k-Nearest Neighbor Curves in Imaging Data Classification

Background: Lung disease quantification via medical image analysis is classically difficult. We propose a method based on normalized nearest neighborhood distance classifications for comparing individual CT scan air-trapping distributions (representing 3D segmented parenchyma). Previously, between-image comparisons were precluded by the variation inherent to parenchyma segmentations, the dimensions of which are patient- and image-specific by nature.Method: Nearest neighbor distance estimations are normalized by a theoretical distance according to the uniform distribution of air trapping. This normalization renders images (of different sizes, shapes, and/or densities) comparable. The estimated distances for the k-nearest neighbor describe the proximity of point patterns over the image. Our approach assumes and requires a defined homogeneous space; therefore, a completion pretreatment is applied beforehand.Results: Model robustness is characterized via simulation in order to verify that the required initial transformations do not bias uniformly sampled results. Additional simulations were performed to assess the discriminant power of the method for different point pattern profiles. Simulation results demonstrate that the method robustly recognizes pattern dissimilarity. Finally, the model is applied on real data for illustrative purposes.Conclusion: We demonstrate that a parenchyma-cuboid completion method provides the means of characterizing air-trapping patterns in a chosen segmentation and, importantly, comparing such patterns between patients and images

The HDAC inhibitor SAHA does not rescue CFTR membrane expression in Cystic Fibrosis

International audienc

Mucus Microrheology Measured on Human Bronchial Epithelium Culture

We describe an original method to measure mucus microrheology on human bronchial epithelium culture using optical tweezers. We probed rheology on the whole thickness of mucus above the epithelium and showed that mucus gradually varies in rheological response, from an elastic behavior close to the epithelium to a viscous one far away. Microrheology was also performed on mucus collected on the culture, on ex vivo mucus collected by bronchoscopy, and on another epithelium model. Differences are discussed and are related to mucus heterogeneity, adhesiveness, and collection method

Rising total costs and mortality rates associated with admissions due to COPD exacerbations

International audienceTo examine trends in mortality, costs and in-hospital management and outcomes of severe COPD exacerbations admitted in France.Not applicable

Remodelage bronchique dans l’asthme

L’asthme est caractérisé par une inflammation chronique des voies aériennes associée à une hyperactivité bronchique et des modifications structurales de la paroi bronchique. Le déclin de la fonction respiratoire des asthmatiques est accéléré et certains patients ne sont plus capables de normaliser leurs capacités fonctionnelles. On explique ces anomalies persistantes par des modifications structurales de la paroi bronchique que l’on désigne sous l’appellation remodelage bronchique. Ce remodelage inclut des altérations de l’épithélium avec une hyperplasie des cellules à mucus et une fragilité des cellules épithéliales, une fibrose sous-épithéliale avec modifications de la matrice extracellulaire, une hypertrophie des cellules musculaires lisses bronchiques et une hyperplasie des vaisseaux sanguins, des nerfs et des glandes de la sous-muqueuse bronchique. Ces phénomènes sont peut-être les conséquences d’un processus de réparation mal maîtrisé, en particulier dans l’asthme sévère, en association avec la persistance d’une inflammation chronique. Ces anomalies sont associées à la chronicité et à la sévérité de l’asthme. Une prise en charge précoce, utilisant des traitements modifiant ces anomalies, pourrait être le garant d’une « guérison » de l’asthme léger et d’un meilleur contrôle de l’asthme sévère