Mr-Nom: Multi-Scale Resolution of Neuronal Cells in Nissl-Stained Histological Slices Via Deliberate over-Segmentation and Merging

In comparative neuroanatomy, the characterization of brain cytoarchitecture is critical to a better understanding of brain structure and function, as it helps to distill information on the development, evolution, and distinctive features of different populations. The automatic segmentation of individual brain cells is a primary prerequisite and yet remains challenging. A new method (MR-NOM) was developed for the instance segmentation of cells in Nissl-stained histological images of the brain. MR-NOM exploits a multi-scale approach to deliberately over-segment the cells into superpixels and subsequently merge them via a classifier based on shape, structure, and intensity features. The method was tested on images of the cerebral cortex, proving successful in dealing with cells of varying characteristics that partially touch or overlap, showing better performance than two state-of-the-art methods

Microcirugía de glaucoma con el implante Preserflo : fluídica experimental, morfología de la ampolla de filtración, cambios biométricos y corneales

Tesis inédita de la Universidad Complutense de Madrid, Facultad de Medicina, leída el 30-06-2022La reducción de la presión intraocular (PIO) ha demostrado ser el único tratamiento válido del glaucoma, principal causa de ceguera irreversible en el mundo. En un estudio reciente realizado por GBD 2019 Blindness and Vision Impairment Collaborators, en 2020 la segunda causa principal de ceguera mundial entre los 33,6 millones de ciegos mayores de 50 años fue el glaucoma (3,6 millones de casos, rango 2,8 a 4,4), por detrás de las cataratas. Aunque la técnica quirúrgica de referencia para el tratamiento del glaucoma es la trabeculectomía, descrita y aplicada desde mediados de la década de los 60´, actualmente se vienen desarrollando nuevos métodos quirúrgicos menos invasivos cuyo objetivo es reducir las complicaciones. Entre ellos, uno de los dos nuevos dispositivos de microcirugía filtrante de glaucoma es el implante Preserflo (Santen Pharmaceutical Company Ltd, Osaka, Japón). Este dispositivo consiste en un tubo de drenaje de humor acuoso diseñado para ser implantado ab externo mediante la disección de la conjuntiva y de la cápsula de Tenon. El objetivo de este implante sería el de comunicar la cámara anterior con el espacio subconjuntival, creando una corriente contínua de humor acuoso hacia el plexo venoso epiescleral...The reduction of intraocular pressure (IOP) has been proved the only valid treatment for glaucoma, which is the main cause for irreversible blindness worldwide. In a recent study carried outby the GBD 2019 Blindness and Vision Impairment Collaborators, among the global 33.6 million adults aged 50 years and older who were blind in 20203 the second leading cause of blindness was glaucoma (3.6 million cases, ranging from 2.8 to 4.4) after cataract. The gold standard for glaucoma surgery is trabeculectomy, described and applied since the mid-1960s,but new surgical methods less invasive have been developed in order to reduce adverse events. One of the two micro-filtering glaucoma surgery devices available in the market is the Preserflo Microshunt (Santen Pharmaceutical Company Ltd, Osaka, Japan). This is an aqueous drainage shunt to be implanted ab externo to create a full-thickness fistula from the anterior chamber across to the subconjunctival space...Fac. de MedicinaTRUEunpu

Corneal Endothelial Cell Segmentation by Classifier-driven Merging of Oversegmented Images

Corneal endothelium images obtained by in vivo specular microscopy provide important information to assess the health status of the cornea. Estimation of clinical parameters, such as cell density, polymegethism, and pleomorphism, requires accurate cell segmentation. State-of-the-art techniques to automatically segment the endothelium are error-prone when applied to images with low contrast and/or large variation in cell size. Here, we propose an automatic method to segment the endothelium. Starting with an oversegmented image comprised of superpixels obtained from a stochastic watershed segmentation, the proposed method uses intensity and shape information of the superpixels to identify and merge those that constitute a cell, using Support Vector Machines. We evaluated the automatic segmentation on a dataset of in vivo specular microscopy images (Topcon SP-1P), obtaining 95.8merged cells and 2.0the parameter estimation against the results of the vendor’s builtin software, obtaining a statistically significant better precision in all parameters and a similar or better accuracy. The parameter estimation was also evaluated on three other datasets from different imaging modalities (confocal microscopy, phasecontrast microscopy, and fluorescence confocal microscopy) and tissue types (ex vivo corneal endothelium and retinal pigment epithelium). In comparison with the estimates of the datasets’ authors, we achieved statistically significant better accuracy and precision in all parameters except pleomorphism, where a similar accuracy and precision were obtained.ImPhys/Quantitative ImagingApplied Science