| Computerised
Imaging Colposcopy
- A Clinician’s Perspective
Colposcopy has traditionally relied on the binocular
stereoscopic examination of the cervical epithelium
and its underlying vascular stoma. It has been proven
to be highly effective tool in its own right as well
as in conjunction with histopathology.
However the effectiveness of colposcopy is dependent
on the expertise of the colposcopist and studies have
shown that the examination is subject to both inter
and intra-observer variability. Consequently, many
studies using colposcopy/histology as reference standards
have employed the technique of colposcopy review by
a second or even a third colposcopist to arrive at
a consensus diagnosis.
The use of computerised digital image capture and
its ability to store and transfer high resolution
images without degradation in quality has revolutionised
the process of colposcopy review. Images captured
on such a system can be accessed via a modem on the
Internet at a remote site and reviewed by an expert
colposcopist. There are also implications for the
primary healthcare setting where, like in cervicography,
images of the cervix, after application of acetic
acid can be obtained and sent for expert analysis.
Another advantage of computerisation is the ability
to document colposcopic findings directly on to an
existing image. The traditional method of drawing
colposcopic findings on paper has several disadvantages,
including the inability to accurately document lesion
size and subtle colposcopic changes. There are now
computerised systems that will not only allow annotations
to be made on the image but may also calculate the
surface area of any lesion. In addition, electronic
filters may be utilised to highlight particular areas
and de-emphasise others if needed.
These images can be accessed to follow the progression
or regression of lesions over time, and a photographic
quality printout obtained if required. This is particularly
useful in the patient who is being followed up colposcopically
e.g. in pregnancy.
This facility of documenting findings directly on
to a digital image allows the colposcopist to continually
assess and audit his or her own diagnostic accuracy
compared with histology. In addition, it has proven
to be an invaluable tool in the teaching and training
of colposcopists.
I have been using such a system (MediScan, Polartechnics
Limited, Sydney) in my practice for several years,
and will be showing a series of digital colophotographs
and demonstrating the use of an annotation system.
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