231 research outputs found
Zien of raden?
Rede,
uitgesproken bij de aanvaarding
van het ambt van bijzonder hoogleraar
kinderpulmonologie, in het bijzonder
de ontwikkeling van de long,
aan het Erasmus MC, Faculteit van de
Erasmus Universiteit Rotterdam
op 12 februari 201
Annual lung function changes in young patients with chronic lung disease
Reference equations for ventilatory function that use different
statistical models may introduce artifacts that affect the estimated
change of lung function during growth in young subjects. The effect of
differently modelled reference equations on the estimated annual change of
forced expiratory volume in one second (FEV1) and forced vital capacity
(FVC) in young patients with chronic lung disease was assessed. Four
frequently used reference equations were used to describe the longitudinal
changes of FEV1 and FVC in 52 patients (23 females) with cystic fibrosis
(CF) during a mean follow-up of 3.9 yrs. Choice of reference equations
directly affected value and, most importantly, estimated annual change of
FVC and FEV1. Mean+/-SD annual change of FEV1 varied from 2.2+/-6.2 to
-2.2+/-3.6% of predicted. For two reference equations the estimated
individual changes of FEV1 and FVC in CF were positively correlated wit
Spectral Data Augmentation Techniques to quantify Lung Pathology from CT-images
Data augmentation is of paramount importance in biomedical image processing
tasks, characterized by inadequate amounts of labelled data, to best use all of
the data that is present. In-use techniques range from intensity
transformations and elastic deformations, to linearly combining existing data
points to make new ones. In this work, we propose the use of spectral
techniques for data augmentation, using the discrete cosine and wavelet
transforms. We empirically evaluate our approaches on a CT texture analysis
task to detect abnormal lung-tissue in patients with cystic fibrosis. Empirical
experiments show that the proposed spectral methods perform favourably as
compared to the existing methods. When used in combination with existing
methods, our proposed approach can increase the relative minor class
segmentation performance by 44.1% over a simple replication baseline.Comment: 5 pages including references, accepted as Oral presentation at IEEE
ISBI 202
Extra-fine particles improve lung delivery of inhaled steroids in infants: a study in an upper airway model
BACKGROUND: The particles of a new hydrofluoroalkane-134a
(HFA)-beclomethasone dipropionate (BDP) metered-dose inhaler (Qvar; 3M
Pharmaceuticals; St. Paul, MN) are considerably smaller than those of
chlorofluorocarbon (CFC)-BDP. This may improve lung deposition in infants
who inhale nasally and have irregular breathing patterns and small
airways. Aim: To compare the dose delivered to the lungs of HFA-BDP and
CFC-BDP at different breathing patterns using an upper airway model of an
infant. METHODS: An anatomically correct upper airway model of a
9-month-old child with an open nasal airway was connected to an impactor
and breathing simulator. HFA-BDP, 100 microg, and CFC-BDP, 100 micro g,
were delivered to the model through a detergent-coated, small-volume
spacer. The total dose leaving the model (lung dose), its particle size
distribution, and median mass aerodynamic diameter (MMAD) were assessed
during simulated tidal breathing with tidal volumes (VTs) of 50 mL, 100
mL, and 200 mL, and 30 breaths/min. Dose was expressed as percentage of
nominal dose. RESULTS: Lung doses for HFA-BDP were 25.4%, 26.5%, and 30.7%
compared with 6.8%, 4.8%, and 2.1% for CFC-BDP at VTs of 50 mL, 100 mL,
and 200 mL, respectively. The dose of particles < 2.1 microm to the lung
for HFA-BDP was 23 to 28% compared with 0.6 to 0.8% for CFC-BDP. The lung
dose of CFC-BDP mainly consisted of particles between 2.1 microm and 4.7
microm. MMAD for HFA-BDP was 1.2 microm, and 2.6 to 3.3 microm for CFC-BDP
depending on VT. The lung dose for CFC-BDP decreased significantly with
increasing VT. HFA-BDP lung dose did not alter significantly with VT.
