127 research outputs found
Stain Consistency Learning: Handling Stain Variation for Automatic Digital Pathology Segmentation
Stain variation is a unique challenge associated with automated analysis of
digital pathology. Numerous methods have been developed to improve the
robustness of machine learning methods to stain variation, but comparative
studies have demonstrated limited benefits to performance. Moreover, methods to
handle stain variation were largely developed for H&E stained data, with
evaluation generally limited to classification tasks. Here we propose Stain
Consistency Learning, a novel framework combining stain-specific augmentation
with a stain consistency loss function to learn stain colour invariant
features. We perform the first, extensive comparison of methods to handle stain
variation for segmentation tasks, comparing ten methods on Masson's trichrome
and H&E stained cell and nuclei datasets, respectively. We observed that stain
normalisation methods resulted in equivalent or worse performance, while stain
augmentation or stain adversarial methods demonstrated improved performance,
with the best performance consistently achieved by our proposed approach. The
code is available at: https://github.com/mlyg/stain_consistency_learnin
Um Interior Vazio: A análise da situação dos municípios do COREDE Fronteira Noroeste
Um dos fatores que influenciam o desenvolvimento local é a dinâmica populacional. O deslocamento de pessoas para uma determinada área está relacionado com o comportamento da economia e, a análise das conexões entre migração e desenvolvimento se torna pertinente. O Conselho Regional de Desenvolvimento (COREDE) Fronteira Noroeste é o objeto desta pesquisa devido à evasão populacional que se verifica em seu território, sobretudo nos municípios de menor porte. Esta investigação busca despertar uma reflexão sobre as causas e as soluções para este problema de modo que, o aprofundamento deste estudo contribui para o entendimento dos movimentos migratórios e o desenvolvimento. One of the factors that influence local development is the population dynamics. The movement of people to a particular area is related to the behavior of the economy and the analysis of the links between migration and development becomes relevant. The Regional Development Council (COREDE) North West Frontier is the object of this research due to the decline in population that occurs in its territory, particularly in smaller municipalities. This research seeks to arouse a reflection on the causes and solutions to this problem so that the deepening of this study contributes to the understanding of migration and development
Efficient Post-processing of Diffusion Tensor Cardiac Magnetic Imaging Using Texture-conserving Deformable Registration
Diffusion tensor based cardiac magnetic resonance (DT-CMR) is a method
capable of providing non-invasive measurements of myocardial microstructure.
Image registration is essential to correct image shifts due to intra and inter
breath-hold motion. Registration is challenging in DT-CMR due to the low
signal-to-noise and various contrasts induced by the diffusion encoding in the
myocardial and surrounding organs. Traditional deformable registration destroys
the texture information while rigid registration inefficiently discards frames
with local deformation. In this study, we explored the possibility of deep
learning-based deformable registration on DT- CMR. Based on the noise
suppression using low-rank features and diffusion encoding suppression using
variational auto encoder-decoder, a B-spline based registration network
extracted the displacement fields and maintained the texture features of
DT-CMR. In this way, our method improved the efficiency of frame utilization,
manual cropping, and computational speed.Comment: 4 pages, 4 figures, conferenc
Frequency of ABCA4 mutations in 278 Spanish controls: an insight into the prevalence of autosomal recessive Stargardt disease
Diffusion tensor MRI of the human heart In Vivo with a navigator based free breathing approach
Assessment of myocardial microstructural dynamics by in vivo diffusion tensor cardiac magnetic resonance
Background: Cardiomyocytes are organized in microstructures termed sheetlets that reorientate during left ventricular thickening. Diffusion tensor cardiac magnetic resonance (DT-CMR) may enable noninvasive interrogation of in vivo cardiac microstructural dynamics. Dilated cardiomyopathy (DCM) is a condition of abnormal myocardium with unknown sheetlet function.
Objectives: This study sought to validate in vivo DT-CMR measures of cardiac microstructure against histology, characterize microstructural dynamics during left ventricular wall thickening, and apply the technique in hypertrophic cardiomyopathy (HCM) and DCM.
Methods: In vivo DT-CMR was acquired throughout the cardiac cycle in healthy swine, followed by in situ and ex vivo DT-CMR, then validated against histology. In vivo DT-CMR was performed in 19 control subjects, 19 DCM, and 13 HCM patients.
Results: In swine, a DT-CMR index of sheetlet reorientation (E2A) changed substantially (E2A mobility ∼46°). E2A changes correlated with wall thickness changes (in vivo r2 = 0.75; in situ r2 = 0.89), were consistently observed under all experimental conditions, and accorded closely with histological analyses in both relaxed and contracted states. The potential contribution of cyclical strain effects to in vivo E2A was ∼17%. In healthy human control subjects, E2A increased from diastole (18°) to systole (65°; p < 0.001; E2A mobility = 45°). HCM patients showed significantly greater E2A in diastole than control subjects did (48°; p < 0.001) with impaired E2A mobility (23°; p < 0.001). In DCM, E2A was similar to control subjects in diastole, but systolic values were markedly lower (40°; p < 0.001) with impaired E2A mobility (20°; p < 0.001).
Conclusions: Myocardial microstructure dynamics can be characterized by in vivo DT-CMR. Sheetlet function was abnormal in DCM with altered systolic conformation and reduced mobility, contrasting with HCM, which showed reduced mobility with altered diastolic conformation. These novel insights significantly improve understanding of contractile dysfunction at a level of noninvasive interrogation not previously available in humans
Molecular analysis of the ABCA4 gene for reliable detection of allelic variations in Spanish patients: identification of 21 novel variants
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