Chapter 16: Standardization of the Endoscopic Report 191
congested mucosa. Therefore, these words could be used
as an alternative but not added simultaneously to the
number of terms used.
• Erosion, aphtha are frequently used to describe similar
lesions. In the original OMED terminology, the term
erosion had been avoided because it was considered to be
the aortic prominence, the term “stenosis” should not
be used.
• Red mucosa, erythema, congested mucosa, hyperemia were
used to define roughly similar lesions or mucosal pat-
terns. Instead of these ambiguous terms, two terms were
selected: erythematous mucosa, defined as either a focal
or diffuse reddening of the mucosa without any other
modification, and congested mucosa, defined as a com-
bination of erythema with an edematous, swollen or fri-
able mucosa (Fig. 16.6). Due to the large overlap between
these terms, it was agreed that hyperemia was equi-
valent to erythema and edematous was equivalent to
Fig. 16.5 Example of colonic stenosis from a benign process
(a) or a malignant process (b).
Fig. 16.6 Erythematous mucosa in the colon, defined as an
increased redness of the mucosa, due to an increase in its
hemoglobin content because of increased blood flow (a). This
should be distinguished from a congested mucosa, defined
as a swelling of the mucosa due to an increase in the thickness
of the mucosa, occurring most often in association with an
inflammatory process where permeability of cell membranes is
altered and the extracellular osmolarity is modified (b).
(a)
(b)

are frequently seen within a congested or erythematous
mucosa and are often multiple (Fig. 16.7).
• Tumor, mass are regarded as synonyms that comply
with local habits in some parts of the world. The word
tumor is preferred to describe any lesion which appears
to be of a neoplastic nature but without any attempt to
say whether it is benign or malignant. It is not used for
small lesions such as granules, papules, etc , nor for
other protruding lesions such as polyps, varices, or giant
folds. The conjoint ASGE review had difficulty with this
term as, in the USA, a patient might assume that a tumor
is a malignant lesion. For this reason, it has been agreed
that the term mass could be used as an equivalent term
when needed.
• Angioectasia has been selected as a generic term
encompassing both telangiectasia and angiodysplasia.
This is because there are no precise visible diagnostic
criteria that will allow one to distinguish between these
two lesions. This term can also be applied to congenital
and acquired vascular malformations within the mucosa
of the gastrointestinal tract.
• Scar is preferred to the term fibrosis as the latter
implies a histologically confirmed process. The cicatri-
cial aspect of the mucosa after healing of an ulcer or fol-
lowing a therapeutic maneuver (e.g. injection sclerosis,
laser photocoagulation) seems to fit better with this
word.
• Occlusion, obstruction, although frequently regarded
as synonyms, should be used more distinctly, as obstruc-
tion means blockage of a tubular structure by an intralu-

use in natural language into the elemental data of an
MST-driven report. MST has designed the nomenclature
based on data models that will meet the actual situations
where the users are working.
Fig. 16.8 Example of an ulcerated mucosa (a) involving the
rectum in a patient with ulcerative colitis. An ulcerated
mucosa does not necessarily lead to that diagnosis and this
term should not be used in the presence of multiple well-
delineated ulcers, separated by areas of almost normal
mucosa (b).
Validation of the Minimal Standard Terminology
Valiadation of the MST has been performed in two
multicenter studies, one undertaken in Europe and
one in the USA [11,12]. Six thousand two hundred
and thirty-two reports were analysed, including 1743
colonoscopies in the European study [11]. Overall, terms
originally contained in the MST could describe fully
91.0% of all examinations where “reasons for” were
described, 99.5% of examinations where “findings” were
described, 95.8% of all examinations containing descrip-
tions of “endoscopic diagnosis,” 98.9% of examinations
containing descriptions of “additional diagnostic proced-
ures,” and 94.8% of examinations containing descrip-
Table 16.4 Results of the testing in the US MST Lexicon Testing Project: total number of examinations and findings.
Number of Number of Number of findings % findings
Examination type examinations abnormal findings described with MST described with MST
All 17 426 33 115 31 079 94
EGD 8136 20 310 19 030 94
Colonoscopy 8296 11 310 10 614 94
ERCP 994 1495 1435 96

of the diseases. All these actions require an integration of
medical data, initially at the level of each specialty but
also as exported of data from the specialized unit, (i.e.
the endoscopy unit) to the integrated care unit through
the hospital information system. Large standardized
systems have failed in the past to cover the whole range
of medical data. This justifies the use of SNOMED to
attempt validation of microglossaries in specialty related
domains and to integrate these microglossaries at a high
level, making them intermeshed by a common structure
[15].
Future trends and maintenance of the Minimal
Standard Terminology
The future is represented by two main lines of actions:
one will be devoted to the maintenance of the MST with
respect to evolution of knowledge and practice and to its
preservation from inconsistent changes during wider
use. The second line will ensure the flexibility of the MST
and its possible adaptation to specific situations.
Maintenance of the MST is a longstanding activity that
must be integrated in the frame of a scientific society, but
it must be an open process that will ensure responsive-
ness to new developments. Recently, the representatives
of OMED, ESGE, and ASGE have met and decided, with
the cooperation of some Japanese colleagues, to set up
an editorial board for the MST. This board will have
The modeling of a structured language as a basis
for standardization
An endoscopy report can be thought of as a file which
contains a series of documents defined by the needs of

