Endoscopic diagnosis of reflux-oesophagitis with special regard to computerized image processing

The advent of the video endoscope is an important step in endoscope technology and it is of vital importance in the linkage between endoscopy and computers. The Charge Coupled Device ( CCD ) of an electric video endoscope transforms the light reflected from the mucosa into electric signals. These signals are in turn converted in the video processor unit into a digital image which is presented on the monitor. The digital image is suitable for different kinds of image processing with the main purpose to enhance the information stored in the image.

Pathological mucosa has very often subjectively a colour (objectively; difference in absorption spectrum) which is different from that of normal mucosa. Such differences can be analysed quantitatively by means of a colorimetric image processing. The generally most accepted methods for diagnosing reflux oesophagitis are endoscopy with biopsy, pH-measurement and manometry. No universally accepted classification system for the endoscopic staging of reflux oesophagitis exists, but the Savary-Miller classification is the most commonly used. Computerized quantification of the extent of the mucosal lesions by means of colour analysis of the endoscopic images could allow us to establish a more objective classification system of reflux oesophagitis. The important role of the microcirculation in the mucosa in the gastrointestinal tract has been emphasized in the development and healing of peptic ulcerations and other gastrointestinal diseases. An estimation of the mucosal hemoglobin content appears to be important in elucidating the role of the mucosal blood flow in the pathophysiology of gastrointestinal diseases. The greater part of the pigments in the mucosa in the gastrointestinal tract are hemoglobin. Light from the endoscope is composed of the three primary colours (red, green and blue). The hemoglobin will absorb the green light but reflect most of the red light. Therefore it is possible to estimate the hemoglobin content in the mucosa using the difference of the intensity of the red and green light. Endoscopic real-time analysis of the mucosal hemoglobin content in the oesophageal mucosa can by done by combining reflectance spectrophotometry with electronic endoscopy and an image processing system.