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

Functional muscle impairment in facioscapulohumeral muscular dystrophy is correlated with oxidative stress and mitochondrial dysfunction

International audienceFacioscapulohumeral muscular dystrophy (FSHD),the most frequent muscular dystrophy, is an autosomal dominant disease. In most individuals with FSHD, symptoms are restricted to muscles of the face, arms, legs, and trunk. FSHD is genetically linked to contractions of the D4Z4 repeat array causing activation of several genes.One of these maps in the repeat itself and expresses the DUX4 (the double homeobox 4) transcription factor causing a gene deregulation cascade. In addition, analyses of the RNA or protein expression profiles in muscle have indicated deregulations in the oxidative stress response. Since oxidative stress affects peripheral muscle function, we investigated mitochondrial function and oxidative stress in skeletal muscle biopsies and blood samples from patients with FSHD and age-matched healthy controls, and evaluated their association with physical performances.We show that specifically, oxidative stress (lipid peroxidation and protein carbonylation), oxidative damage (lipofuscin accumulation), and antioxidant enzymes (catalase, copper–zinc-dependent super- oxide dismutase, and glutathione reductase) were higher in FSHD than in control muscles. FSHD muscles also presented abnormal mitochondrial function (decreased cytochrome c oxidase activity and reduced ATP synthesis). In addition, the ratio between reduced (GSH) and oxidized glutathione (GSSG) was strongly decreased in all FSHD blood samples as a consequence of GSSG accumulation. Patients with FSHD also had reduced systemic antioxidative response molecules, such as low levels of zinc (a SOD cofactor), selenium (a GPx cofactor involved in the elimination of lipid peroxides), and vitamin C. Half of them had a low ratio of gamma/alpha tocopherol and higher ferritin concentrations. Both systemic oxidative stress and mitochondrial dysfunction were correlated with functional muscle impairment. Mitochondrial ATP production was significantly correlated with both quadriceps endurance (TLimQ) and maximal voluntary contraction (MVCQ) values (rho¼0.79, P¼0.003; rho¼0.62, P¼0.05, respectively). The plasma concentration of oxidized glutathione was negatively correlated with the TLimQ, MVCQ values, and the 2-min walk distance (MWT) values (rho¼0.60, P¼0.03; rho¼0.56, P¼0.04; rho¼0.93, Po0.0001, respectively). Our data characterized oxidative stress in patients with FSHD and demonstrated a correlation with their peripheral skeletal muscle dysfunction. They suggest that antioxidants that might modulate or delay oxidative insult maybe useful in maintaining FSHD muscle functions

Feasibility and efficacy of early lung cancer diagnosis with chest computed tomography in HIV-infected smokers

International audienceOBJECTIVE: Lung cancer screening with chest computed tomography (CT) is beneficial in smokers aged 55 to 74 years. We studied the risks, benefits and feasibility of early lung cancer diagnosis with CT in HIV-infected smokers. DESIGN AND SETTING: French, multicentre, single round chest CT study in France, realized between February 2011 and June 2012. PARTICIPANTS: Patients were HIV-infected smokers at least 40 years, at least 20 pack-years, with a CD4 T-lymphocyte nadir count below 350 cells/μl. INTERVENTION: Single chest CT with a proposed standardized workup algorithm of positive images. MAIN OUTCOME MEASURE: The outcome was the number of histologically proven lung cancers diagnosed by CT with a 2-year follow-up. RESULTS: Median age of the 442 included patients was 49.8 years, 81.6% were under 55 years, 84% were men, median smoking was 30 pack-years, median nadir and last CD4 cell counts were 168 and 574 cells/μl, respectively, and 90% of patients had a plasma HIV RNA below 50 copies/ml. A positive image at baseline was reported in 94 (21%) patients, and 15 (3.4%) patients had 18 invasive procedures with no serious adverse events. Lung cancer was diagnosed in 10 patients (six at early stages), of which nine (2.0%, 95% confidence interval: 0.9-3.8) were CT detected, and eight in patients below 55 years. CONCLUSION: Early lung cancer diagnosis with CT in HIV-infected smokers was feasible, safe, and yielded a significant number of cancers. Lung cancer screening of HIV-infected smokers with an important history of immunodeficiency revealed a substantial number of cancers at younger ages than the targeted range in the general populatio

