Clinically Available Optical Imaging Technologies in Endoscopic Lesion Detection: Current Status and Future Perspective

Abstract

Endoscopic optical imaging technologies for the detection and evaluation of dysplasia and early cancer have made great strides in recent decades. With the capacity of in vivo early detection of subtle lesions, they allow modern endoscopists to provide accurate and effective optical diagnosis in real time. This review mainly analyzes the current status of clinically available endoscopic optical imaging techniques, with emphasis on the latest updates of existing techniques. We summarize current coverage of these technologies in major hospital departments such as gastroenterology, urology, gynecology, otolaryngology, pneumology, and laparoscopic surgery. In order to promote a broader understanding, we further cover the underlying principles of these technologies and analyze their performance. Moreover, we provide a brief overview of future perspectives in related technologies, such as computer-assisted diagnosis (CAD) algorithms dealing with exploring endoscopic video data. We believe all these efforts will benefit the healthcare of the community, help endoscopists improve the accuracy of diagnosis, and relieve patients’ suffering.

Role of Macroscopic Image Enhancement in Diagnosis of Non-Muscle-Invasive Bladder Cancer: An Analytical Review

“…Macroscopic technologies are also called “wide field view.” In this, a surgeon diagnoses a lesion looking at mucosal morphology, color, and vessels. Macroscopic imaging identifies ulcers, erosions, papillary lesions, reddish or white spots, and the presence of vessels in the mucosa and neo-angiogenesis ( 10 ). Macroscopic techniques are further classified as wide-field WLI or contrast enhancement techniques.…”

“…Newer systems with 4 and 8K (UHD) are being used nowadays. Wide-field endoscopy also uses enhancement modalities like close focus, dual focus, optical zoom, and electronic zoom to gain better vision and have a low rate of missed lesions ( 10 ). Data on the impact of wide-field WLI on improved diagnosis and better outcomes in bladder cancer is awaited.…”

“…Herein, either incident light is changed to selected waveforms or images generated after illumination are processed to transform color or change color tone, or change the contrast. Based on the stage of processing of light, VCE is further classified into three categories: pre-processing, post-processing, pre- and post-processing ( 10 ).…”

“…Fluorescence signals emitted by fluorophores are dependent on wavelength. There are special optical fibers used in this system that block the false excitation of light and capture only a part of the emitted light, thereby producing a final image ( 10 ). Commonly used fluorescence endoscopy techniques are autofluorescence imaging (AFI), near-infrared imaging (NIR) with indocyanine green (ICG), and photodynamic diagnosis (PDD).…”

“…Carcinoma in situ, an aggressive variety of urothelial cancer, would certainly be seen in an efficient manner because of a characteristic appearance based on higher vascularity. Initial primary versions of NBI scopes had relatively lesser illumination than white light, making it difficult to be used as the primary method of diagnosis; however, in 2013, secondgeneration NBI scopes (EVIS LUCERA ELITE and EVIS EXERA III, Olympus) were manufactured and had high illumination intensity (10). In the third-generation NBI system (EVIS X1), Olympus, Japan designed two LED lights with specific central wavelengths of 460 and 540 nm to provide a narrow bandwidth (10).…”