Medicsight PLC

("Medicsight" or "the Company")

Additional Information request for FDA 510(k) Clearance of

ColonCAD software

Medicsight PLC (AIM: MDST), industry leader in the development of Computer-Aided Detection (CAD) and image analysis software which assists radiologists in the early detection of disease, announces that on 5 January 2010 it received a further request for Additional Information (AI) letter from the US Food and Drug Administration (FDA) relating to the Company's currently pending 510(k) pre-market notification for the ColonCAD API 3.1 product.

The FDA previously issued an AI letter to the Company in December, 2008 requesting clarification of the intended use of the product, to which the Company responded. In the most recent AI letter the FDA has requested further technical details regarding the clinical trials and data analyses undertaken to support clearance of the product.

FDA 510(k) submissions for Class 2 devices such as the current ColonCAD API 3.1 submission are necessarily complex and require the sponsor company to provide a great deal of information relating to the design, manufacture and validation of the product. It is not unusual for a second AI request to be received by a company in order for the FDA to gain all the information they require in order to assess a device. However, the FDA's 510(k) process is typically restricted to two AI letters.

Allan Rowley, CEO of Medicsight, said: "We are working expediently with our clinical and statistical advisors and the FDA to prepare the requested information and expect to respond fully to the FDA before the deadline of 21 June 2010."

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Notes to editors

Medicsight PLC is a UK-headquartered, 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 CAD software has been developed 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 2000 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 can be 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. In addition to supporting individual radiologists CAD also has the potential to help standardise CT interpretation across both individuals and institutions thereby supporting population based screening programmes.

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.