retrieved from databases because relational databases
currently used in medical informatics are more and more
built as “object-oriented” databases. Another advantage
of this database architecture is that data can be retrieved
as structured subsets in a fast and secure process.
Clinical benefits for the use of a structured language
Although the advances in endoscope technology have
allowed the production of high-quality video images to
be transmitted, captured and stored by modern high-
speed integrated circuits, image documentation and
reporting has not progressed so fast. However the con-
stant increase in the use of computers for the manage-
ment of medical data has induced a strong need for the
standardization of the data to be exchanged. Standard-
ization means the coding of the data in a common for-
mat that can be read by multiple information systems,
operated on different platforms. This goal is achieved by
actions like the DICOM or HL-7, but goes far beyond
Chapter 16: Standardization of the Endoscopic Report 195
images from a video signal stream of voltage changes,
measured every few microseconds, to turn the continu-
ous signal into a discrete one. This procedure is called
sampling. At the same time, the computer quantifies
each of the measured values into a numerical value, to
turn the analog signal into a digital one. These two pro-
cesses, sampling and quantifying, transform the continu-
ous analog signal into a discrete digital signal, which can
then be stored in the memory of the frame grabber
board. The accuracy of the digitization process depends
on the frequency of the measurement and the maximum

of video signals through wires, but not on the resolution
of the frame-grabber board. The file size of an uncom-
pressed image depends on the area in pixels multi-
plied with the color depth, for example 400 × 400 × 24 =
3 840 000 bits. The usual unit for file sizes in a computer
is Byte, and 1 Byte equals 8 bits. In our example, the
image of 3 840 000 bits would take 480 000 Bytes, or if we
divide the number of bits by 1024, the file size is con-
verted to kiloBytes (also kByte or KB). In this example,
the file size is then 468.75 kBytes. Using compression
algorithms, the size can be reduced by the factor 2–
10, without any or significant loss of image quality,
depending on the compression method. For instance,
the compression type that can be selected is based on
the compression algorithm that was initially developed
by the Joint Photographers Expert Group (JPEG) [17],
an international dimension and will care for the tasks
related to MST, in close cooperation with the various sci-
entific societies. The MST editorial board will be respons-
ible for the maintenance of the subsequent versions of
MST, the adaptation of it to new practice, and the release
of these versions. The main task of the board will be to
promote the use of the MST and to establish relation-
ships with the national societies for gastrointestinal endo-
scopy, supporting the production of accurate translation
in the national languages and the organization of educa-
tional events to teach the community how to use MST.
Moreover, the editorial board will have to disseminate
the MST amongst software developers and to encourage
them to implement it in their applications. The editorial

quickly been extended to other modalities producing
images in visible light (VL) like ophthalmology, dentistry,
and pathology [16].
Production of digital endoscopic images
Only electronic video endoscopes provide endoscopic
images of high resolution that support digitization and
use in computers. Video endoscopes create analog
196 Section 4: Reports and Imaging
• creation of diagnostic information databases that can
be interrogated by a wide variety of devices geographic-
ally distributed.
To achieve these goals, the DICOM standard organizes
the data describing each image and the text data of the
examination to which it belongs into an entity that is
called an object (see above). This object is made of vari-
ous data that are each identified with a specific header
telling the computer what kind of data is stored. Data are
organized in three levels, depending on their importance
for a proper reading of the file. Mandatory data are those
that need to be present for any image, for example the
content of each pixel that composes the image or the total
number of pixels. Conditional data are required only in
some circumstances, for example the name of the patient
or his/her identifier in the hospital information system
that are required only when a nominative report needs
to be created. Optional data are regarded as not neces-
sary for the accurate transfer of the data and left to the
particular requirements of a given application, for ex-
ample the patient’s address and insurance numbers will
only be used in specific applications but are not part of

Management of endoscopic images in
computer systems
When an image has been captured by the frame-grabber
board, it must be transferred to the storage device where
it will be hosted. To save the image information, it is
transferred from the frame-grabber card through the bus
of the computer system to its RAM (the operating mem-
ory of the computer) and from there to storage on mass
media, for example floppy disks, hard disks, magneto-
optical disks, or CD-ROM/DVD media (Fig. 16.9).
Transfer of endoscopic images with the
DICOM protocol
The DICOM protocol organizes the transfer of images
between computers based on different operating sys-
tems. Thereby, the DICOM protocol ensures the follow-
ing features [6]:
• promotion of communication of digital image infor-
mation, regardless of equipment and/or manufacturer
producing this image;
• facilitation of the development and expansion of pic-
ture archiving and communication systems (PACS) that
can also interface with other systems within the HIS;
Fig. 16.9 Process of digitization of
endoscopic images in an endoscopic
workstation including an electronic
videoendoscope and a computer
equipped with a frame grabber card
for capture of images. This computer
can be further linked to the hospital
network to make the images captured

the application generating the images or displaying
them is strongly decoupled from the communication
process, which coordinates data transmission between
systems and compensates for the different ways in
which data are internally represented on different sys-
tems (Fig. 16.10). Hence, the role of each system must be
clearly defined. The most important distinction is the
one defining the role of “server,” i.e. the application that
offers functionalities to others, and the role of “client,”
i.e. the application that uses the functionalities gener-
ated by others. These relationships are managed under
the TCP/IP protocol that basically organizes relation-
ships between servers and clients, for example on the
Internet. Once the roles have been defined, the sys-
tems must organize the information they want to share.
This information is defined by the context of the service
implemented. In our example, the storage of images
in large reference databases will not require the same
information as the display of the image in the clinical
unit. However, if the clinical unit wants to retrieve
images from the large database, the information used by
each of these processes must be consistent and this is
achieved by the definition of a global context to which
each process will refer to organize information.
Hospital information System
Report
Endoscopic Information System
Remote access to
medical data
Educational applications

