Читать книгу The Esophagus - Группа авторов - Страница 204

John A. Dumot1, John J. Vargo2, and Arvind J. Trindade3

1 University Hospitals of Cleveland and Case Western Reserve University, Cleveland, OH, USA

2 Cleveland Clinic, Cleveland, OH, USA

3 Long Island Jewish Medical Center, New Hyde Park, NY; Zucker School of Medicine at Hofstra/Northwell

The role of visual identification of lesions and mucosal patterns is fundamental to the diagnosis of esophageal conditions. High‐definition white light endoscopy is the practice standard for all diagnostic and screening endoscopic exams. Special endoscopic imaging and optical techniques refer to technical developments beyond standard high‐definition. Some of these enhanced techniques are readily available at your fingertips with modern endoscopes. Other methods require topical or intravascular agents that interact with the lumen surface or enhance the vascular anatomy. Further enhancement has been found with laser techniques, which allow visualization of cellular structure. Specific mucosal and vascular patterns should prompt mucosal biopsies in the identification of dysplasia and neoplasia because early diagnosis is associated with high cure rates with endoscopic and surgical therapies.

Early neoplasia can occur in flat mucosa as well as appear elevated or depressed. Identification of neoplasia in flat mucosa requires a high index of suspicion. Dedicating time to learn the techniques of high‐quality examinations and applying it to your practice yields better outcomes. The rate of dysplasia detection seems to be directly related to the time observing the Barrett’s esophagus (BE) segment. Learning to slow down and pay attention can be one of the most satisfying opportunities in a time when we have an unprecedented number of tasks before and after endoscopic exams. In a post hoc analysis of 112 patients undergoing surveillance by 11 physicians, Gupta et al. found an inflection point in the rate of detecting suspicious lesions (54.2% vs. 13.3%; P = 0.04) and high‐grade dysplasia or adenocarcinoma (40.2% vs. 6.7%; P = 0.06) when an average of one minute of observation time per centimeter of BE length was reached [1]. Clearly, longer examination times are needed in longer segments of BE in order to correctly identify visible lesions, which will prompt dedicated biopsies or mucosal resection of those areas.

The standard of care is now high‐definition video images with a depth of field generally between 2 mm and 100 mm. Clear images of the mucosal surface pit pattern and microvascular architecture help identify areas of irregularity, which are more likely to represent areas of dysplasia. Some manufacturers have models with built‐in near field focus to give a zoom appearance. Further developments have introduced ultra‐high magnification up to 520×, allowing direct observation of cellular nuclei with staining and scattered light reflected back into the objective lens (EVIS Lucera Elite series, Olympus, Tokyo). The field of view is obviously narrow, so this technology has utility when there is a target lesion to study. The future holds promise for other developing technologies, including auto‐florescence imaging (AFI) that utilizes fluorescence intensity to differentiate areas of dysplasia and neoplasia in a wider field [2].

Friction‐fit soft caps are one of the most useful devices to stabilize the endoscope anywhere along the esophageal lumen in order to enhance the quality of the image. The cost and limitation of view are slight drawbacks when evaluating a patient suspected of having dysplastic changes when an irregularity is identified during the exam or prior biopsy results raises the clinical suspicion of dysplasia or early neoplasia. Systematic biopsy of BE remains the standard for surveillance protocols because a significant number of neoplastic areas are in nonvisible areas of flat mucosa [3]. Unlike BE, squamous cell dysplasia has no useful biopsy pattern because the entire esophagus could be at risk for dysplasia, and therefore, physicians must rely on chromoendoscopy to identify areas to direct biopsies.