Narrow Band Imaging Endoscopy for the Detection of Dysplastic and Non Dysplastic Barrett's Esophagus

Abstract

The distribution of metaplastic (IM) and dysplastic epithelium within the Barrett's esophagus (BE) segment is patchy requiring random biopsies. The use of new techniques to identify these high yield areas would be helpful.The sequential lighting method in video endoscopes have a rotation disk with RGB (red,green,blue) optical filters in front of a white light source (xenon lamp). Narrow Band Imaging (NBI) is a novel technique which changes these optical filters to spectral narrow band filters. The penetration depth of light is dependent on its wavelength with visible blue light penetrating only superficial areas of the tissue. Therefore, use of blue light with the help of a special NB filter (415 nm, 445 nm, 500 nm) will enable imaging of the superficial tissue structures. AIM: To study the clinical utility of NBI endoscopy in pts with suspected BE. METHODS: Patients suspected with BE were studied with a standard magnification endoscope (Olympus GIF 240Z,115×) using a NBI light source. NBI endoscopy provided a striking contrast between the squamous and columnar mucosa in the distal esophagus without dye spraying. Specific capillary and mucosal patterns within the BE segment were identified, biopsied and read by pathologists blinded to endoscopic findings. RESULTS: 51 patients with a mean age of 64 years (range: 43-85 yrs) and a mean BE length of 3.5 cms (range: 0.5-16 cms) have been studied using NBI. 24 patients had IM without dysplasia,10 had low grade dysplasia (LGD), 9 had high grade dysplasia (HGD) and 8 without IM/dysplasia. All patients with IM without dysplasia had a fine capillary pattern showing a normal size, shape and distribution of small blood vessels and a ridge/villous mucosal pattern; whereas all 9 HGD patients had an abnormal capillary pattern- increased number, tortous, dilated, corkscrew type small blood vessels. All except 1 LGD patient had a similar pattern as IM. The sensitivity and specificity of the ‘normal capillary pattern’ to rule out HGD were 97.8% and 100% respectively; whereas it's sensitivity and specificity to detect non dysplastic tissue were 100% and 53% respectively. All long BE and 71% of short BE patients were identified with NBI. CONCLUSIONS: By changing the spectral feature of the observation light, NBI endoscopy provides a high quality and sharp contrast image of the BE segment without using dye spray (chromoscopy). It also provides a detailed image of the capillary and mucosal patterns in BE patients with a high accuracy for the detection of dysplastic and non dysplastic tissue.