computers. The data generated during an endoscopy
procedure include images and text. The rapid growth of
computers for data management in medicine requires
that these data be stored in standard formats which are
the basis for a proper exchange of information between
systems.
References
1 Delvaux M, Escourrou J. Image management. The point of
view of the physician. Endoscopy 1992; 24: 511–15.
2 Liebermann DA, de Garmo PL, Fleischer DE, Eisen GM,
Chan BKS, Helfand M. Colonic neoplasia in patients with
nonspecific GI symptoms. Gastrointest Endosc 2000; 51: 647–51.
3 Kruss DM. The ASGE database: computers in the endo-
scopy unit. Endosc Rev 1987; 4: 64–70.
4 Delvaux M, Crespi M and the Computer Committee of
ESGE. Minimal Standard Terminology in Digestive
Endoscopy. Version 2.0 Endoscopy 2000; 32: 159–88.
5 Maratka Z. Terminology, Definitions and Diagnostic Criteria
in Digestive Endoscopy, 3rd edn. Bad Homburg: Normed
Verlag, 1994.
6 Digital Imaging and Communication In Medicine (DICOM),
NEMA PS3.1–PS3.12. Rosslyn, VA: The National Electrical
Manufacturers Association, 1992, 1993, 1995, 1997.
7 Computer Committee. Standard Format and Content of the
Endoscopic Procedure Report. American Society for Gastro-
intestinal Endoscopy, 1992.
8 Delvaux M. Image management: the viewpoint of the
clinician. Gastroenterologist 1996; 4: 3–5.
9 Fujino MA, Morozumi A, Nakamura T et al. Electronic
endoscopy in perspective. J Gastroentero, 1994; 29: 85–90.

provider. However, the service user or client must be
able to recognize this syntax.
Although the general principles of the DICOM can
be quite easily understood, the implementation in data
management systems has been delayed because of the
complexity of the data to be managed and the difficulty
in creating the link between the various systems. These
problems have recently been solved with the develop-
ment of Internet technology and the use of the XML lan-
guage. In that format, data are described in a Definition
Type Document (DTD) that describes all the data ele-
ments that are needed for a specific action or service. The
DTD is an easier way of organizing the data elements
contained in the IOD (see above).
Use of endoscopic images in clinical practice
Various scenarios have been investigated for the clinical
use of digitized endoscopic images. The obvious advant-
age is the production of a complete endoscopic report
associating text data and images. Insertion of images in
the endoscopic report supposes that it will be produced
by a computerized report generator. Moreover, this
report must be transferable to the hospital information
system to be included in the patient file that is contained
in the database of the hospital information system.
Production of computerized endoscopic reports will
also foster several clinical applications, including out-
come studies, quality assurance processes, and large
multicenter trials. Such achievements will become suc-
cessful when endoscopic manufacturers and software
developers integrate computers and electronic endo-

the report should be listed in each copy of the report.
This is important for ensuring that all the units involved
with the patient know who received the pertinent
information and, even more importantly, who did not.
This is a vital step in avoiding patients becoming lost to
follow-up.
Endoscopist
The attending and fellow endoscopist, as well as other
doctors attending the procedure, should be included in
the report. Even though the fellow typically formulates
the report, it is usually important for the reader to realize
who was responsible for the interpretations and recom-
mendations presented. In a complex case where the sur-
geon and possibly the radiologist are summoned, this
information should be included as well; alternatively,
this information can be detailed in the interpretation/
conclusion part of the report.
Indication/clinical history
The reason for the procedure should be clearly stated in
the report. This may be a suspected illness, work-up of
a specific symptom, follow-up of a known disease with
or without sampling, or screening purposes. There is a
subtle difference between indication and reason for the
procedure, since indications may have implications for
Introduction
Gastrointestinal endoscopy is a visual clinical discipline.
All examinations, findings, descriptions, and recom-
mendations are based on the images created during the
endoscopic examination. In interventional work, the
images are the sole guiding material for correct pro-

a certain general structure prevails in most centers, and
the ensuing elements and the description thereof is
endorsed by a majority of the endoscopic community.
Chapter 17
Reporting and Image Management
Lars Aabakken
Colonoscopy Principles and Practice
Edited by Jerome D. Waye, Douglas K. Rex, Christopher B. Williams
Copyright © 2003 Blackwell Publishing Ltd
200 Section 4: Reports and Imaging
noted to enable a more specific repeat study. The com-
pleteness of the endoscopy is recorded, including any
uncertainty about it and the reason for incomplete study.
Even the choice not to enter the distal ileum should be
noted; the reason may be perfectly valid (polyp screen-
ing). In the case of particular difficulties in passing the
instrument, the specific solutions should be included in
the report. It is possible that these solutions may need to
be repeated at a later date.
Findings
The description of findings is the core information of the
report. An objective, systematic, and detailed account of
what was seen, or not seen, is the main result of your
procedure. This may sound simple but there are caveats.
1 Findings should be described completely and object-
ively, based on features that are visualized not inter-
preted. To achieve this, a standardized terminology is an
excellent tool (described later). Mixing objective features
and interpretation is very easily done, but all interpretat-
ive comments should be reserved for the Impression

reimbursement. A reason for a procedure, on the other
hand, has both clinical and practical implications.
In this section, a concise clinical history is also of
value. It serves to put the endoscopic procedure and
findings in a context even for readers unfamiliar with the
specific patient. There is no need for a complete medical
history, but issues of relevance to the endoscopy are
important. This includes symptoms/signs and previous
work-up of the disease in question. It also includes other
diagnoses or problems that are of potential relevance to
the endoscopy, e.g. in the context of possible complica-
tions. Diabetes, cardiopulmonary problems, anxiety dis-
orders, and hemorrhagic diathesis are a few examples of
possibly relevant diagnoses that can be explicitly stated
as part of the endoscopy report or reported in a separate
history section. This will show the reader that the pro-
cedure was done only after a thorough evaluation of all
aspects of the particular patient.
Informed consent/disclaimer
The endoscopy report should state that information
about the procedure was given to the patient and, to
some extent, what that information was. In many
countries written informed consent is required prior
to the procedure and referral to such a document
will be sufficient. Most lawsuits after mishaps are
based on the patient’s perceived lack of information
of possible complications, and written documentation
is vital to document the standard of care. In special
cases, e.g. a high-risk dilation procedure, a specific
account of the discussion with the patient is even more

