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Jim M Wild - One of the best experts on this subject based on the ideXlab platform.
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Airspace dimension assessment aida by inhaled nanoparticles benchmarking with hyperpolarised 129xe diffusion weighted lung mri
Scientific Reports, 2021Co-Authors: Madeleine Peterssonsjogren, Hofung Chan, Guilhem Collier, Graham Norquay, Lars E Olsson, Per Wollmer, Jakob Londahl, Jim M WildAbstract:Enlargements of distal Airspaces can indicate pathological changes in the lung, but accessible and precise techniques able to measure these regions are lacking. Airspace Dimension Assessment with inhaled nanoparticles (AiDA) is a new method developed for in vivo measurement of distal Airspace dimensions. The aim of this study was to benchmark the AiDA method against quantitative measurements of distal Airspaces from hyperpolarised 129Xe diffusion-weighted (DW)-lung magnetic resonance imaging (MRI). AiDA and 129Xe DW-MRI measurements were performed in 23 healthy volunteers who spanned an age range of 23–70 years. The relationship between the 129Xe DW-MRI and AiDA metrics was tested using Spearman’s rank correlation coefficient. Significant correlations were observed between AiDA distal Airspace radius (rAiDA) and mean 129Xe apparent diffusion coefficient (ADC) (p < 0.005), distributed diffusivity coefficient (DDC) (p < 0.001) and distal Airspace dimension (LmD) (p < 0.001). A mean bias of − 1.2 µm towards rAiDA was observed between 129Xe LmD and rAiDA, indicating that rAiDA is a measure of distal Airspace dimension. The AiDA R0 intercept correlated with MRI 129Xe α (p = 0.02), a marker of distal Airspace heterogeneity. This study demonstrates that AiDA has potential to characterize the distal Airspace microstructures and may serve as an alternative method for clinical examination of the lungs.
Fedja Netjasov - One of the best experts on this subject based on the ideXlab platform.
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framework for Airspace planning and design based on conflict risk assessment part 3 conflict risk assessment model for Airspace operational and current day planning
Transportation Research Part C-emerging Technologies, 2013Co-Authors: Fedja Netjasov, Obrad J BabicAbstract:Abstract This paper presents a natural continuation of author’s previous work that deals with the development of a conflict risk assessment model for the purpose of Airspace operational and current day planning under an Airspace planning and design framework based on conflict risk and task-load assessment. The model is intended to support an air traffic manager’s decision-making process during sectorization (for a given set of available sectors determined at tactical planning levels) through the evaluation of conflict risk and air traffic controller task-load. The model is based on the assumption that a conflict between a pair of aircraft exists when either horizontal or vertical separation minima are violated. Additionally, it was assumed that risk is a random variable. The developed model allows for estimation of the number of conflicts and the conflict probability, as well as their distribution at intersections and along an airway. It also allows for the determination of the air traffic controller’s task-load for a given Airspace and traffic load. The model is intended for use in en-route Airspace. An illustration of the model application shows that in addition to Airspace geometry, the total conflict risk also depends on aircraft speed, traffic demand and its spatial and temporal distribution in the Airspace as well as the applied separation minima. Finally, it was shown that the results of the model could be used by the air traffic managers in order to help them decide the necessary grouping (aggregation) or collapsing (disaggregation) of sectors (sectorization).
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framework for Airspace planning and design based on conflict risk assessment
Transportation Research Part C-emerging Technologies, 2012Co-Authors: Fedja NetjasovAbstract:This paper presents a framework for Airspace planning and design based on a conflict risk assessment developed for the purpose of preventing aircraft conflicts and collisions. The paper also presents a conflict risk assessment model developed for Airspace strategic planning, as a first step of the proposed framework. The model is intended to facilitate comparisons and sensitivity analyses of different Airspace designs and organizational scenarios under different traffic flow levels. Risk is assessed using two variables: the conflict probability and the number of conflicts in the observed Airspace under the given circumstances. The model is based on the concept of critical sections, which are traversed by the aircraft during level flight, or while climbing or descending through these sections. For a given pair of aircraft conflict probability is defined as product of the probability that one aircraft is in a critical section of its own trajectory, and the conditional probability that another aircraft is in its own critical section while the first aircraft is already in it. The number of conflicts is defined as the product of conflict probability and estimated traffic flows for the given airway. The final values for conflict numbers are determined taking into account all available flight levels and airway combinations in the given Airspace. The model provides an analysis of influence of separation reduction on conflict risk and could be used in both en-route and terminal manoeuvring Airspace.
Madeleine Peterssonsjogren - One of the best experts on this subject based on the ideXlab platform.
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Airspace dimension assessment aida by inhaled nanoparticles benchmarking with hyperpolarised 129xe diffusion weighted lung mri
Scientific Reports, 2021Co-Authors: Madeleine Peterssonsjogren, Hofung Chan, Guilhem Collier, Graham Norquay, Lars E Olsson, Per Wollmer, Jakob Londahl, Jim M WildAbstract:Enlargements of distal Airspaces can indicate pathological changes in the lung, but accessible and precise techniques able to measure these regions are lacking. Airspace Dimension Assessment with inhaled nanoparticles (AiDA) is a new method developed for in vivo measurement of distal Airspace dimensions. The aim of this study was to benchmark the AiDA method against quantitative measurements of distal Airspaces from hyperpolarised 129Xe diffusion-weighted (DW)-lung magnetic resonance imaging (MRI). AiDA and 129Xe DW-MRI measurements were performed in 23 healthy volunteers who spanned an age range of 23–70 years. The relationship between the 129Xe DW-MRI and AiDA metrics was tested using Spearman’s rank correlation coefficient. Significant correlations were observed between AiDA distal Airspace radius (rAiDA) and mean 129Xe apparent diffusion coefficient (ADC) (p < 0.005), distributed diffusivity coefficient (DDC) (p < 0.001) and distal Airspace dimension (LmD) (p < 0.001). A mean bias of − 1.2 µm towards rAiDA was observed between 129Xe LmD and rAiDA, indicating that rAiDA is a measure of distal Airspace dimension. The AiDA R0 intercept correlated with MRI 129Xe α (p = 0.02), a marker of distal Airspace heterogeneity. This study demonstrates that AiDA has potential to characterize the distal Airspace microstructures and may serve as an alternative method for clinical examination of the lungs.
