Learn how endoscopic imaging has changed over the last few years. You will also see photographs of chromoendoscopy (using clever colour enhancements to improve the endoscopic images) to assess oesophageal cancer risk.
A fibre optic image from 25 years ago
Originally, endoscopy used fibre-optics to obtain images. Then video cameras came along and our views of the inside of the body improved dramatically. Over the last few years, the quality of endoscopes has improved exponentially. Just look at these photos and see how much more detail we can now see when we use the best equipment.
Most endoscopy tests are now done with video systems. Everyone knows that a good camera has 10 mega-pixels or more. The more pixels, the better the picture.
The number of pixels in the endoscope picture is tiny compared to a normal camera. Most endoscopes still use about 400,000 pixels (0.4 mega-pixels). But remember: the area being examined is tiny so the resolution is actually higher than a standard camera. |
The latest scopes now have anywhere up to 4 mega-pixels. This dramatically improves the quality of the images and has made an enormous difference. When an Ultra-HD screen is used to show the images, the endoscopist can see minute abnormalities in clear detail.
Experts can now easily spot most abnormalities which could not be seen even a few years ago. Many units do not yet have access to this technology. Each endoscope cis very expensive so new equipment is not bought often. Even when high resolution scopes are available, it is really important for these endoscopy tests to be done by specialists in Barrett’s oesophagus. Doctors who are not trained in looking for the very subtle early (pre-)cancerous abnormalities will simply not recognize them even though they are visible to experienced, well trained operators. |
Chromoendoscopy means using colour to look inside.
A number of ‘vital dyes’ have been tried by doctors over the years. These include:
Methylene blue
Methylene blue is a blue dye which gets taken up into the cells in the lining of the oesophagus. It makes it easier to see subtle abnormalities. Many studies have been done to see if it improves diagnosis. Sadly, most of them show that it is of ne extra benefit. It is certainly messy and if it gets into the nurse’s or doctor’s clothes, they get ruined. Methylene blue has lost favour because of these weaknesses.
Indigo carmine
Indigo carmine is a purple dye. Unlike methylene blue, this dye does not get into the cells. Instead, it sits in the tiny crevices and dents between the cells. The purple colour highlights changes in the regular patterns of the cells. This draws the doctor’s eye to areas of abnormality that would not otherwise be seen.
A few studies have been done on the value of indigo carmine in Barrett’s oesophagus. Just like methylene blue, it seems that this dye does not help very much with diagnosis.
Acetic acid
Acetic acid is also known to most of us as vinegar. This simple substance is perhaps the best of all the ‘dyes’ for detecting abnormalities. Using a simple spraying tool, a small amount of vinegar is sprayed onto the lining of the oesophagus during the endoscopy. It is painless. Within 30 seconds, the colour of the lining changes from salmon red to white. Abnormalities are highlighted. Areas which do not go white often contain (pre-)cancerous abnormalities. These areas are also more likely to bleed a little.
Biopsy samples are taken and sent to the laboratory to confirm the findings. Unlike the older chromoendoscopy dyes, acetic acid does not make a mess. It also disappears within a couple of minutes.
Virtual Chromoendoscopy
Many endoscopes have extra imaging modalities built in. These make it easier for the doctor to see abnormalities without needing to use messy dyes.
There are three major image manipulation systems in use:
These systems work in different ways, but all aim to do the same thing. That is to detect (pre-) cancerous abnormalities more easily. They manipulate the colour of the images. This really can improve detection significantly when used by an expert who is trained and has experience with using them.
Large numbers of patients have been studied using enhanced imaging modalities. These studies have shown that more abnormalities are detected – but not for the reasons you might suspect…
It turns out that better detection is actually due to the longer time doctors spend carefully examining the inner lining of the oesophagus. The way doctors do this, whether with high-resolution, white light or with enhanced imaging appears to be of only minor importance.
The key is therefore to find an experienced gastroenterologist who knows what to look for. Our doctors are amongst the best in the world. We run national and international training courses for other doctors and are at the forefront of research into this new area of medicine.
Using advanced imaging techniques is useful, but it does not remove the need for the basic principles which remain: