Optical performance of electronic imaging systems for the colon.

Electronic (video) endoscopes are a significant new development in gastroenterology, offering the potential of enhanced teaching and permanent storage of pictorial data. The primary concern of gastroenterologists is the resolution and color performance of these instruments, as these parameters have important bearings on the ability to discern pathological changes in mucosa. We sought to determine the resolution and color capabilities of electronic colonscopes and compare them with a conventional fiber colonoscope. Resolution was determined using a standard test chart at various distances and the number of picture elements (a measure of resolution) was calculated. The mean number of picture elements was Fujinon (219), Fiber (172), Pentax (169), Toshiba (142), Olympus (140), and Welch Allyn (133). In close focus examination (target distances <1 cm), the Fujinon and Toshiba endoscopes had significantly higher resolution than the other instruments. Color was measured quantitatively using a standard color chart and a color analyzer. Color polygons were plotted for each endoscope on a reference chromaticity diagram. All systems had an acceptable overall performance but color was undersaturated with some systems. The optical performance of electronic endoscopes has improved considerably since the inception of electronic endoscopy

Cardiovascular events associated with rofecoxib : final analysis of the APPROVe trial

Background: Selective inhibition of cyclo-oxygenase-2 has been associated with an increased risk of cardiovascular events in several clinical trials. The Adenomatous Polyp Prevention on Vioxx (APPROVe) study assessed the effect of 3-year treatment with a cyclo-oxygenase-2 inhibitor, rofecoxib (25 mg), on recurrence of neoplastic polyps of the large bowel. We report the cardiovascular outcomes of a long-term follow-up of participants in the trial. Methods: The APPROVe study is a multicentre, randomised, placebo-controlled, double-blind trial. 2587 patients with a history of colorectal adenomas were recruited at 108 centres worldwide during 2000 and 2001. Participants were followed for adverse events while on treatment and during the following 14 days. However, after early termination of treatment because of cardiovascular toxicity, we attempted to follow up all randomised patients for at least 1 year after stopping study treatment. External committees blindly assessed potential serious cardiovascular events. The focus of the analysis was the combined incidence of non-fatal myocardial infarction, non-fatal stroke, and death from cardiovascular, haemorrhagic, and unknown causes (Antiplatelet Trialists' Collaboration [APTC] combined endpoint). We used Cox proportional hazards regression to calculate endpoint hazard ratios. The study is registered with ClinicalTrials.gov, number NCT0282386. Findings: We obtained extended post-treatment cardiovascular follow-up data from 84% of participants, and extended mortality follow-up from 95%. In total, 59 individuals had an APTC endpoint in the rofecoxib group and 34 in the placebo group (hazard ratio 1.79, 95% CI 1.17-2.73; p=0.006). In the first year after cessation of treatment, there was a non-significant increase in the risks of APTC endpoints. The APTC hazard ratio did not substantially change over time. Interpretation: Use of rofecoxib is associated with increased rates of APTC events. Study data are compatible with an early increase in risk that persists for one year after stopping treatment