Endoscopists had little or no means of communicating
what they saw, apart from the written endoscopy report,
which was an interpretation of the images. Twin eye-
pieces and mountable cameras were steps in the right
direction, allowing discussion and exchange of image
information, but these were cumbersome gadgets with
limited dissemination.
The introduction of video-based imaging systems
created a host of new opportunities. The eyepiece was
replaced with the greatly enhanced viewing experience
of a large monitor screen, enabling the endoscopic exam-
ination to become a shared experience with colleagues
and assistants. In addition, still image printers could be
connected for paper prints of important findings.
The video signals received and processed in the
endoscopy equipment can also be stored electronically,
as captured electronic images or digital video. In com-
bination with other existing technologies, this enables
access and use of endoscopic images far beyond what
was previously feasible.
The increasing availability of electronic image cap-
turing systems opened up new ways of documenting
procedures. Where the reader was previously confined
to the endoscopist’s concept of a “large ulcer”, “profuse
bleeding”, or “moderate inflammation” in a text report,
the addition of images allows better understanding of
what is actually found. This development parallels what
radiologists have been doing for a long time: relating
their diagnostic considerations directly to recorded
image material.

be entered, long after the endoscopy report is finalized
and dispatched.
Images as part of the report
The increasing availability of digital endoscopic images
is paving the way for their role in standard reporting of
endoscopic procedures. Accompanying a textual descrip-
tion of a finding with one or more pictures of the same
finding, together with a location diagram, significantly
enhances the value of the report, particularly for other
endoscopists who may interpret the images independ-
ently. Also, in the setting of repeat endoscopies for follow-
up of a finding, the ability to compare the appearance
of a lesion with previous images is invaluable for deter-
mining any progress or healing.
Color images require specialized printers, increasing
the cost of preparing the endoscopy report. A possible
option is to print images on a separate sheet of paper,
while the standard text report is printed on regular non-
color laser printers. With the further development of
cheaper color laser technology, this problem will prob-
ably diminish.
Free text vs. structured input
Traditionally, the endoscopy report was dictated into
the general medical record, similar to surgical proced-
ures or consultation notes. This model is still prevalent,
at least in Europe, and it is efficient and convenient for
the endoscopist.
Even in dedicated endoscopy reporting systems,
unstructured input is the rule rather than the exception.
Some systems require some degree of uniformity of the

chip in the tip of the endoscope has a pixel resolution in
the SVGA range. Thus, even if we had capture boards
with higher resolution, the image quality would only be
marginally better (Fig. 17.2). However, high-resolution
endoscopes are being developed that may change this
situation.
File compression
For practical purposes, uncompressed images are almost
a relic of the past. With the increasing utility of network-
based and Internet-based computer applications, the
need for smaller files is indisputable.
have come to expect in the medical history and physical
findings of a patient on admission. The introduction of
computerized reporting systems for endoscopy man-
dates a structured report. The use of these systems for
statistical analysis requires rigorous coding.
The digital revolution in endoscopy laboratories has
the potential to change the way endoscopists work and
communicate, offering great improvements in the ser-
vice to the patient and referring doctors. However, this
advance requires a nontrivial investment of money,
time, and thought on the part of the endoscopist. This
section deals with some of these issues.
Digital imaging
Imaging the gastrointestinal tract using a videoendoscope
requires several steps: illumination by fiberoptic light
transmission, surface reflectance, magnification, charge-
coupled device (CCD) conversion of the reflected light
to an electrical signal, reconstruction of the signals to
an image, and projection on to a monitor. Personal com-

hue variations, JPEG can compress hue (color) data more
heavily than brightness (gray-scale) data. A gray-scale
JPEG file is generally only about 10–25% smaller than a
full-color JPEG file of similar visual quality. However,
the uncompressed gray-scale data is only 8 bits/pixel or
one-third the size of the color data, so the calculated
compression ratio is much lower. The threshold of vis-
ible loss is often around 5 : 1 compression for gray-scale
images, substantially different from color images [1].
JPEG 2000 and beyond
The importance of image handling and compression for
Internet applications creates a huge momentum for
development. The JPEG working group has developed
a new standard, which is only just becoming avail-
able (accepted as an ISO standard December 2000). This
standard is called JPEG 2000, with the file extension .jp2.
This standard offers a host of advantages over the ex-
isting JPEG standard, the most significant being lack of
pixelation at high compression rates and significantly
more effective compression.
Although the file size of individual endoscopic images
is not a major issue at this point, we should keep in mind
that when the display and transfer of large numbers of
images and videos becomes a significant part of our
daily work-flow, even minute delays for every picture
will have an impact. Thus the continuing search for more
File compression is a computational processing tech-
nique that effectively reduces the size of a file, removing
redundancies in large binary datasets. Full-motion video
requires a frame display rate of 30/s. If each frame is 0.5