Hironobu Nakamura - One of the best experts on this subject based on the ideXlab platform.
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lymphocytic interstitial pneumonia follow up ct findings in 14 patients
Journal of Thoracic Imaging, 2000Co-Authors: Takeshi Johkoh, Kazuya Ichikado, Masanori Akira, Osamu Honda, Noriyuki Tomiyama, Naoki Mihara, Seiki Hamada, T Kozuka, Mitsuhiro Koyama, Hironobu NakamuraAbstract:The aim of the present study was to assess the evolution of various computed tomographic (CT) findings of lymphocytic interstitial pneumonia (LIP) with determination of potentially reversible or irreversible features. The study included 14 patients with biopsy-proved LIP who had serial thin-section CT examination 4 to 82 months (median 13 months) apart. Initial and follow-up CT scans were evaluated independently and then directly compared with each other by two observers. The main parenchymal abnormalities on the initial CT scan consisted of ground-glass attenuation (n = 14), thickening of interlobular septa (n = 13), centrilobular nodules (n = 12), cystic Airspaces (n = 10), and Airspace consolidation (n = 4). On follow-up CT, nine patients improved, one showed no change, and four showed increased extent of disease. With the exception of cysts, the parenchymal opacities were reversible. On follow-up CT, new cysts were seen in three patients; these developed mainly in areas with centrilobular nodules on initial CT. Honeycombing was seen on follow-up CT in four patients; in three patients it developed in areas of Airspace consolidation and in one patient it developed in an area with ground-glass attenuation on initial CT. The majority of patients with LIP improved on follow-up. However, Airspace consolidation may progress to honeycombing and centrilobular nodules may precede cystic formation.
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lymphocytic interstitial pneumonia thin section ct findings in 22 patients
Radiology, 1999Co-Authors: Takeshi Johkoh, Kazuya Ichikado, Heather A Pickford, Thomas E Hartman, Masanori Akira, Osamu Honda, Nestor L. Müller, Hironobu NakamuraAbstract:PURPOSE: To assess the thin-section computed tomographic (CT) findings of lymphocytic interstitial pneumonia. MATERIALS AND METHODS: The study included 22 patients (five men, 17 women; age range, 24–83 years; mean age, 50 years) with biopsy-proved lymphocytic interstitial pneumonia. The CT scans were obtained by using 1–3-mm collimation and reconstructed by using a high-spatial-frequency algorithm. RESULTS: The predominant abnormalities consisted of areas of ground-glass attenuation and poorly defined centrilobular nodules present in all 22 patients and subpleural small nodules seen in 19 patients. Other common findings included thickening of bronchovascular bundles (n = 19), interlobular septal thickening (n = 18), cystic Airspaces (n = 15), and lymph node enlargement (n = 15). Less common findings included large nodules, emphysema, Airspace consolidation, bronchiectasis, architectural distortion, honeycombing, and pleural thickening. CONCLUSION: Lymphocytic interstitial pneumonia is characterized by the...
Hofung Chan - One of the best experts on this subject based on the ideXlab platform.
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Airspace dimension assessment aida by inhaled nanoparticles benchmarking with hyperpolarised 129xe diffusion weighted lung mri
Scientific Reports, 2021Co-Authors: Madeleine Peterssonsjogren, Hofung Chan, Guilhem Collier, Graham Norquay, Lars E Olsson, Per Wollmer, Jakob Londahl, Jim M WildAbstract:Enlargements of distal Airspaces can indicate pathological changes in the lung, but accessible and precise techniques able to measure these regions are lacking. Airspace Dimension Assessment with inhaled nanoparticles (AiDA) is a new method developed for in vivo measurement of distal Airspace dimensions. The aim of this study was to benchmark the AiDA method against quantitative measurements of distal Airspaces from hyperpolarised 129Xe diffusion-weighted (DW)-lung magnetic resonance imaging (MRI). AiDA and 129Xe DW-MRI measurements were performed in 23 healthy volunteers who spanned an age range of 23–70 years. The relationship between the 129Xe DW-MRI and AiDA metrics was tested using Spearman’s rank correlation coefficient. Significant correlations were observed between AiDA distal Airspace radius (rAiDA) and mean 129Xe apparent diffusion coefficient (ADC) (p < 0.005), distributed diffusivity coefficient (DDC) (p < 0.001) and distal Airspace dimension (LmD) (p < 0.001). A mean bias of − 1.2 µm towards rAiDA was observed between 129Xe LmD and rAiDA, indicating that rAiDA is a measure of distal Airspace dimension. The AiDA R0 intercept correlated with MRI 129Xe α (p = 0.02), a marker of distal Airspace heterogeneity. This study demonstrates that AiDA has potential to characterize the distal Airspace microstructures and may serve as an alternative method for clinical examination of the lungs.