Evaluation Of Image Quality Over Time After Injection Of The Fluorescein Sodium For Confocal Laser Endomicroscopy In Human

BackgroundConfocal laser endomicroscopy (CLE) is a newly developed endoscopic imaging technique which helps us get histopathologic diagnosis without biopsy during ongoing endoscopy and allows targeted biopsies. Fluorescein sodium is the most widely used to optimize imaging with CLE. A recent test estimated that fluorescein-based confocal laser scanning microscopy (CLSM) of the upper-GI tract of pigs delivers the best contrast and image quality within the first 8 minutes after injection of fluorescein. However, despite its increasing use in clinical examination recently, there are no data on image quality over time after injection of the fluorescein sodium in the inspection of gastrointestinal tract of human being.ObjectiveTo estimate the ideal time period during which the best CLE imaging can be produced after injection of fluorescein sodium in the GI of human.Materials and methodsPatients:Eighteen patients (eleven female) with age ranging from 18 to 60 years were enrolled in the study. Patients with normal stomach under standard endoscopy and confocal laser endomicroscopy, were involved.Patients exclusion criteria were as follows:below 18 or above 60 years of age; a history of bronchial asthma, or known allergy to fluorescein sodium; severe inflammation of the stomach; pregnant or breast-feeding; non-correctable coagulopathy; severe comorbidities (e.g. such as renal failure, congestive cardiac failure, liver cirrhosis).All procedures were performed using a Pentax EC3870K endomicroscope (Pentax, Tokyo, Japan). After injection of 5～10ml of 0.1g/ml fluorescein sodium, consecutive CLE images of the antral greater curvature of stomach were recorded after 1,3,5,8,10,15,20, and 30 minutes.Objective evaluation:Images analysis includes objective evaluation and subjective evaluation..5 pictures of each patient at respective time point were analysed with histograms to note the mean gray value (MGV), standard deviation (SD) and signal-to-noise ratio (SNR) as objective evaluation. A total of 545 images were analyzed.Subjective evaluation:10 images per time period were put into a random order and then blindly evaluated by 2 endoscopists:one evaluator had ample experience on the CLE (E.C), and another did not (I.C.).Results were graded on a 5-point scale. The highest number corresponded to best image quality. Rating based on the evaluator's subjective impression on image quality. Furthermore, E.C dentified whether these images meet needs for diagnosis.Results:There are no significantly difference in value of mean gray value and standard deviation between 3 minutes and 5 minutes (P>0.05),.and value of mean gray value and standard deviation decrease obviously over time after 15mins. Subjective evaluation demonstrated the same result. A total of 11 pictures were selected by reviewers (E.C.) can not be used for diagnosis. This distribution is:7 images at 30min, 2 images at 20min,1 image at 10min and 1 image at 5min.Conclusions:1.During inspection with CLE, we can get the best image quality within the first 5 minutes after injection of the fluorescein sodium.2. The images we obtain within the first 15 minutes after injection of the fluorescein sodium can meet the needs for diagnosis.3. The examination of CLE should last for no more than 30 minutes.