PNG (Portable Network Graphics). JPEG files have the
advantage of remaining 24-bit true-color files during
compression, while GIF files are limited to 8-bit color
(256 colors). The PNG file format shows promise as a
lossless compression method for the Web but has not yet
Fig. 17.2 Compressing a typical
endoscopic image from 140 kb
(already compressed from around
800 kb) to 12 kb is hardly noticeable.
204 Section 4: Reports and Imaging
ican Academy of Ophthalmology, and American Dental
Association have defined a new supplement to the
DICOM Standard [2]. This Supplement to the DICOM
Standard specifies a DICOM Image IOD for Visible
Light Images. This standard enables specialists working
with color images to exchange images between differ-
ent imaging systems using direct network connections,
telecommunications, and portable media such as CD-
ROM/DVD and magneto-optical disk. The DICOM
Standard for endoscopy is part of a larger standard for
color images in medicine that has been provisionally
approved by the DICOM committee. The current version
will go through a process of public comment and test-
ing. This ensures that any interested party can review
the document and suggest changes to a committee
responsible for creating the final version. This process is
time-consuming but ensures that the standard is com-
prehensive and meets the needs of a broad group of users.
Through the ASGE and ESGE, the endoscopy com-
munity has also suggested that the DICOM Standard

lesions were presented in an 8-bit, 16-bit, and 24-bit
format blindly side by side on a Macintosh II system
with a 19-inch monitor that could display 24-bit color.
efficient file compression will be of major significance for
medical imaging. PACS development currently suffers
from the high cost of high-end workstations and net-
works to handle huge image datasets.
DICOM
Digital imaging and communication in medicine
(DICOM) is a standard for imaging that contains very
specific information about the images, as well as the
images themselves. DICOM relies on explicit and detailed
models of how the “things” (patients, images, reports,
etc.) involved in imaging operations are described, how
they are related, and what should be done with them.
This model is used to create an Information Object
Definition (IOD) for all the imaging modalities covered
by DICOM.
An Information Object is a combination of Informa-
tion Entities and each Entity consists of specific Modules.
A Service Class defines the service that can take place
on an Information Object, e.g. print, store, retrieve. In
DICOM, a Service is combined with an Information
Object to form a Service/Object Pair (SOP). For example,
storing a computed tomography (CT) scan or printing an
ultrasound is an SOP pair. A device that conforms to the
DICOM Standard can perform this function. Thus, in a
DICOM-conforming network the devices must be cap-
able of executing one or more of the operations the
SOP definition prescribes. Each imaging modality has an

longer a reasonable yardstick for download time. The
virtue of compressing images remains but there is no
reason to compromise image quality in order to achieve
the tiny file sizes that yesterday’s technology recom-
mended. The endoscope manufacturers have been
struggling hard to offer high-resolution endoscopes,
structure enhancement, and magnification; it would be
counterproductive to lose these advantages for a few
kilobytes of file-size reduction.
As for clinical utility, we need to establish a general
standard for compression and formats that will work
across diagnoses. This will have to aim at a quality
sufficient for our most difficult diagnoses: subtle diffuse
lesions like mild gastritis or tiny erosions, or delineation
of the vascular pattern of a colitis.
Pictures or live video?
Increasingly, digital video is becoming an option for
endoscopic documentation. Many capture boards have
the capability of storing video as well as still images,
and in certain situations video may definitely offer an
advantage. This is particularly true for teaching purposes,
Eleven observers (six nurses and five endoscopists) were
asked to rank each format for each lesion. There were a
total of 330 observations and for each format and total
the results were similar: the observers identified cor-
rectly in 22% of the images; identified incorrectly in 37%
of the images; and could not see a difference in 41% of
the images. In addition, all the lesions were correctly
identified. From this study of endoscopic images, color
resolution does not appear to affect an endoscopist’s

Duodenal ulcers 183.6 5.6
Table 17.1 Clinical acceptability of
compressed gastrointestinal images.
(Adapted from Kim [1].)
206 Section 4: Reports and Imaging
sonable in this situation. For diffuse pathology, typically
more than one image might be preferable, and maybe
high resolution becomes an issue for minimal changes.
More complex still is the issue of nonpathology.
Which images are needed to exclude a lesion in order to
document a normal colonoscopy? We obviously cannot
picture every single fold, let alone behind them, but
there may still be reasons to document normality, e.g. to
show what kind of view, cleansing, and distension was
available to the endoscopist. The virtue of this becomes
even more obvious in the context of referrals and second
opinions. When we are asked to evaluate a polyp for
possible removal and pictures are sent from a referral
source, too often we discard that study because the
images that we receive are not the ones we expect. This
expectation needs to be incorporated into a standard that
will allow more efficient collaboration on patients based
on images alone. Too many repeat endoscopies are per-
formed because images are inadequate, although the
study may have been excellent.
The ESGE [4] has made an attempt to establish guide-
lines for standard endophotographs at specific sites in
the colon (Fig. 17.4) and has proposed a set of images at
various areas of the colon to aid in the visual identifica-
tion of each area (Fig. 17.5).

Quicktime and MPEG-1 formats, but this is a field of
continuous development, MPEG-4 being the most pro-
mising option at the moment. Most of the compression
algorithms use similar techniques, as discussed above
for still images. For example, if a segment of the movie
image is unchanged for a period of time (the sky, or the
black portion to the left of the endoscopic image), the
only information that needs to be stored is the bound-
aries of the area, the color value, and the start and stop
timecodes. With this type of compression, a video of a
newsreader for example can be reduced to a still picture
with a small moving segment representing the mouth.
This technique, in addition to a multitude of others,
allow for increasingly efficient compression of video
clips, offering efficient storage, as well as network-based
distribution, with none or minimal depreciation of the
diagnostic value.
What images are needed?
In parallel with the technologic developments in digital
imaging and video, there are important decisions that
need to be made by the endoscopic community. A crucial
one is: What pictures are needed? If we want to report a
polyp in the sigmoid colon, a single picture might be
sufficient if it is a good one, showing the size and shape,
stalk, amount of luminal obstruction, surface texture,
and so on. But what about a distal rectal lesion? An extra
picture of its relation to the anal verge might be import-
ant, not least if a surgeon was to remove it. A retroflexed
view as well as a standard forward view would be rea-
5

