Virtual Colonoscopy

For many people with insoluble digestive problems, a physical examination of the colon by means of a colonoscopy is advised. Colonoscopy is also the diagnostic tool of choice (after an initial stool test) to diagnose bowel cancer - and for many people with unsolved bowel problems, the under-lying fear of undiagnosed cancer is always present.

However, colonoscopy - the pushing of a long flexible tube with a tiny camera at its end, up through the colon via the rectum - is an unpleasant, embarrassing and often painful procedure, especially for those suffering from digestive disorders. So the take-up on colonoscopies is very low.

But now a new, state-of-the-art, ‘virtual’ colonoscopy can give, via some clever computer technology, a more detailed view of the colon than a standard colonoscopy, with a minimal amount of discomfort and embarrassment.

Professor Nick Read, chair of the IBS Network, took his colon along to be inspected - and describes the procedure.

Colonic symptoms usually mean painful and embarrassing investigations. Not any more! Imagine being able to have the whole of your colon inspected in great detail without the pain of having six feet of thick plastic tubing manoeuvred around inside you, or having a pint or so of viscous barium pumped into the colon. Impossible? Not so.

Recently, I was invited to experience a virtual colonoscopy in the service of the members of the IBS Network. A very noble gesture, I thought. But after spending Bank Holiday Monday drinking large quantities of Miso Soup (without the bits) and flushing my system out with Picolax, my bottom was sore and I was feeling distinctly less ennobled.

Clean both outside and in, I caught the early train to London for my appointment at the European Scanning Centre at 68 Harley Street. Despite my rumbling tummy, I allowed myself to be escorted by a pleasant young lady down to the basement where I put on a pale blue robe, which did up at the back, and a Japanese dressing gown and slippers. I was allowed to keep the slippers! Then a staff member with a well-practised line of humour told me to lie on the narrow platform that went inside the scanner and with great skill, inserted a catheter in a vein in my arm and slid a very small lubricated tube into my bottom. An intravenous injection of Buscopan dried my mouth and caused a not unpleasant fluttering in my chest, while at the other end, the insufflation of air into my rectum produced a rather pleasurable bubbling sensation in the pelvis and abdomen.

Floating through the Scanner
Then, as the contrast medium was infused to outline the blood vessels and kidneys, I was overwhelmed by a sensation of warmth, first in the throat, then over the eyes and all over the body. Adrift on a strange sensual journey, I did not really care what happened next. So, folding my arms above my head and holding my breath, I was slowly propelled through the ring of the scanner, amid lots of buzzing and whirring. This was repeated four times, twice on my front and twice on my back. Then the intravenous catheter and rectal tube were removed and it was all over: just half an hour from start to finish.

Although I was conscious of a rather distended abdomen, I was still able to enjoy two cups of nice peppermint tea and a smoked salmon and salad sandwich. There was just one moment of anxiety when I discovered that it was a little difficult to pass urine and to expel the air they had pumped inside the colon but within ten minutes that had passed and while chatting amiably to the director, Dr Jenkins, I was able to evacuate the gas without any sound or smell.

How Does it Work?
Dr Jenkins’ day job was as a consultant endocrinologist at St Bartholomew’s Hospital. He explained that the virtual colonoscopy employed an electron beam from a rotating tungsten crystal to bounce off the inside surface of the colon and generate hundreds of thin images throughout the entire length of the colon. By some clever computer technology that was quite beyond me, these images are reconstructed to yield a highly detailed continuous image of the colon all the way from the anus to the caecum.

Now I do realize that many would be happy for this part of their bodies to remain ‘a dark continent’, a land of mystery, but not me. I was intrigued to discover that my colon was abnormally long – about six feet to be exact and folded in on itself in the most tortuous manner – must be all the muesli I’ve eaten over the years - or is it just a metaphor for my life! The play back of the voyage through my colon took quite a long time as the computer negotiated the folds and corners of the sigmoid colon punctuated by little pockets or diverticuli, the semilunar folds of the descending colon, the beautiful triangular gothic arches of the transverse colon and the large cavern of the ascending colon and caecum with the entrance to the appendix as a hole in the distance. Wonderful! And luckily there were no polyps nor any evidence of cancer.

The electron beam scanner can detect polyps as small as six millimetres in diameter. This is almost as sensitive as direct vision through an endoscope, but unlike direct colonscopy, it does not miss polyps tucked around corners or in parts of the colon that are impossible to get to. A colon as tortuous as mine would be difficult to navigate with a colonoscope.

Facts and figures on Colorectal Cancer
Colorectal cancer is the second most common cause of cancer-related death in women and the third in men. Within five years of its diagnosis, 61% of people die. About 30,000 colonic cancers are diagnosed in the UK every year, but many have gone too far for them to be removed. ninety percent of malignant cancers of the colon develop from polyps, and about 35% of older people have polyps in their colons.
It takes about 10 to 15 years for a benign colonic adenoma to develop into an invasive cancer, so early detection is important. Cancer of the colon, if caught early enough, is a treatable condition. Adenomatous polyps can be snared and cut out without opening the abdomen before they have a chance to spread. Dr Jenkins believes everybody over the age of 50 should have a scan every five years.

Facts and figures on Virtual Colonoscopies
The electron beam scanner is much more sensitive than the conventional scanner. Consequently, a full examination of the colon takes a fifth of the time and uses significantly less radiation. Virtual colonoscopy is a painless procedure than can be carried out at lunchtime with little interruption of the day’s activity. I was able to go shopping in the afternoon and take in a Prom concert in the evening with no discomfort.

You should consider having an EBCT colon scan if you are over 40 and have a family history of colon cancer and/or you have experienced rectal bleeding and have suffered a recent unusual change in bowel habit. It is important to mention, however, that people with chronic Irritable Bowel Syndrome are not at more risk of developing colonic cancer than other people, but if your pattern of symptoms changes or you experience blood loss, you should see your doctor and consider further investigations.

If you have been referred by your doctor, your results will be sent directly to him or her by means of a written report and CD containing scan images within 72 hours of the appointment. If, however, the views of your scan show signs of disease requiring treatment, the European Scanning Centre will inform your doctor straight away and can also provide details of suitable specialists able to provide the treatment you require. The virtual colonoscopy is not cheap. It costs a thousand pounds, but what price do you put on reassurance and confidence?

If you wish to find out more about virtual colonoscopies, the European Scanning Centre is at
68 Harley Street, London W1G 7HE tel 020 7436 5755 www.europeanscanning.com

(This article first appeared in the Winter 2004 issue of Gut Reaction, the journal of the IBS Network, Unit 5, 53 Mowbray Street, Sheffield S3 8EN tel 0114272 3253 www.ibsnetwork.org.uk)


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First Published in 2005

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