17 research outputs found
Geometric tree kernels: Classification of COPD from airway tree geometry
Methodological contributions: This paper introduces a family of kernels for
analyzing (anatomical) trees endowed with vector valued measurements made along
the tree. While state-of-the-art graph and tree kernels use combinatorial
tree/graph structure with discrete node and edge labels, the kernels presented
in this paper can include geometric information such as branch shape, branch
radius or other vector valued properties. In addition to being flexible in
their ability to model different types of attributes, the presented kernels are
computationally efficient and some of them can easily be computed for large
datasets (N of the order 10.000) of trees with 30-600 branches. Combining the
kernels with standard machine learning tools enables us to analyze the relation
between disease and anatomical tree structure and geometry. Experimental
results: The kernels are used to compare airway trees segmented from low-dose
CT, endowed with branch shape descriptors and airway wall area percentage
measurements made along the tree. Using kernelized hypothesis testing we show
that the geometric airway trees are significantly differently distributed in
patients with Chronic Obstructive Pulmonary Disease (COPD) than in healthy
individuals. The geometric tree kernels also give a significant increase in the
classification accuracy of COPD from geometric tree structure endowed with
airway wall thickness measurements in comparison with state-of-the-art methods,
giving further insight into the relationship between airway wall thickness and
COPD. Software: Software for computing kernels and statistical tests is
available at http://image.diku.dk/aasa/software.php.Comment: 12 page
A Combined Pulmonary Function and Emphysema Score Prognostic Index for Staging in Chronic Obstructive Pulmonary Disease
Chronic Obstructive Pulmonary Disease (COPD) is characterized by high morbidity and mortality. Lung computed tomography parameters, individually or as part of a composite index, may provide more prognostic information than pulmonary function tests alone.To investigate the prognostic value of emphysema score and pulmonary artery measurements compared with lung function parameters in COPD and construct a prognostic index using a contingent staging approach.Predictors of mortality were assessed in COPD outpatients whose lung computed tomography, spirometry, lung volumes and gas transfer data were collected prospectively in a clinical database. Univariate and multivariate Cox proportional hazard analysis models with bootstrap techniques were used.169 patients were included (59.8% male, 61.1 years old; Forced Expiratory Volume in 1 second % predicted: 40.5Âą19.2). 20.1% died; mean survival was 115.4 months. Age (HRâ=â1.098, 95% Clâ=â1.04-1.252) and emphysema score (HRâ=â1.034, 95% CIâ=â1.007-1.07) were the only independent predictors of mortality. Pulmonary artery dimensions were not associated with survival. An emphysema score of 55% was chosen as the optimal threshold and 30% and 65% as suboptimals. Where emphysema score was between 30% and 65% (intermediate risk) the optimal lung volume threshold, a functional residual capacity of 210% predicted, was applied. This contingent staging approach separated patients with an intermediate risk based on emphysema score alone into high risk (Functional Residual Capacity âĽ210% predicted) or low risk (Functional Residual Capacity <210% predicted). This approach was more discriminatory for survival (HRâ=â3.123; 95% CIâ=â1.094-10.412) than either individual component alone.Although to an extent limited by the small sample size, this preliminary study indicates that the composite Emphysema score-Functional Residual Capacity index might provide a better separation of high and low risk patients with COPD, than other individual predictors alone
Usefulness of the âSpine Signâ on lateral chest radiographs
info:eu-repo/semantics/nonPublishe
Une occlusion intestinale inhabituelle.
Malignant melanoma is a rapidly metastatic disease. Metastasis in the small intestine is as such not uncommon, whereas the clinical presentation of obstruction due to intussusception is very rare. We hereafter report the case of a 58-year-old female admitted with general degradation, syndrome of intestinal occlusion and a cervical mass. Imaging studies showed signs suggesting an invagination of the small intestine. A resection of the cervical mass and segmental small intestine resection were performed. Pathological findings revealed a cervical malignant melanoma spread into the small intestine. The diagnosis of intestinal metastasis should therefore be considered in patients with intestinal occlusion and history of melanoma and presenting gastrointestinal symptoms.info:eu-repo/semantics/publishe