do not relate to digital imaging itself, but they all rely on
such imaging as the core technology for endoscopy.
Color manipulation methods deal primarily with the
color characteristics of the pixels representing the image.
This is a simple way of enhancing the contrast features of
the image, but sometimes at the cost of resolution. These
methods are so far only available for manipulation of
still images and a live version of the technology would
be needed to make this clinically applicable.
Narrow-band imaging and spectroscopy are just two ex-
amples of a host of other technologies that will enhance
the diagnostic yield. In these technologies, parallel “im-
aging” is used to extract information about the imaged
tissue, and the regular digital images are primarily used
to guide the process of advanced tissue characterization.
Fig. 17.5 Sample image set showing a colonoscopy of a
normal colon.
208 Section 4: Reports and Imaging
Minimal standard terminology
The OMED terminology, while defining the framework
for the terminology efforts within digestive endoscopy,
proved too complex for practical use in everyday
endoscopy. A simplification was needed and the ESGE
teamed up with its US counterpart the ASGE to develop
minimal standard terminology (MST) for endoscopy [5].
This terminology is completely based on the OMED ter-
minology but the lists of terms are limited, aiming to
cover 95% of the terms needed for typical endoscopic
practice and omitting the definitions, which are avail-
able when needed in the OMED terminology book. MST

core means of communication for the endoscopist and it
should be meaningful to endoscopists, general gastroen-
terologists, and referring practitioners alike. The report
should contain certain fixed elements in order to convey
fully the results of the examination, the diagnosis, and
recommendations. Modern communication methods
now permit the transfer of pictures of endoscopy along
with the written report. Elements of interest are detailed
in this chapter.
Acknowledgments
I would like to thank Dr Louis Korman and Dr Chris
Kim for valuable input to specific segments of this
manuscript and for their efforts in the field in general.
References
1 Kim CY. Compression of color medical images in gastroin-
testinal endoscopy: a review. Medinfo 1998; 9: 1046–50.
2 Korman LY, Bidgood WD Jr. Representation of the gastroin-
testinal endoscopy minimal standard terminology in the
SNOMED DICOM microglossary. In: Proceedings of the AMIA
Annual Fall Symposium, 1997: 434–8.
3 Vakil N, Bourgeois K. A prospective, controlled trial of
eight-bit, 16-bit, and 24-bit digital color images in electronic
endoscopy. Endoscopy 1995; 27: 589–92.
4 Rey JF, Lambert R. ESGE recommendations for quality
control in gastrointestinal endoscopy: guidelines for image
documentation in upper and lower GI endoscopy. Endoscopy
2001; 33: 901–3.
5 Delvaux M, Korman LY, Armengol-Miro JR et al. The
minimal standard terminology for digestive endoscopy:
introduction to structured reporting. Int J Med Inf 1998; 48:

to formulating our findings and recommendations in
natural language, and any superimposed structure will
take extra time, be felt as cumbersome and limiting,
and clearly as something that yields less informative
reports.
The solution to this has not yet been found, and MST
is at present primarily an excellent initiative. The utility
of standardized terms is indisputable; the challenge
is to embed this into software that allows them to be
sufficiently transparent. Also, it is unlikely and probably
unnecessary that the endoscopy report be produced
exclusively by “point-and-click.” Segments of the endo-
scopy report will probably remain free text blocks with
natural language.
210
4 cause no discomfort;
5 produce no significant shifts of fluids or electrolytes
[2].
The regimen should be simple and appropriate for use in
inpatients and outpatients [14]. The presently available
methods do not meet most of these criteria and few have
been carefully studied [1]. Problems with patient com-
pliance, safety, and adequacy of cleansing prompt con-
tinued investigation into alternative forms of cleansing
[15].
Colon cleansing methods
Traditional cleansing methods evolved from barium
enema preparations and local experience and were modi-
fied for colonoscopy and colon surgery. There are a wide
variety of methods using diet restrictions with various

colonoscopies, noting that suctioning fluid and washing
occupied a measurable percentage of total examining
time and that imperfect bowel preparation led to aborted
examinations and earlier repeat surveillance. These
problems resulted in an increase in average costs of 12%
at the university hospital and 22% at the public hospital
studied. Residual fecal matter also poses a risk from
ignition of combustible gases during electrocautery [1].
Hydrogen and methane are the two major combustible
gases found in the colon and explosions have been
reported during colonoscopy and other related proced-
ures [1,3,8–11]. Colon cleansing reduces the concentra-
tion of explosive gases [3,5,8,12,13].
Goals of preparation
A colon preparation regimen should provide safe and
rapid cleansing acceptable to patients with minimal dis-
comfort [1]. The ideal method would:
1 reliably empty the colon of fecal material;
2 have no effect on gross or microscopic appearance of
the colon;
3 require a short period for ingestion and evacuation;
Chapter 18
Preparation for Colonoscopy
Jack A. DiPalma
Table 18.1 Clear liquids.
Clear broth or bouillon
Coffee without creamer
Tea
Fruit juices without pulp
Gelatin

resulted in mean water absorption of 64 mL/h, whereas
infusion of a basic electrolyte solution without osmotic
balance resulted in water absorption of 799 mL/h [28].
Routine clinical cleansing using 3–4 L over 3–4 h would
result in absorption of 190–250 mL fluid with PEG-
ELS and 3400–3200 mL of electrolyte solution without
osmotic balance [14]. Furthermore, since saline lavage
frequently requires 7–12 L over 6–12 h, these patients
have the potential for over 8 L of water absorption. In
their report, Davis and colleagues [28] claimed that “any
solution worth its salt should have a name” and they
chose to call theirs Golytely, which subsequently became
the brand name of a commercial product (GoLYTELY,
Braintree Laboratories, Inc., Braintree, MA). PEG-ELS is
also available as CoLyte (Swartz Pharma, Milwaukee,
WI). Table 18.3 lists the commercially available gut
lavage products.
PEG-ELS
Clinical trials established the safety of PEG-ELS for colon
cleansing preparation for colonoscopy, barium enema
X-ray examination, intravenous pyelograms, and colon
surgery [4,12,29–34]. Compared with diet and cathartic
methods with enema administration, PEG-ELS had bet-
ter patient acceptance [4,12,29–31]. When compared
with clear liquid and minimum-residue diet methods,
PEG-ELS [12] was superior, with cleansing efficacy rated
juices, jelly, and gelatins, which could mimic blood dur-
ing colonoscopy. Beans, watermelon, and foods with
similar appearance could be confused with polyps.
The effect of diet was demonstrated in a prospective