CONCLUSIONS: In this infant model study, the use of HFA-BDP with a high
dose of particles < 2.1 microm improves the dose delivered to the lungs
substantially. Furthermore, the large proportion of extra-fine particles
in HFA-BDP results in lung doses less dependent on breathing pattern
compared with CFC-BDP
Diffusion weighted imaging in cystic fibrosis disease: beyond morphological imaging
To explore the feasibility of diffusion-weighted imaging (DWI) to assess inflammatory lung changes in patients with Cystic Fibrosis (CF) METHODS: CF patients referred for their annual check-up had spirometry, chest-CT and MRI on the same day. MRI was performed in a 1.5 T scanner with BLADE and EPI-DWI sequences (b = 0-600 s/mm(2)). End-inspiratory and end-expiratory scans were acquired in multi-row scanners. DWI was scored with an established semi-quantitative scoring system. DWI score was correlated to CT sub-scores for bronchiectasis (CF-CTBE), mucus (CF-CTmucus), total score (CF-CTtotal-score), FEV1, and BMI. T-test was used to assess differences between patients with and without DWI-hotspots
Crowdsourcing Airway Annotations in Chest Computed Tomography Images
Measuring airways in chest computed tomography (CT) scans is important for
characterizing diseases such as cystic fibrosis, yet very time-consuming to
perform manually. Machine learning algorithms offer an alternative, but need
large sets of annotated scans for good performance. We investigate whether
crowdsourcing can be used to gather airway annotations. We generate image
slices at known locations of airways in 24 subjects and request the crowd
workers to outline the airway lumen and airway wall. After combining multiple
crowd workers, we compare the measurements to those made by the experts in the
original scans. Similar to our preliminary study, a large portion of the
annotations were excluded, possibly due to workers misunderstanding the
instructions. After excluding such annotations, moderate to strong correlations
with the expert can be observed, although these correlations are slightly lower
than inter-expert correlations. Furthermore, the results across subjects in
this study are quite variable. Although the crowd has potential in annotating
airways, further development is needed for it to be robust enough for gathering
annotations in practice. For reproducibility, data and code are available
online: \url{http://github.com/adriapr/crowdairway.git}
Quantification of Lung Abnormalities in Cystic Fibrosis using Deep Networks
Cystic fibrosis is a genetic disease which may appear in early life with
structural abnormalities in lung tissues. We propose to detect these
abnormalities using a texture classification approach. Our method is a cascade
of two convolutional neural networks. The first network detects the presence of
abnormal tissues. The second network identifies the type of the structural
abnormalities: bronchiectasis, atelectasis or mucus plugging.We also propose a
network computing pixel-wise heatmaps of abnormality presence learning only
from the patch-wise annotations. Our database consists of CT scans of 194
subjects. We use 154 subjects to train our algorithms and the 40 remaining ones
as a test set. We compare our method with random forest and a single neural
network approach. The first network reaches an accuracy of 0,94 for disease
detection, 0,18 higher than the random forest classifier and 0,37 higher than
the single neural network. Our cascade approach yields a final class-averaged
F1-score of 0,33, outperforming the baseline method and the single network by
0,10 and 0,12.Comment: SPIE - Medical Imaging 2018: Image Processin
The development of bronchiectasis on chest computed tomography in children with cystic fibrosis: can pre-stages be identified?
Objective: Bronchiectasis is an important component of cystic fibrosis (CF) lung disease but little is known about its development. We aimed to study the development of bronchiectasis and identify determinants for rapid progression of bronchiectasis on chest CT. Methods: Forty-three patients with CF with at least four consecutive biennial volumetric CTs were included. Areas with bronchiectasis on the most recent CT were marked as regions of interest (ROIs). These ROIs were generated on all preceding CTs using deformable image registration. Observers indicated whether: bronchiectasis, mucus plugging, airway wall thickening, atelectasis/consolidation or normal airways were present in the ROIs. Results: We identified 362 ROIs on the most recent CT. In 187 (51.7 %) ROIs bronchiectasis was present on all preceding CTs, while 175 ROIs showed development of bronchiectasis. In 139/175 (79.4 %) no pre-stages of bronchiectasis were identified. In 36/175 (20.6 %) bronchiectatic airways the following pre-stages were identified: mucus plugging (17.7 %), airway wall thickening (1.7 %) or atelectasis/consolidation (1.1 %). Pancreatic insufficiency was more prevalent in the rapid progressors compared to the slow progressors (p = 0.05). Conclusion: Most bronchiectatic airways developed within 2 years without visible pre-stages, underlining the treacherous nature of CF lung disease. Mucus plugging was the most frequent pre-stage. Key Points: • Development of bronchiectasis in cystic fibrosis lung disease on CT.• Most bronchiectatic airways developed within 2 years without pre-stages.• The most frequently identified pre-stage was mucus plugging.• This study underlines the treacherous nature of CF lung disease
Variability of aerosol delivery via spacer devices in young asthmatic children in daily life
Pressurized metered dose inhalers (pMDI) are widely used together with
spacers for the treatment of asthma in children. However, the variability
of daily medication dose for pMDI/spacer combinations is not known.
Electrostatic charge is a potential source of dose variability. Metal
spacers have no static charge. This study assessed and compared
within-subject variability of aerosol delivery of metal and plastic
spacers. This was a randomized, crossover study in children with stable
asthma aged 1-4 (group I, n=17) and 5-8 (group II, n=16) yrs. In both
groups the amount of drug delivered to the mouth by a metal spacer
(Nebuchamber) and one of two plastic (polycarbonate) spacers, i.e.
Babyhaler in group I and Volumatic in group II was measured. The metal and
plastic spacers were tested at home in a randomized order for 7 days each,
using budesonide (200 microg b.i.d.). Aerosol was collected on a filter
positioned between spacer and facemask or mouth. Budesonide on the filter
was assessed by high performance liquid chromatography. The mean filter
dose for each child (mean+/-SD) during the 7 days was expressed as a
percentage of the nominal dose. Within-subject variability was expressed
as coefficient of variation (CV). Mean filter dose in group I was
41.7+/-10.1% for Nebuchamber and 26.0+/-4.0% for Babyhaler (p<0.001). Mean
filter dose in group II was 50.2+/-9.2% for Nebuchamber and 19.4+/-7.2%
for Volumatic (p<0.001). Mean CV in group I was 34% for Nebuchamber and
37% for Babyhaler (p=0.44). Mean CV in group II was 23% for Nebuchamber
and 34% for Volumatic (p=0.003). There was substantial within-subject dose
variability in aerosol delivery in children using a pMDI/spacer at home.
This variability was lower for the metal than for the plastic spacer in
children 5-8 yrs of age. The dose delivered to the mouth was about
two-fold higher fo
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