The efficacy of autofluorescence imaging in the diagnosis of colorectal diseases

Abstract

Image-enhanced endoscopy (IEE) has been developed and is applied in the clinical setting throughout the world. Most reports regarding IEE have evaluated the efficacy of narrow-band imaging (NBI) in the diagnosis of gastrointestinal disorders. Although autofluorescence imaging (AFI) is a form of IEE, its usefulness remains unclear. The present review focused on the efficacy of AFI in the diagnosis of colorectal disease, particularly neoplasia and ulcerative colitis (UC). AFI-based diagnoses are made via the subjective judgment of the color on the monitor. The efficacy of AFI in detection and differentiation in patients with colorectal neoplastic lesions remains controversial, which may be dependent on the study design and the diagnostic procedures. Although the number of the reports related to UC is very small, most suggest that AFI is effective in UC patients. AFI is distinct from other modalities in that it can quantitatively assess the lesion based on the fluorescence intensity without any morphological assessments. AFI could be useful for patients with colorectal disease.Keywords Autofluorescence imaging (AFI) Á Colorectal neoplasia Á Ulcerative colitis (UC) Á Colitis-associated cancer Á Narrow-band imaging (NBI) Á Image-enhanced endoscopy (IEE) Á White light endoscopy (WLE)

Upcoming imaging concepts and their impact on treatment planning and treatment response in radiation oncology

“…Emitted autofluoresced light is detected by a camera and displayed onto a monitor for interpretation within the visible light spectrum [ 13 ]. Tissue fluorescence is determined by its molecular composition, so benign and malignant tissues can be differentiated based on their color and quantity of autofluorescence [ 14 ].…”

“…Systems implementing autofluorescence have already been incorporated into devices spanning several clinical applications, including bronchoscopy, colonic polyp evaluation, quantification of colonic inflammation, and intraoperative tumor evaluation [ 14 , 15 ]. Bronchoscopes with autofluorescent capabilities are currently being evaluated in cancer and precancerous lesion detection.…”

“…Per a recent review of upcoming imaging modalities, NIRF imaging may have the greatest potential for implementation in clinical practice in the near future [ 24 ]. Strengths of NIRF imaging include current FDA-approved imagers and dyes, deep depth-of-field (up to 4 cm), reduced image noise by native tissues and proteins, breadth of application with targeted dyes, and potential for real-time visualization [ 14 , 23 ]. Current drawbacks of NIRF imaging are the limited number of FDA-approved dyes, time requirement to properly administer dyes, need of an imaging device to visualize fluorophores, and inability to overlay images with a surgical field, which functionally blinds surgeons during image generation [ 14 , 23 ].…”

Capsule Endoscopy Compatible Fluorescence Imager Demonstrated Using Bowel Cancer Tumours

“…In AF endoscopy, fluorescence light is detected by exploiting the natural fluorescence of human tissues with blue light illumination [6]. Healthy areas will emit green autofluorescence while diseased areas will appear as darker regions [4], [7], [8].…”

Gastrointestinal diagnosis using non-white light imaging capsule endoscopy

“…Various studies have compared the efficacy of conventional AFI endoscopy to that of conventional WLI endoscopy 1 for the detection of gastrointestinal disease. Several of these studies have shown that AFI increases the detection 2 rate of diseases such as colorectal adenoma 75 and polyps 76 compared with WLI [75][76][77] . The efficacy of AFI in 3 diagnosing IBDs such as ulcerative colitis has also been examined.…”