senna X-prep was acceptable with good cleansing. Chen
and colleagues [19] showed magnesium citrate and
bisacodyl to be effective and superior to castor oil for
colonoscopy preparation.
A low-residue meal kit is available (Nutra Prep, EZ
Em, Inc., Westbury, NY). A companion laxative kit com-
pletes the preparation using magnesium citrate and
bisacodyl (LoSol, EZ Em, Inc.) [20]. Table 18.2 lists the
components of diet and cathartic regimens.
Gut lavage
Orthograde, peroral gut lavage using saline or balanced
Table 18.2 Diet and cathartic regimens. (Modified from Toledo and DiPalma [1].)
Diet Clear liquids for 72 h, or 1–3 days of a diet designed to result in a minimal colonic fecal residue
Cathartic Magnesium citrate 240 mL chilled, X-prep liquid 240 mg (extract of senna fruit, Purdue Frederick Co., Norwalk, CT)
Additional cathartic Bisacodyl 20 mg orally and/or two bisacodyl suppositories
Enemas Tap-water enemas until clear the evening before or morning of the procedure
212 Section 5: Preparation for Colonoscopy
leagues [37] showed that the mean percent urinary PEG
recovery of orally administered PEG-ELS was minimal
and similar for normal (0.06%) and inflammatory bowel
disease (0.09%) study subjects.
Clinical trials for colonoscopy, barium enema X-ray,
and elective colonic surgery showed SF-ELS to be safe
and effective [38–42]. In those who expressed a taste
preference, DiPalma and Marshall [39] showed SF-ELS
to be preferred to PEG-ELS (76.6% vs. 23.4%, respect-
ively; P < 0.001). In a conflicting report, Froehlich and
colleagues compared PEG-ELS and SF-ELS and found
no taste preference [40,42]. In a clever attempt to recon-
cile the conflicting data concerning taste preferences,

isolates water from the solution [27] and when PEG
molecular weight is greater than 1500 (as seen with PEG
3350 in PEG-ELS and SF-ELS), it is poorly absorbed in
the gastrointestinal tract. PEG is inert and not fermented
by colonic bacteria to combustible gases. Brady and col-
Table 18.3 Cost of colon cleansing. (Modified from Toledo and DiPalma [1].)
Price range* ($) Average price ($)
Diet and cathartic methods
Magnesium citrate 300 mL 1.16–4.99 1.31
Bisacodyl 5 mg
Generic (four tablets) 1.44–1.96 1.64
Dulcolax (four tablets) 2.89–4.99 3.95
Dulcolax suppositories (two) 3.99–6.49 4.96
Phosphosoda enemas (Fleet) (two) 0.89–1.44 1.10
Total diet and cathartic 8.93–17.91 11.32
LiquiPrep (EZ EM, Inc., Westbury, NY) 6.25
NutraPrep diet (EZ EM, Inc.) 25.00
LoSo Prep System (EZ EM, Inc.) 4.99
Polyethylene glycol electrolyte lavage solution (PEG-ELS)
GoLYTELY (Braintree Laboratories, Inc.) 23.72–32.69 27.07
Flavored GoLYTELY (pineapple) 24.79–27.09 25.94
CoLyte (Schwarz Pharma, Inc., Milwaukee, WI) 21.54–22.89 23.70
Flavored CoLyte (pineapple) 16.70–21.69 20.43
CoLyte with flavor packs (citrus, berry, lemon-lime, cherry, pineapple) 21.69–28.69 24.42
PEG-ELS (generic) 12.54–24.69 18.03
Sulfate-free electrolyte lavage solution (SF-ELS)
NuLYTELY (Braintree Laboratories, Inc.) 25.72–33.69 28.02
Flavored NuLYTELY (cherry, lemon-lime, orange) 25.72–33.69 28.02
Phosphates
Oral phosphosoda (Fleet’s Phospho-soda, C.B. Fleet, Lynchburg, VA) 6.78–7.18 6.98

Gut lavage in the elderly
To assess tolerance of colonoscopy preparation in older
patients, symptoms of nausea, cramps, abdominal full-
ness, vomiting, and overall discomfort were assessed
by self-administered questionnaires in over 550 study
subjects who received diet, cathartic and enema pre-
parations, or gut lavage [60]. In general, patients over
age 60 years tolerated preparations better than those
under 60 regardless of the type of preparation. Most
rated discomfort as “minimal”. The PEG-ELS method
was preferred by 81% of the older group. Age did not
influence adequacy of cleansing with either method.
Lashner and colleagues [61] randomized 124 con-
secutive patients over age 75 years to enema lavage or
PEG-ELS. Patients 75 or older seemed to tolerate enemas
better than PEG-ELS without a difference in cleansing
adequacy.
Pediatric use of gut lavage
Gut lavage has been used in children and infants
[18,62–65]. Compliance is limited by the volume required
for cleansing but lavage is preferred because of its
superior cleansing and limited adverse effects [18,63].
Dahshan and colleagues [18] advise that PEG-ELS be
taken 20 mL/kg per h up to 1 L/h for 4 h.
one brand with flavor packs of pineapple, citrus berry,
lemon-lime, or cherry. SF-ELS was flavored with cherry,
lemon-lime, or orange. Since flavorings are carbohydrate-
based, the SF-ELS solutions were studied and showed
no production of combustible gases in either flavored
or unflavored preparations [44]. A small study by Matter