Evaluation de l'envahissement carotidien dans les carcinomes des voies aérodigestives supérieures

Les carcinomes des voies aérodigestives supérieures representent 90 % des tumeurs cervicales malignes. Au cours de leurs développements ces lésions peuvent envahir la paroi carotidienne, impliquant une prise en charge thérapeutique et un pronostic différent. Cet événement concerne 14% des évidements radicaux. La circonférence carotidienne au contact des adénopathies et la qualité du liseré graisseux péricarotidien ont été mesurées au scanner et rapportées à l'envahissement carotidien. Il existe un lien significatif entre circonférence et envahissement. Plus la circonférence est importante, plus le risque d'envahissement est élevé. Un contact entre les adénopathies et l'axe artériel inférieur à 90 de circonférence ainsi que le respect du liseré graisseux sont 2 critères prédictifs de l'absence d'envahissement. L'encerclement du vaisseau et la disparition du liseré sont suspects sans que l'on puisse affirmer l'envahissement de façon formelle.NANTES-BU Médecine pharmacie (441092101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Evaluation in vivo et in vitro d'un outil de segmentation bronchique en tomodensitométrie

MONTPELLIER-BU Médecine UPM (341722108) / SudocMONTPELLIER-BU Médecine (341722104) / SudocSudocFranceF

Software-assisted Computed Tomography Quantification of Airway Remodeling in the Normal Aging Process

International audienc

« Perception de la radiologie interventionnelle par les patients : enquête monocentrique »

International audienc

Lung cancer screening: French radiologists should prepare for it

International audienc

Complications with peripherally inserted central catheters (PICCs) used in hospitalized patients and outpatients: a prospective cohort study

Abstract Background Peripherally Inserted Central Catheters (PICCs) are widely used for hospitalized patients and among outpatients. Despite many advantages, PICC-related complications can occur such as infection, thrombosis or mechanical complications. We aimed to evaluate rates and nature of PICC-related complications from insertion to removal and analyze risk factors of complications at baseline and during healthcare. Methods We performed a prospective cohort study looking at PICC-related complication rates in the inpatient and outpatient settings of 163 patients over a 7-month period. Pertinent patient demographics as well as catheter-related factors were collected. The data were analyzed to identify catheter-related complications using univariate and multivariate analysis. Results One hundred ninety-two PICCs were monitored for a total of 5218 PICC-days (3337 PICC-days for inpatients, 1881 PICC-days for outpatients). The overall complication rate was 30.2% (11.1 per 1000 PICC-days) with a mean time to onset of 16.1 days. Complications included occlusion (8.9%), accidental withdrawal (8.9%), infections (6.3%) including 9 local infections (4.7%) and 3 bloodstream infections (1.6%), venous thrombosis (1.6%) and hematoma (1%). Complication rate was higher in the hospitalization setting (36.1%; 14.38 per 1000 PICC-days) than in the outpatient setting (19.4%; 3.19 per 1000 PICC-days). Multivariate logistic regression analysis showed that the occurrence of occlusion was significantly associated with an age > 65 years (OR = 4.19; 95% CI [1.1–15.81]) and the presence of a pre-occlusive event the week before PICC removal (OR = 76.35; 95% CI [9.36–622.97]). Conclusions PICCs appear safe in the inpatient and outpatient settings with low rates of infectious or thrombotic complications. Occlusion and accidental withdrawal were the most common complications, with age > 65 and catheter pre-occlusive event associated with an increased likelihood of catheter occlusion