Advice
The technology
The technology
Narrow band imaging (NBI, Olympus) is an optical imaging technology that improves the visibility of vessels and other tissues on mucosal surfaces. It can be applied as part of a standard endoscopic examination. NBI is a part of the Evis Lucera Spectrum and Evis Lucera Elite endoscopy systems. It works by filtering the white light for specific light wavelengths that are absorbed by haemoglobin for maximum contrast. Using NBI, capillaries on the mucosal surface and veins in the submucosa are displayed in different colours on the endoscopist's monitor.
NBI can be used in several conditions, but this medtech innovation briefing focuses only on its use during both initial diagnostic endoscopy for people with suspected Barrett's oesophagus and as a monitoring tool for surveillance of patients with Barrett's oesophagus. Compared with white-light endoscopy, the images of capillaries seen when using NBI are more defined. This may reduce the possibility of missing an area of abnormal cells during endoscopy. During white-light endoscopy, random biopsies are taken to increase the diagnostic yield of neoplastic and dysplastic lesions. Using NBI allows areas to be identified for targeted biopsy and areas of normal tissue to be excluded by the endoscopist. The company claims the use of the technology could improve the real-time distinction between neoplastic or dysplasia lesions and surrounding non-neoplastic or non-dysplastic Barrett's tissue, reducing the need for histopathology because fewer biopsy samples are being taken.
Innovations
NBI uses an optical filter that limits light from 415 nm to 540 nm, matching the absorption spectrum of haemoglobin. While other technologies mainly focus on post-processing adjustments using software, NBI is an optical enhancement. There are other systems available that allow real-time assessment during endoscopy.
Current care pathway
Currently, people with suspected or known Barrett's oesophagus will have white-light endoscopy done by a doctor or specialist nurse. The current British Society of Gastroenterology guideline recommends the Seattle biopsy protocol, which includes 4-quadrant random biopsies every 2 cm as well as targeted biopsies on macroscopically-visible lesions at the time of diagnosis and at subsequent surveillance. It is reported that there is only slight discomfort and pain associated with this kind of biopsy. A variety of other imaging techniques may also be used to enhance visualisation of Barrett's oesophagus such as magnification, high-definition endoscopy and chromoendoscopy. However, expert advice suggests that these techniques are not routinely used in the NHS. Biopsies taken during an endoscopy are sent to histopathology where they are examined under a microscope to see if any abnormal cells are present, and to grade the extent of any abnormality.
When areas of abnormality are identified during an endoscopy, surveillance endoscopies can be recommended to monitor for further changes. In some cases, treatments to destroy or remove the abnormal cells and prevent them from progressing into cancer may be offered. NICE's guideline on Barrett's oesophagus describes the use of ablative therapy in people with high-grade dysplasia or intramucosal cancer. NICE has also published guidance on endoscopic radiofrequency ablation for Barrett's oesophagus with low-grade dysplasia or no dysplasia. Other treatment options include endoscopic mucosal resection, photodynamic therapy or surgical resection.
Population, setting and intended user
Barrett's oesophagus is a condition where the cells of the oesophagus grow abnormally and can develop into cancer over time. The most common cause of Barrett's oesophagus is acid reflux, which can inflame the oesophagus and may lead to a condition called gastro-oesophageal reflux disease (GORD). Around 3% to 10% of people with acid reflux will develop Barrett's oesophagus.
NBI can be used for first-time diagnosis of Barrett's oesophagus or for surveillance endoscopies in people with Barrett's oesophagus. The endoscopy will be done in a hospital by a doctor or specialist nurse. Additional training may be needed to make optical diagnoses and target biopsies with NBI.
Costs
Technology costs
The cost for NBI endoscopy is additional to the cost of white-light endoscopy, however the company estimates that costs for histopathology will be decreased if NBI is used.
The company states that the average cost per person for NBI endoscopy is £1,120, this includes histopathology costs of £348 per person.