Software for automated classification of probe-based confocal laser endomicroscopy videos of colorectal polyps

AIM:To support probe-based confocal laser endomi-croscopy (pCLE) diagnosis by designing software for the automated classification of colonic polyps. METHODS:Intravenous fluorescein pCLE imaging of colorectal lesions was performed on patients under-going screening and surveillance colonoscopies, followed by polypectomies. All resected specimens were reviewed by a reference gastrointestinal pathologist blinded to pCLE information. Histopathology was used as the criterion standard for the differentiation between neoplastic and non-neoplastic lesions. The pCLE video sequences, recorded for each polyp, were analyzed off-line by 2 expert endoscopists who were blinded to the endoscopic characteristics and histopathology. These pCLE videos, along with their histopathology diagnosis, were used to train the automated classification software which is a content-based image retrieval technique followed by k-nearest neighbor classification. The performance of the off-line diagnosis of pCLE videos established by the 2 expert endoscopists was compared with that of automated pCLE software classification. All evaluations were performed using leave-one-patient- out cross-validation to avoid bias. RESULTS:Colorectal lesions (135) were imaged in 71 patients. Based on histopathology, 93 of these 135 lesions were neoplastic and 42 were non-neoplastic. The study found no statistical significance for the difference between the performance of automated pCLE software classification (accuracy 89.6%, sensitivity 92.5%, specificity 83.3%, using leave-one-patient-out cross-validation) and the performance of the off-line diagnosis of pCLE videos established by the 2 expert endoscopists (accuracy 89.6%, sensitivity 91.4%, specificity 85.7%). There was very low power (< 6%) to detect the observed differences. The 95% confidence intervals for equivalence testing were:-0.073 to 0.073 for accuracy, -0.068 to 0.089 for sensitivity and -0.18 to 0.13 for specificity. The classification software proposed in this study is not a "black box" but an informative tool based on the query by example model that produces, as intermediate results, visually similar annotated videos that are directly interpretable by the endoscopist. CONCLUSION:The proposed software for automated classification of pCLE videos of colonic polyps achieves high performance, comparable to that of off-line diagnosis of pCLE videos established by expert endoscopists.

Erratum to “Optical Detection of Distal Lung Enzyme Activity in Human Inflammatory Lung Disease”

In the research article“Optical Detection of Distal Lung Enzyme Activity in Human Inflammatory Lung Disease”[1],the data availability statement was inadvertently omitted by the publisher.This has now been corrected in the PDF and HTML(full text).

Optical Detection of Distal Lung Enzyme Activity in Human Inflammatory Lung Disease

Objective and Impact Statement.There is a need to develop platforms delineating inflammatory biology of the distal human lung.We describe a platform technology approach to detect in situ enzyme activity and observe drug inhibition in the distal human lung using a combination of matrix metalloproteinase(MMP)optical reporters,fibered confocal fluorescence microscopy(FCFM),and a bespoke delivery device.Introduction.The development of new therapeutic agents is hindered by the lack of in vivo in situ experimental methodologies that can rapidly evaluate the biological activity or drug-target engagement in patients.Methods.We optimised a novel highly quenched optical molecular reporter of enzyme activity(FIB One)and developed a translational pathway for in-human assessment.Results.We demonstrate the specificity for matrix metalloproteases(MMPs)2,9,and 13 and probe dequenching within physiological levels of MMPs and feasibility of imaging within whole lung models in preclinical settings.Subsequently,in a first-in-human exploratory experimental medicine study of patients with fibroproliferative lung disease,we demonstrate,through FCFM,the MMP activity in the alveolar space measured through FIB One fluorescence increase(with pharmacological inhibition).Conclusion.This translational in situ approach enables a new methodology to demonstrate active drug target effects of the distal lung and consequently may inform therapeutic drug development pathways.