for quality of preparation or residual colonic fluid aspir-
ated during colonoscopy [53,54]. Both bisacodyl and
magnesium citrate may reduce the volume of lavage
required for adequate cleansing [55,56].
Simethicone may decrease residual bubbles or foam
seen during colonoscopy [57], but cleansing enemas
seem not to improve preparation [58]. Tap-water enemas
after 4-L lavage did not improve visibility or decrease
colon fluid and may cause anorectal trauma [58]. There-
fore, enema administration is not necessary when using
a balanced electrolyte gut lavage.
Reduced-volume lavage
Sharma and colleagues [56] compared 4-L PEG-ELS
lavage with 2-L lavage with magnesium citrate pretreat-
ment. A second trial by this group evaluated PEG-ELS
214 Section 5: Preparation for Colonoscopy
placed, careful attention should be given to insure that
the tube is properly positioned. The patient should be
carefully observed. Gut lavage by nasogastric tube is
contraindicated in the presence of obstructive symptoms.
There are also reports of systemic allergic reaction to
PEG, although serious adverse effects have been rare
[70–72].
Administration options
Vilien and Rytkonen [73] used 1.5 or 3 L PEG-ELS in
combination with diet and cathartics. Rosch and Classen
[74] described a two-stage method, administering 3 L the
evening before colonoscopy and 1 L the following morn-
ing. Early studies administered 4 L PEG-ELS the day of
the procedure [12], while subsequent studies gave SF-

rated cleansing better from sodium phosphate than from
PEG-ELS. Hyperphosphatemia was noted but it was
transient and the preparation was considered safe.
Sodium phosphate monobasic, monohydrate and
sodium phosphate dibasic, anhydrous (Visicol, InKine
Safety of gut lavage
Several adverse experiences have been reported from gut
lavage. Table 18.4 lists reported and potential adverse
events [7]. Lavage patients may find taste disagree-
able. If the administrated solution is chilled excessively,
hypothermia may result. Bloating, nausea, and vomiting
can result from the volume of lavage and esophageal
tears have been reported. Pill malabsorption with slow-
release drug delivery preparations could occur, but most
tested capsules recovered in the colon show them to be a
“ghost” of the wax tablet matrix without active medica-
tion. Negligible hematologic and biochemical changes
have been seen in cleansing investigations but anecdotes
of pulmonary edema and anasarca exist. Metabolic and
acid–base abnormalities are unlikely and several stud-
ies have evaluated pH and bicarbonate changes from
PEG-ELS in a large number of patients [7]. Overall,
PEG-ELS and SF-ELS are preferred over phosphates and
cathartics for safety in renal, cardiac, and hepatic insuf-
ficiency where fluid balance is tenuous [1].
PEG appears nontoxic from animal and human stud-
ies [1]. Caution has been raised about PEG toxicity
[66–69] but studies show negligible absorption even in
patients with disrupted mucosa due to inflammatory
bowel disease [37]. The issue of carcinogenesis and

receiving sodium phosphate preparation [94].
Other options
There are various other ways to prepare for colonoscopy,
including intraoperative colonic irrigation [95] and
pulsed irrigation [2].
Special considerations
Colostomy
Colon cleansing in patients with colostomies can be per-
formed using any of the routine preparations [3].
Histology
PEG-ELS does not alter the appearance of colonic
mucosa [96]. Bisacodyl causes histologic and macro-
scopic changes in the colonic mucosa [97]. Phosphate
preparations may be associated with colonic aphthous
ulceration [94].
Lower gastrointestinal hemorrhage
PEG-ELS has been safely used in patients requiring
urgent colonoscopy [98–100]. Some require as little as
500 mL for cleansing. In a study of 35 patients, effective
cleansing was seen with good tolerance and no com-
plications [99].
Inflammatory bowel disease
In general, patients with quiescent inflammatory bowel
disease can be prepared in the usual manner with any
preparation [3]. Those with moderate or severe dis-
ease could be prepared with less purgatives or no pre-
paration. The PEG-ELS study showed no significant
PEG absorption in patients with inflammatory bowel
disease even when mucosal inflammation is present
[37].

phosphate were studied in seven healthy asymptomatic
adult volunteers [90]. Calcium, ionized calcium, phos-
phorus, sodium, potassium, creatinine, and parathyroid
hormone were analyzed 2, 4, 6, 9, 12, 14, 16, 18, 21 and
24 h after the first of two diluted 45-mL oral sodium
phosphate challenges. Urinary studies and clinical
data were also obtained. Significant hypocalcemia and
hyperphosphatemia were observed. The peak range in
phosphorus was 3.6–12.4 mg/dL. The nadir calcium
fall was 8.0–9.8 mg/dL, with a corresponding fall in
ionized calcium. Concern was raised for patients with
cardiopulmonary, hepatic, or renal disease. An FDA
safety review concurs and raises awareness of increased
risk in patients with congestive heart failure, ascites,
renal insufficiency, dehydration, debility, gastrointest-
inal obstruction, gastric retention, bowel perforation,
colitis, megacolon, ileus, inability to take oral fluid, or
patients taking diuretics or medications that may affect
electrolytes, who may experience serious adverse events
[91]. The review suggests that baseline and posttreat-
ment laboratory evaluations of serum sodium, potas-
sium, chloride, bicarbonate, calcium, phosphate, blood
urea nitrogen, and creatinine be obtained, especially in
those at risk who take more than 45 mL oral sodium
phosphate in a 24-h period. Chan and colleagues [92]
noted in a utilization survey of Canadian gastroenter-
ologists that colonoscopists appeared unaware of the
potential for complications from phosphates, even in
these special circumstances.
Another FDA report raises concern about phosphate