Subject: myelin
Subject: measurement
Subject: electron micrographs
Subject: axon
Year: 2019
Type: Article
Title: Measurement-oriented deep-learning workflow for improved segmentation of myelin and axons in high-resolution images of human cerebral white matter
Author: Janjic, Predrag
Author: Petrovski, Kristijan
Author: Dolgoski, Blagoja
Author: Smiley, John
Author: Zdravkovski, Panche
Author: Pavlovski, Goran
Author: Jakjovski, Zlatko
Author: Davcheva, Natasha
Author: Poposka, Verica
Author: Stankov, Aleksandar
Author: Rosoklija, Gorazd
Author: Petrushevska, Gordana
Author: Kocarev, Ljupcho
Author: Dwork, Andrew J.
Abstract: Background: Standard segmentation of high-contrast electron micrographs (EM) identifies myelin accurately but does not translate easily into measurements of individual axons and their myelin, even in cross-sections of parallel fibers. We describe automated segmentation and measurement of each myelinated axon and its sheath in EMs of arbitrarily oriented human white matter from autopsies. New methods: Preliminary segmentation of myelin, axons and background by machine learning, using selected filters, precedes automated correction of systematic errors. Final segmentation is done by a deep neural network (DNN). Automated measurement of each putative fiber rejects measures encountering pre-defined artifacts and excludes fibers failing to satisfy pre-defined conditions. Results: Improved segmentation of three sets of 30 annotated images each (two sets from human prefrontal white matter and one from human optic nerve) is achieved with a DNN trained only with a subset of the first set from prefrontal white matter. Total number of myelinated axons identified by the DNN differed from expert segmentation by 0.2%, 2.9%, and -5.1%, respectively. G-ratios differed by 2.96%, 0.74% and 2.83%. Intraclass correlation coefficients between DNN and annotated segmentation were mostly>0.9, indicating nearly interchangeable performance. Comparison with existing method(s): Measurement-oriented studies of arbitrarily oriented fibers from central white matter are rare. Published methods are typically applied to cross-sections of fascicles and measure aggregated areas of myelin sheaths and axons, allowing estimation only of average g-ratio. Conclusions: Automated segmentation and measurement of axons and myelin is complex. We report a feasible approach that has so far proven comparable to manual segmentation.
Publisher: Elsevier BV
Relation: Journal of Neuroscience Methods
Identifier: oai:repository.ukim.mk:20.500.12188/17775
Identifier: http://hdl.handle.net/20.500.12188/17775Identifier: 10.1016/j.jneumeth.2019.108373
Identifier: https://api.elsevier.com/content/article/PII:S0165027019302304?httpAccept=text/xmlIdentifier: https://api.elsevier.com/content/article/PII:S0165027019302304?httpAccept=text/plainIdentifier: 326
Identifier: 108373
