Three-dimensional (3D) imaging is gaining popularity and has been partly adopted in laparoscopic surgery or robotic surgery but has not been applied to gastrointestinal endoscopy. As a first step, we conducted an experiment to evaluate whether images obtained by conventional gastrointestinal endoscopy could be used to acquire quantitative 3D information.

Two endoscopes (GIF-H260) were used in a Borrmann type I tumor model made of clay. The endoscopes were calibrated by correcting the barrel distortion and perspective distortion. Obtained images were converted to gray-level image, and the characteristics of the images were obtained by edge detection. Finally, data on 3D parameters were measured by using epipolar geometry, two view geometry, and pinhole camera model.

The focal length (f) of endoscope at 30 mm was 258.49 pixels. Two endoscopes were fixed at predetermined distance, 12 mm (d₁₂). After matching and calculating disparity (v2-v1), which was 106 pixels, the calculated length between the camera and object (L) was 29.26 mm. The height of the object projected onto the image (h) was then applied to the pinhole camera model, and the result of H (height and width) was 38.21 mm and 41.72 mm, respectively. Measurements were conducted from 2 different locations. The measurement errors ranged from 2.98% to 7.00% with the current Borrmann type I tumor model.

It was feasible to obtain parameters necessary for 3D analysis and to apply the data to epipolar geometry with conventional gastrointestinal endoscope to calculate the size of an object.

Since endoscopes are reusable apparatus classified as semicritical item, thorough reprocessing to achieve high-level disinfection is of utmost importance to prevent spread of infection. To improve disinfection efficacy and safety, disinfectants and endoscope reprocessors are continuously evolving. This study aimed to compare the efficacy of the combination of polyhexamethylenebiguanide hydrochloride-alkyldimethylbenzylammonium chloride (PHMB-DBAC) and orthophthalaldehyde (OPA) used respectively in ultrasonographic cleaning incorporated automated endoscope reprocessors: COOLENDO (APEX Korea) or OER-A (Olympus Optical).

A total of 86 flexible upper endoscopes were randomly reprocessed with either COOLENDO/PHMB-DBAC or OER-A/OPA. Culture samplings were done at two sites (endoscope tip and working channel) which were later incubated on blood agar plate. Bacterial colonies were counted and identified.

The culture-positive rate at the endoscope tip and working channel was 0% and 2.33% for COOLENDO/PHMB-DBAC and 4.65% and 0% for OER-A/OPA. Staphylococcus hominis was cultured from one endoscope reprocessed with COOLENDO/PHMB-DBAC and Pseudomonas putida was isolated from two endoscopes reprocessed with OER-A/OPA.

The reprocessing efficacy of COOLENDO/PHMB-DBAC was non-inferior to that of OER-A/OPA (p=0.032; confidence interval, -0.042 to 0.042). During the study period, significant side effect of PHMB-DBAC was not observed.