Endomicroscopy imaging of epithelial structures using tissue autofluorescence

Functional endoscopy techniques for tracking stem cell fate

Tracking and monitoring implanted stem cells are essential to maximize benefits and to minimize the side effects of stem cell therapy for personalized or "precision" medicine. Previously, we proposed a comprehensive biological Global Positioning System (bGPS) to track and monitor stem cells in vivo. Magnetic resonance imaging (MRI), positron emission tomography (PET), bioluminescent imaging, fluorescence imaging, and single-photon emission computerized tomography (SPECT) have been utilized to track labeled or genetically-modified cells in vivo in rats and humans. A large amount of research has been dedicated to the design of reporter genes and molecular probes for imaging and the visualization of the biodistribution of the implanted cells in high resolution. On the other hand, optical-based functional imaging, such as photoacoustic imaging (PAI), optical coherence tomography (OCT), and multiphoton microscopy (MPM), has been implemented into small endoscopes to image cells inside the body. The optical fiber allows miniaturization of the imaging probe while maintaining high resolution due to light-based imaging. Upon summarizing the recent progress in the design and application of functional endoscopy techniques for stem cell monitoring, we offer perspectives for the future development of endoscopic molecular imaging tools for in vivo tracking of spatiotemporal changes in subclonal evolution at the single cell level.

Evaluation of dual-wavelength excitation autofluorescence imaging of colorectal tumours with a high-sensitivity CMOS imager: a cross-sectional study

Background

It is important to devise efficient and easy methods of detecting colorectal tumours to reduce mortality from colorectal cancer. Dual-wavelength excitation autofluorescence intensity can be used to visualize colorectal tumours. Therefore, we evaluated dual-wavelength excitation autofluorescence images of colorectal tumours obtained with a newly developed, high-sensitivity complementary metal-oxide-semiconductor (CMOS) imager.

Methods

A total 107 colorectal tumours (44 adenomas, 43 adenocarcinomas with intramucosal invasion, and 20 sessile serrated adenoma/polyps [SSA/Ps]) in 98 patients who underwent endoscopic tumour resection were included. The specimens were irradiated with excitation light at 365 nm and 405 nm, and autofluorescence images measured with a 475 ± 25-nm band pass filter were obtained using a new, high-sensitivity CMOS imager. Ratio images (F365ex/F405ex) were created to evaluate the lesion brightness compared with that of normal mucosa, and specimens were categorized into a no signal or high signal group.

Results

Adenomas and adenocarcinomas were depicted in 87 ratio images, with 86.2 % (n = 75) in the High signal group. SSA/P was depicted in 20 ratio images, with 70.0 % (n = 14) in the High signal group.

Conclusions

Dual-wavelength excitation autofluorescence images of colorectal tumours can be acquired using our high-sensitivity CMOS imager, and are useful in detecting colorectal tumours.

Establishment of rules for interpreting ultraviolet autofluorescence microscopy images for noninvasive detection of Barrett's esophagus and dysplasia

The diagnostic potential of autofluorescence (AF) microscopy under ultraviolet (UV) excitation is explored using ex vivo human specimens. The aim is to establish optical patterns (the rules for interpretation) that correspond to normal and abnormal histologies of the esophagus, spanning from early benign modifications (Barrett's esophagus) to subsequent dysplastic change and progression toward carcinoma. This was achieved by developing an image library categorized by disease progression. We considered morphological changes of disease as they are compared with histological diagnosis of the pathological specimen, as well as control samples of normal esophagus, proximal stomach, and small intestine tissue. Our experimental results indicate that UV AF microscopy could provide real-time histological information for visualizing changes in tissue microstructure that are currently undetectable using conventional endoscopic methods.