Narrow band imaging for early diagnosis of epithelial dysplasia and microinvasive tumors in the upper aerodigestive tract

The various stages of tumor growth are characterized by typical epithelial, vascular, and secondary connective tissue changes. Narrow Band Imaging (NBI) endoscopy is a minimally invasive imaging technique that presents vascular structures in particular at a higher contrast than white light endoscopy alone. In combination with high-resolution image recording and reproduction (high-definition television, HDTV; ultra-high definition, 4K), progress has been made in otolaryngological differential diagnostics, both pre- and intraoperatively. This progress represents an important step toward a so-called optical biopsy. Flexible endoscopy in combination with NBI allows for a detailed assessment of areas of the upper aerodigestive tract that are difficult to assess by rigid endoscopy. Papillomas along with precancerous and cancerous lesions are characterized by epithelial and connective tissue changes as well as by typical perpendicular vascular changes. Systematic use of NBI is recommended in the differential diagnosis of malignant lesions of the upper aerodigestive tract. NBI also offers a significant improvement in the pre- and intraoperative assessment of superficial resection margins. In particular, the combination of NBI and contact endoscopy (compact endoscopy) facilitates excellent therapeutic decisions during tumor surgery. Intraoperative determination of resection margins at an unprecedented precision is possible. In addition, assessment of the form and extent of the perpendicular vessel loops stimulated by epithelial signaling enables differential diagnostic decisions to be made, approximating our goal of an optical biopsy.