Medicsight PLC (AIM: MDST), industry leader in the development of Computer-Aided Detection (CAD) and image analysis software which assists in the early detection and diagnosis of disease, draws attention to the recent announcement of preliminary results of the National US Computerised Tomography (CT) Colonography Trial (ACRIN study 6664). The results are expected to lead to wider adoption of CT colonography (also known as virtual colonoscopy) as routine screening for colorectal cancer.

David Sumner, Chief Executive of Medicsight, said: "We welcome the results of this landmark study, confirming our belief that CT colonography is a genuine and robust option in the armamentarium that physicians have at their disposal when screening for colorectal cancer. This is likely to lead to a material increase in the use of CT colonography for screening populations aged 50 or more who are most at risk of developing this devastating condition. Medicsight's ColonCAD™ software, which can be used with multi-detector CT imaging equipment, helps radiologists to interpret the CT scans and identify early-stage lesions. We expect the Company and its CAD software to be an important beneficiary of this trend."

The US trial has compared the detection of polyps and early-stage cancer of the colon using either conventional optical colonoscopy or CT colonography, in which X-ray slice images are reconstructed by computer to provide a virtual image of the colon. This study, funded by the US National Institutes of Health, was initiated in 2005 and has involved more than 2,500 asymptomatic patients aged 50 or over at 15 centres across the USA. Patients were investigated using both procedures and the resulting CT images were read by a panel of radiologists. The headline results of the study, released at the ACRIN 2007 Fall Meeting in Arlington, Virginia on 28 September, demonstrate convincingly that CT colonography is at least as sensitive and specific as conventional colonoscopy in detecting adenomas of 1 cm diameter or larger.

Colorectal cancer is the second leading cause of cancer death in the US. When colorectal cancer is detected early the survival rate is high. Those most at risk, aged 50 or older, are recommended to be screened regularly. However less than half actually undergo colonoscopy. Conventional optical colonoscopy, involving the insertion of a flexible metal tube into the colon, remains the "gold standard" for detection of early-stage tumours, not least because tissue samples can be taken at the same time as they are visualised. However CT colonography is non-invasive, less uncomfortable for the patient and offers the potential of routine screening. The results of the ACRIN 6664 study are expected to lead to reimbursement for CT colonography by Medicare and health insurance companies and thereby drive wider adoption of this technique and increased levels of screening in the at-risk population.

Dr Stuart Taylor of University College Hospital, a principal investigator for Medicsight, commented: "This very well designed study is the largest to date which has specifically investigated the use of CT colonography to screen for colorectal neoplasia in asymptomatic individuals, and has produced very positive results. The 90% sensitivity for identifying patients harbouring a 1 cm adenoma essentially validates the previously reported excellent performance of screening CT colonography by Dr Perry Pickhardt in 2003. I think we can now conclude that, when performed by appropriately trained readers, CT colonography is a viable and robust screening tool for colorectal cancer."

For further information:
Medicsight PLC
David Sumner
Tel: +44 (0)20 7605 7950
www.medicsight.com

Collins Stewart Europe Limited
Tim Mickley
Tel: +44 (0)20 7523 8350
Jonny Sloan
Tel: +44 (0)20 7523 8302

Media enquiries:
Abchurch
Ashley Tapp
Tel: +44 (0) 20 7398 7700
ashley.tapp@abchurch-group.com

Stephanie Cuthbert
Tel: +44 (0) 20 7398 7700
stephanie.cuthbert@abchurch-group.com
www.abchurch-group.com

Notes to editors

Medicsight PLC is a UK-based, research driven, leading developer of computer-aided detection (CAD) and image analysis software for the medical imaging market. The CAD software automatically highlights suspicious areas on computerised tomography (CT) scans of the colon and lung, helping radiologists to identify, measure and analyse potential disease and early indicators of disease. Medicsight's computer-aided detection (CAD) software has been validated using one of the world's largest and most population diverse databases of verified patient CT scan data. Medicsight's ColonCAD™ and LungCAD™ software products are seamlessly integrated with the advanced 3D visualisation workstations of several industry-leading imaging equipment partners.

About Computer-Aided Detection

With increasingly sophisticated radiological imaging hardware such as Multi-Detector CT scanners, radiologists are facing a growing challenge in the amount of detailed patient image data that they must review for each patient examination. Some CT scan examinations generate as many as 1000 images per patient. Review of this data by the radiologist is not only time-consuming but also prone to error due to reader fatigue. CAD software can help the reviewing radiologist by analysing the image data and automatically highlighting suspicious regions of interest for closer inspection. Without CAD software some potential abnormalities or areas of disease may be overlooked. This is critical for diagnosis and the management of patient outcomes as early detection of disease greatly increases the probability of successful treatment and a positive therapeutic outcome.

About Medicsight's CAD software

Medicsight's ColonCAD™ and LungCAD™ software use an advanced CAD algorithm to analyse CT scans of the colon and lung and automatically highlight suspicious areas that may be indicators of disease. CAD may highlight areas easily overlooked by the reviewing radiologist, such as small lesions or regions that are hidden from view behind folds in the colon or normal structures and surrounding tissue in the lung.

Both CAD products seamlessly integrate with the advanced 3D visualisation platforms of industry-leading imaging equipment partners. The integrated systems provide sophisticated image viewing capabilities, including 3D reconstructed image data, with the added advantage of demonstrating automatic CAD findings to assist clinical end users in the detection and analysis of disease. This allows clinical end users to perform either a 'second read', where CAD findings are displayed to the user after completion of an initial review of the CT scan data, or a 'concurrent read' where CAD findings are displayed during the user's initial review of the original CT scan images.

Since inception, Medicsight has developed close and lasting relationships with some of the world's foremost clinicians in product related areas. This provides the Company with a wealth of clinical expertise and dedicated clinical research to support ongoing product development. Medicsight also collaborates with a number of leading academic institutions and clinical research programmes worldwide to develop the Company's comprehensive database of population diverse verified patient CT scan data, thus allowing Medicsight's products to be validated to the highest possible standards.

About ACRIN

The American College of Radiology Imaging Network (ACRIN) is a national cancer research organization sponsored and funded by the US National Cancer Institute.

About adenomas

An adenoma (sometimes known as a polyp) is a slow-growing benign tumour. This is the most common type of early-stage tumour found in the colon and typically projects into the colon from the wall. Adenomas are routinely removed on identification because of their tendency to become malignant.