periods of

time. EHRs can also provide medical alerts and

reminders. Some of the disadvantages include such

items as the startup costs, which can be excessive.

Another disadvantage to an EHR is that there is a

substantial learning curve and it is helpful when the

users have some type of technical knowledge

(Gurley, 2004).

Table 1: Satisfaction survey results.

Questions Physicians

1 2 3 4 5 6

1 4 4 4 4 4 4

2 3 4 4 3 4 4

3 3 4 4 4 3 3

4 3 3 3 4 3 3

5 4 3 3 3 4 4

6 4 4 4 4 4 4

7 4 4 4 4 4 2

8 2 2 1 2 2 4

9 2 2 2 2 2 2

10 4 4 3 4 4 4

SUS Score 67,5 75 67,5 80 80 75

Figure 5: Users satisfaction survey.

TeleOftalWeb 3.2 advantages are: its adaptation

to the HL7/CDA and DICOM standards, the

interoperability facilitation between institutions and

applications and its security. The physicians can

analyze EHRs everywhere. The application verifies

the standards related to privacy and confidentiality.

However, the application speed depends mainly on

the Internet connection and the number of users in

the system. When this number is high, the

application speed is lower.

DICOM and HL7 are well-accepted healthcare

industry standard. DICOM is used in diferent

medical fields, such as pathology, endoscopy,

dentistry, ophthalmology and dermatology. It is a

success for radiology and cardiology, and it is now

beginning to be used for other clinical specialties

(Kuzmak and Dayhoff, 2003).

According to our review, we analyzed several

studies about EHR systems. These systems have

been presented using XML-based Clinical

Document Architecture to exchange discharge

summaries (Paterson et al., 2002). There are EHR

applications in different specialities such as pediatric

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(Ginsburg, 2007), ophthalmology (Chew et al.,

1998), emergency departments (Amouh et al., 2007)

and oncology (James et al., 2001). In the telematic

system for oncology, they use a data warehouse as

EPRs server. The authors do not present a EHRs

standardization process. Information system for

emergency department has been implemented by

prototyping a web-based application. It makes uses

the XML-based openEHR standard.

In summary, we have designed, developed and

evaluated a web-based application to store and share

EHRs in ophthalmology by using HL7/CDA and

DICOM standards. Our application treats to solve

some of the barriers to the EHRs adoption in

ophthalmology. The records and the fundus

photographs in all type of formats are continuously

updated and are available concurrently for use

everywhere. We verified that the application was

useful for the physicians.

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