Optiscan claims good results from Pentax partnership

The 25,000 doctors attending the world's largest gastroenterology meeting in Chicago next month will be briefed about a revolution in the detection and diagnosis of gastrointestinal diseases, engineered by Melbourne's Optiscan (ASX:OIL) and its giant Japanese partner Pentax.

Clinicians from Germany, the US, Japan, Singapore and Australia have been test-driving the Optiscan/Pentax confocal endomicroscope, with what are said to be spectacular results.

The new endomicroscope will allow clinicians to diagnose diseases of the gastrointestinal tract in situ, rapidly, and precisely, without the need for painful, potentially error-prone biopsy procedures.

Gastroenterologists trained in the use of the new device will become their own pathologists, able to inspect living tissues at very high magnification to detect ulcerous lesions, cancerous cells, or even spot the spiral cells of the ulcerating bacterium Helicobacter pylori.

Researchers will present a series of papers at the Digestive Diseases Week conference on the expanded range of diseases that can now be detected and diagnosed with the new endomicroscope. They include Barrett's oesophagus, oesophageal cancer, ulcerative colitis, colorectal cancer, gastric cancer, and Helicobacter infections.

The new device comprises a conventional, flexible endoscope with an articulated head that can be turned at right angles, containing high-intensity 'headlight' to illuminate the gastrointestinal tract. There is also a channel for introducing miniaturised surgical instruments.

But the heart of the device is a laser confocal microscope, comprising a miniature scanner linked by optical fibre to a charge-coupled device (CCD) digital video camera. The penetrating power of the laser induces natural fluorescence in the tissues, and computer processing of the scanner data yields very high magnification images, in three-dimensional detail.

The head of the endoscope feeds simultaneous images to adjacent screens in front of the operator. One shows the tissues at normal magnification, so the endoscopist can navigate and orient the scanner towards areas of interest, and then image them at very high magnification on the second screen.

Optiscan's director of technology, Peter Delaney, said that its reliability had "surpassed even our own expectations".

"The key question in gastroenterology is whether we can see the pathology, and do it interactively, in real time," he said. "When we started developing the endomicroscope many years ago, the question was whether endoscopists would need to be pathologists.

"It's not like the conventional pathology view, where a biopsy is obtained, cut at an artificial angle, then sectioned and stained. The endomicroscope presents living cells in their real-world orientation.

"Because you're looking at living tissue, you see things you don't see in a conventional biopsy, like the intact microvasculature, inflammatory processes, and blood cells -- there's a whole new world of information that is simply available from conventional biopsies.

"And even though it's real time, and interactive, the opinions the gastroenterologist forms agree very closely with those obtained from conventional pathology."

Cancer diagnosis

Delaney said one of the most exciting applications of the new endomicroscope was in diagnosing Barrett's oesophagus and its potential sequel, oesophageal cancer.

Up to one in five people in Western society suffer from chronic heartburn, which leads to the cellular abnormalities, Barrett's oesophagus, a precursor to an aggressive form of oesophageal cancer. There are five million patients with Barrett's esophagus in the US alone.

Patients undergo regular endoscopic surveillance to detect the earliest signs of cancer of the oesophagus, while the disease is still treatable.

But the procedure requires very large numbers of biopsies -- as many as 35 per visit -- and even at this density, pre-cancerous tissues can be overlooked because the random sampling results in bleeding that obscures the endoscope.

The procedure is time-consuming and expensive, but studies have shown that doubling the spacing of the biopsies can result in 50 per cent of cancers being missed.

Optiscan said that German investigators at Mainz University Hospital had achieved very high diagnostic accuracy -- 97.5 per cent -- using the Optiscan/Pentax endomicroscope to observe the tissues directly, without taking biopsies.

The Mainz researchers have achieved 97.8 per cent accuracy diagnosing ulcerative colitis, and 100 per cent accuracy with Helicobacter infection.

Researchers at Singapore's National University Hospital have achieved 80 per cent accuracy in diagnosing gastric cancer with the new instrument, while a team at Melbourne's Cabrini Hospital has achieved 99.2 per cent accuracy for colorectal cancer and ulcerative colitis.