EUROGRAPHICS 2007 / P. Cignoni and J. Sochor

Short Papers

A Pen-based Interface for Generating Graphical Reports ofFindings in Cardiac Catheterization
Yuki Mori1

Takeo Igarashi1

Ryo Haraguchi2

Kazuo Nakazawa2

1 The University of Tokyo, Japan 2 National Cardiovascular Center Research Institute, Japan

Abstract
This paper introduces a pen-based interface for the graphical reporting of findings in cardiac catheterization. The
user can interactively draw, erase, move, and deform coronary arteries as well as record stenoses on them. Thelo-cation and degree of each stenosis is represented visually and the doctor can record various treatments such as
by-passes and stents on the diagram. In addition, the system automatically extracts semantic information from thegraphical representation and stores it in XML format. The system can also generate a table in the format specified
by the American Heart Association. This system is useful not only as a tool for efficiently generating reports offindings but also as an effective explanation tool for patients.
Categories and Subject Descriptors (according to ACM CCS): I.3.6 [Computer Graphics]: Methodology and Techniques

1. Introduction
Electronic medical recording systems [GIN07] have become
widespread due to the improvement in hardware performance and user interfaces. However, usability is still an issue
and medical professionals need more such user-friendly interfaces. To make these systems accessible to inexperienced
users and to reduce the overhead of data entry, we have beendeveloping various pen-based elec-tronic medical recording
systems. Pen-based computing is an active research area forboth user interfaces and com-puter graphics. One problem
with these free-form pen-based systems, however, is that
their output does not easily fit into a structure that lends itself to further machine proc-essing or interface with othermore traditional recording systems. Our goal in the project
presented in this paper was to bridge this gap between freeform diagramming and more structured recording.
One strength of pen-based systems is that they make iteasy to draw and add diagrams to medical records. This isparticularly useful in ophthalmology, otolaryngology, anddentistry in which diagrams play an important role in medical records. Indeed, the frequent use of diagrams makes it
difficult to use traditional GUI-based medical recording systems in these areas. Cardiac catheterization is one of theseareas in which the diagram is an indispensable tool for medical recording. Existing electronic medical recording systems
c The Eurographics Association 2007.

rely on structured templates, but it is difficult to create an
appropriate report of findings or treatment plan using thesepredefined templates. Most ex-isting diagram editors are implemented as bitmap paint tools, not vector graphics. This
makes it difficult to edit the geometry afterward and requiresthat a large amount of data be transmitted and stored.

Figure 1: A screenshot of our system in use.

Y. Mori et al. / A Pen-based Interface for Generating Graphical Reports of Findings in Cardiac Catheterization

We therefore developed a pen-based interface for graphical reporting of findings in cardiac catheterization (Figure 1).
The user can freely "sketch" coronary arteries and stenoses
on the screen using a pen on a template of coro-nary features.
The location and degree of each stenosis, and various treatments such as bypass and stents, are visually represented.
We developed an algorithm that can extract semantic information from the graphical representation and store it in XMLformat. The system can also generate a table in the format
specified in the AHA (American Heart Association) committee report [AEF∗ 75]. This system is useful not only as atool for efficiently generating reports of findings but also as
an effective explanation tool for patients.

draw a new coronary artery

pull a coronary arterymove a coronary arterysmooth a coronary artery

Figure 3: Editing operation of a coronary artery. We use apulling interface and smoothing interface for curves introduced in [IMH05].

2. User Interface
Figure 2 shows screen snapshots of our system. The user candraw on the diagram template using a pen as if drawing onreal paper. Our system shows the name of each coro-naryartery and segment (e.g., proximal, middle, or distal) at theupper right of the screen when the cursor is over any vessel.
We use the naming scheme defined in the AHA committee
report. The system can show border lines of coronary arterysegments if required. The user can freely sketch coronary arteries (Figure 3) and stenoses (Figure 4) on the screen template. The location and degree of each steno-sis, and various
treatments such as bypass and stents are visually represented
on the screen (Figure 5). The diagrams use vector graphics
for easier editing of the input, as well as for reducing requirements in data storage and transmis-sion bandwidth.

Figure 4: Recording a stenosis.

dataset. The table is represented in the format speci-fied in
the AHA committee report and stored as an XML file. Figure 6 shows the relationship between our system and CAG.
The top screen in Figure 6(a) presents an example of recording stenoses using our system; the middle screen of Figure6(a) shows the CAG dataset it produces. Any other systemthat supports this format can use the data file as shown inthe bottom screen of Figure 6(a). The user can also edit theexported CAG table. When this happens, our system automatically updates the corre-sponding stenosis on the coronary diagram including the information on the severity andcharacter of the stenosis (Figure 6(b)).

Figure 2: Recording example of cardiac catheterization.

3. Dataset Structure and Cooperation with OtherSys-tems
Many doctors use coronary angiography (CAG) to repre-sentcoronary stenosis pathology. CAG compactly shows the location and severity of stenoses. Our system supports the conversion of the graphical record to a CAG-compliant table

(a)

(b)

Figure 5: Drawing a bypass. If the bypass connects anopen coronary artery to a closed one (a), the system automatically opens the closed coronary artery to indicate thatblood flow has resumed (b).

c The Eurographics Association 2007.

Y. Mori et al. / A Pen-based Interface for Generating Graphical Reports of Findings in Cardiac Catheterization(a)(b)

Figure 6: Example of the automatic relationship between
the coronary diagram and the CAG table.

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[IMH05] IGARASHI T., MOSCOVICH T., HUGHES
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c The Eurographics Association 2007.